The Altus Metrum System

1.1. Hooking Up Lithium Polymer Batteries
1.2. Hooking Up Pyro Charges
1.3. Hooking Up a Power Switch
1.4. Using a Separate Pyro Battery
1.5. Using a Different Kind of Battery

3.1. TeleMetrum Screw Terminals
3.2. Using a Separate Pyro Battery with TeleMetrum
3.3. Using an Active Switch with TeleMetrum

4.1. TeleMini v1.0 Screw Terminals
4.2. Using a Separate Pyro Battery with TeleMini v1.0
4.3. Using an Active Switch with TeleMini v1.0

5.1. TeleMini v2.0 Screw Terminals
5.2. Using a Separate Pyro Battery with TeleMini v2.0
5.3. Using an Active Switch with TeleMini v2.0

6.1. EasyMini Screw Terminals
6.2. Using a Separate Pyro Battery with EasyMini
6.3. Using an Active Switch with EasyMini

8. Flight Data Recording

7.1. TeleMega Screw Terminals
7.2. Using a Separate Pyro Battery with TeleMega
7.3. Using Only One Battery With TeleMega
7.4. Using an Active Switch with TeleMega

9. Installation

5. System Operation

1. Firmware Modes

2. GPS

3. Controlling An Altimeter Over The Radio Link

4. Ground Testing

5. Radio Link

6. APRS

7. Configurable Parameters

7.1. Radio Frequency
7.2. Callsign
7.3. Telemetry/RDF/APRS Enable
7.4. APRS Interval
7.5. Apogee Delay
7.6. Apogee Lockout
7.7. Main Deployment Altitude
7.8. Maximum Flight Log
7.9. Ignite Mode
7.10. Pad Orientation
7.11. Configurable Pyro Channels

6. AltosUI

1.1. Launch Pad
1.2. Ascent
1.3. Descent
1.4. Landed
1.5. Table
1.6. Site Map
1.7. Ignitor

4.1. Flight Graph
4.2. Configure Graph
4.3. Flight Statistics
4.4. Map

5.1. Comma Separated Value Format
5.2. Keyhole Markup Language (for Google Earth)

6.1. Main Deploy Altitude
6.2. Apogee Delay
6.3. Apogee Lockoug
6.4. Frequency
6.5. RF Calibration
6.6. Telemetry/RDF/APRS Enable
6.7. APRS Interval
6.8. Callsign
6.9. Maximum Flight Log Size
6.10. Ignitor Firing Mode
6.11. Pad Orientation
6.12. Beeper Frequency
6.13. Configure Pyro Channels

7.1. Voice Settings
7.2. Log Directory
7.3. Callsign
7.4. Imperial Units
7.5. Font Size
7.6. Serial Debug
7.7. Manage Frequencies

8.1. Frequency
8.2. Radio Calibration

7. AltosDroid

4.1. Pad

8. Using Altus Metrum Products

1. Being Legal
2. In the Rocket
3. On the Ground
4. Data Analysis
5. Future Plans

9. Altimeter Installation Recommendations

1. Mounting the Altimeter
2. Dealing with the Antenna
3. Preserving GPS Reception
4. Radio Frequency Interference
5. The Barometric Sensor
6. Ground Testing

10. Updating Device Firmware

1. - Updating TeleMega, TeleMetrum v2 or EasyMini Firmware -

1.1. Recovering From Self-Flashing Failure

11. Hardware Specifications

1. +

Table of Contents

1. Introduction and Overview

2. Getting Started

3. Handling Precautions

4. Altus Metrum Hardware

1.1. Hooking Up Lithium Polymer Batteries
1.2. Hooking Up Pyro Charges
1.3. Hooking Up a Power Switch
1.4. Using a Separate Pyro Battery
1.5. Using a Different Kind of Battery

3.1. TeleMetrum Screw Terminals
3.2. Using a Separate Pyro Battery with TeleMetrum
3.3. Using an Active Switch with TeleMetrum

4.1. TeleMini v1.0 Screw Terminals
4.2. Using a Separate Pyro Battery with TeleMini v1.0
4.3. Using an Active Switch with TeleMini v1.0

5.1. TeleMini v2.0 Screw Terminals
5.2. Using a Separate Pyro Battery with TeleMini v2.0
5.3. Using an Active Switch with TeleMini v2.0

6.1. EasyMini Screw Terminals
6.2. Using a Separate Pyro Battery with EasyMini
6.3. Using an Active Switch with EasyMini

9. Flight Data Recording

7.1. TeleMega Screw Terminals
7.2. Using a Separate Pyro Battery with TeleMega
7.3. Using Only One Battery With TeleMega
7.4. Using an Active Switch with TeleMega

8. EasyMega

8.1. EasyMega Screw Terminals
8.2. Using a Separate Pyro Battery with EasyMega
8.3. Using Only One Battery With EasyMega
8.4. Using an Active Switch with EasyMega

10. Installation

5. System Operation

1. Firmware Modes

2. GPS

3. Controlling An Altimeter Over The Radio Link

4. Ground Testing

5. Radio Link

6. APRS

7. Configurable Parameters

7.1. Radio Frequency
7.2. Callsign
7.3. Telemetry/RDF/APRS Enable
7.4. Telemetry baud rate
7.5. APRS Interval
7.6. APRS SSID
7.7. Apogee Delay
7.8. Apogee Lockout
7.9. Main Deployment Altitude
7.10. Maximum Flight Log
7.11. Ignite Mode
7.12. Pad Orientation
7.13. Configurable Pyro Channels

6. AltosUI

1.1. Launch Pad
1.2. Ascent
1.3. Descent
1.4. Landed
1.5. Table
1.6. Site Map
1.7. Ignitor

4.1. Flight Graph
4.2. Configure Graph
4.3. Flight Statistics
4.4. Map

5.1. Comma Separated Value Format
5.2. Keyhole Markup Language (for Google Earth)

6.1. Main Deploy Altitude
6.2. Apogee Delay
6.3. Apogee Lockoug
6.4. Frequency
6.5. RF Calibration
6.6. Telemetry/RDF/APRS Enable
6.7. Telemetry baud rate
6.8. APRS Interval
6.9. APRS SSID
6.10. Callsign
6.11. Maximum Flight Log Size
6.12. Ignitor Firing Mode
6.13. Pad Orientation
6.14. Beeper Frequency
6.15. Configure Pyro Channels

7.1. Voice Settings
7.2. Log Directory
7.3. Callsign
7.4. Imperial Units
7.5. Font Size
7.6. Serial Debug
7.7. Manage Frequencies

8.1. Frequency
8.2. RF Calibration
8.3. Telemetry Rate

7. AltosDroid

4.1. Pad

8. Using Altus Metrum Products

1. Being Legal
2. In the Rocket
3. On the Ground
4. Data Analysis
5. Future Plans

9. Altimeter Installation Recommendations

1. Mounting the Altimeter
2. Dealing with the Antenna
3. Preserving GPS Reception
4. Radio Frequency Interference
5. The Barometric Sensor
6. Ground Testing

10. Updating Device Firmware

1. + Updating TeleMega, TeleMetrum v2, EasyMega or EasyMini Firmware +

1.1. Recovering From Self-Flashing Failure

11. Hardware Specifications

1. TeleMega Specifications -
2. +
2. + EasyMega Specifications +
3. TeleMetrum v2 Specifications -
3. TeleMetrum v1 Specifications
4. +
4. TeleMetrum v1 Specifications
5. TeleMini v2.0 Specifications -
5. +
6. TeleMini v1.0 Specifications -
6. +
7. EasyMini Specifications -

12. FAQ

A. Notes for Older Software

B. Drill Templates

1. TeleMega template
2. TeleMetrum template
3. TeleMini v2/EasyMini template
4. TeleMini v1 template

C. Calibration

1. Radio Frequency
2. TeleMetrum and TeleMega Accelerometers

D. Release Notes

List of Tables

4.1. Altus Metrum Electronics
4.2. Altus Metrum Boards
4.3. TeleMetrum Screw Terminals
4.4. TeleMini v1.0 Connections
4.5. TeleMini v2.0 Connections
4.6. EasyMini Connections
4.7. TeleMega Screw Terminals
4.8. Data Storage on Altus Metrum altimeters
5.1. AltOS Modes
5.2. Pad/Idle Indications
5.3. Altus Metrum APRS Comments

Chapter 1. Introduction and Overview

12. FAQ

A. Notes for Older Software

B. Drill Templates

1. TeleMega template
2. EasyMega template
3. TeleMetrum template
4. TeleMini v2/EasyMini template
5. TeleMini v1 template

C. Calibration

1. Radio Frequency
2. TeleMetrum, TeleMega and EasyMega Accelerometers

D. Release Notes

List of Tables

4.1. Altus Metrum Electronics
4.2. Altus Metrum Boards
4.3. TeleMetrum Screw Terminals
4.4. TeleMini v1.0 Connections
4.5. TeleMini v2.0 Connections
4.6. EasyMini Connections
4.7. TeleMega Screw Terminals
4.8. EasyMega Screw Terminals
4.9. Data Storage on Altus Metrum altimeters
5.1. AltOS Modes
5.2. Pad/Idle Indications
5.3. Altus Metrum APRS Comments

Chapter 1. Introduction and Overview

Welcome to the Altus Metrum community! Our circuits and software reflect our passion for both hobby rocketry and Free Software. We hope their capabilities and performance will delight you in every way, but by @@ -103,6 +107,10 @@ NAR

EasyMini is a dual-deploy altimeter with logging and built-in USB data download. +

+ EasyMega is essentially a TeleMega board with the GPS receiver + and telemetry transmitter removed. It offers the same 6 pyro + channels and integrated gyroscopes for staging/air-start inhibit.

TeleDongle was our first ground station, providing a USB to RF interfaces for communicating with the altimeters. Combined with @@ -121,11 +129,11 @@ NAR More products will be added to the Altus Metrum family over time, and we currently envision that this will be a single, comprehensive manual for the entire product family. -

Chapter 2. Getting Started

The first thing to do after you check the inventory of parts in your “starter kit” is to charge the battery.

- For TeleMetrum and TeleMega, the battery can be charged by plugging it into the + For TeleMetrum, TeleMega and EasyMega, the battery can be charged by plugging it into the corresponding socket of the device and then using the USB cable to plug the flight computer into your computer's USB socket. The on-board circuitry will charge the battery whenever it is plugged @@ -144,7 +152,7 @@ NAR to trickle charge. It can take several hours to fully recharge a deeply discharged battery.

- TeleMetrum v2.0 and TeleMega use a higher power battery charger, + TeleMetrum v2.0, TeleMega and EasyMega use a higher power battery charger, allowing them to charge the battery while running the board at maximum power. When the battery is charging, or when the board is consuming a lot of power, the red LED will be lit. When the @@ -191,7 +199,7 @@ NAR over USB with your laptop computer; it acts exactly like a TeleDongle. Anywhere this manual talks about TeleDongle, you can also read that as 'and TeleBT when connected via USB'. -

Chapter 3. Handling Precautions

All Altus Metrum products are sophisticated electronic devices. When handled gently and properly installed in an air-frame, they will deliver impressive results. However, as with all electronic @@ -230,7 +238,7 @@ NAR As with all other rocketry electronics, Altus Metrum altimeters must be protected from exposure to corrosive motor exhaust and ejection charge gasses. -

Chapter 4. Altus Metrum Hardware

Table of Contents

1.1. Hooking Up Lithium Polymer Batteries
1.2. Hooking Up Pyro Charges
1.3. Hooking Up a Power Switch
1.4. Using a Separate Pyro Battery
1.5. Using a Different Kind of Battery

3.1. TeleMetrum Screw Terminals
3.2. Using a Separate Pyro Battery with TeleMetrum
3.3. Using an Active Switch with TeleMetrum

4.1. TeleMini v1.0 Screw Terminals
4.2. Using a Separate Pyro Battery with TeleMini v1.0
4.3. Using an Active Switch with TeleMini v1.0

5.1. TeleMini v2.0 Screw Terminals
5.2. Using a Separate Pyro Battery with TeleMini v2.0
5.3. Using an Active Switch with TeleMini v2.0

6.1. EasyMini Screw Terminals
6.2. Using a Separate Pyro Battery with EasyMini
6.3. Using an Active Switch with EasyMini

8. Flight Data Recording

7.1. TeleMega Screw Terminals
7.2. Using a Separate Pyro Battery with TeleMega
7.3. Using Only One Battery With TeleMega
7.4. Using an Active Switch with TeleMega

9. Installation

1. General Usage Instructions

Chapter 4. Altus Metrum Hardware

Table of Contents

1.1. Hooking Up Lithium Polymer Batteries
1.2. Hooking Up Pyro Charges
1.3. Hooking Up a Power Switch
1.4. Using a Separate Pyro Battery
1.5. Using a Different Kind of Battery

3.1. TeleMetrum Screw Terminals
3.2. Using a Separate Pyro Battery with TeleMetrum
3.3. Using an Active Switch with TeleMetrum

4.1. TeleMini v1.0 Screw Terminals
4.2. Using a Separate Pyro Battery with TeleMini v1.0
4.3. Using an Active Switch with TeleMini v1.0

5.1. TeleMini v2.0 Screw Terminals
5.2. Using a Separate Pyro Battery with TeleMini v2.0
5.3. Using an Active Switch with TeleMini v2.0

6.1. EasyMini Screw Terminals
6.2. Using a Separate Pyro Battery with EasyMini
6.3. Using an Active Switch with EasyMini

9. Flight Data Recording

7.1. TeleMega Screw Terminals
7.2. Using a Separate Pyro Battery with TeleMega
7.3. Using Only One Battery With TeleMega
7.4. Using an Active Switch with TeleMega

8. EasyMega

8.1. EasyMega Screw Terminals
8.2. Using a Separate Pyro Battery with EasyMega
8.3. Using Only One Battery With EasyMega
8.4. Using an Active Switch with EasyMega

10. Installation

1. General Usage Instructions

Here are general instructions for hooking up an Altus Metrum flight computer. Instructions specific to each model will be found in the section devoted to that model below. @@ -240,7 +248,7 @@ NAR twist pairs of wires connected to the board. Twist the switch leads, the pyro leads and the battery leads. This reduces interference through a mechanism called common mode rejection. -

1.1. Hooking Up Lithium Polymer Batteries

All Altus Metrum flight computers have a two pin JST PH series connector to connect up a single-cell Lithium Polymer cell (3.7V nominal). You can purchase matching batteries @@ -254,7 +262,7 @@ NAR this same connector. All that we have found use the opposite polarity, and if you use them that way, you will damage or destroy the flight computer. -

1.2. Hooking Up Pyro Charges

Altus Metrum flight computers always have two screws for each pyro charge. This means you shouldn't need to put two wires into a screw terminal or connect leads from pyro @@ -265,13 +273,13 @@ NAR The other lead is connected through the pyro circuit, which is connected to the negative battery terminal when the pyro circuit is fired. -

1.3. Hooking Up a Power Switch

Altus Metrum flight computers need an external power switch to turn them on. This disconnects both the computer and the pyro charges from the battery, preventing the charges from firing when in the Off position. The switch is in-line with the positive battery terminal. -

1.3.1. Using an External Active Switch Circuit

You can use an active switch circuit, such as the Featherweight Magnetic Switch, with any Altus Metrum flight computer. These require three connections, one to @@ -280,7 +288,7 @@ NAR hook these up for each flight computer below. The follow the instructions that come with your active switch to connect it up. -

1.4. Using a Separate Pyro Battery

As mentioned above in the section on hooking up pyro charges, one lead for each of the pyro charges is connected through the power switch directly to the positive battery @@ -297,18 +305,18 @@ NAR circuit between the negative pyro terminal and the ground terminal, firing the igniter. Specific instructions on how to hook this up will be found in each section below. -

1.5. Using a Different Kind of Battery

EasyMini and TeleMini v2 are designed to use either a lithium polymer battery or any other battery producing between 4 and 12 volts, such as a rectangular 9V - battery. TeleMega and TeleMetrum are not designed for this, + battery. TeleMega, EasyMega and TeleMetrum are not designed for this, and must only be powered by a lithium polymer battery. Find instructions on how to use other batteries in the EasyMini and TeleMini sections below. -

2. Specifications

Here's the full set of Altus Metrum products, both in production and retired. -

Table 4.1. Altus Metrum Electronics

Device	Barometer	Z-axis accelerometer	GPS	3D sensors	Storage	RF Output	Battery
TeleMetrum v1.0	MP3H6115 10km (33k')	MMA2202 50g	SkyTraq	-	1MB	10mW	3.7V
TeleMetrum v1.1	MP3H6115 10km (33k')	MMA2202 50g	SkyTraq	-	2MB	10mW	3.7V
TeleMetrum v1.2	MP3H6115 10km (33k')	ADXL78 70g	SkyTraq	-	2MB	10mW	3.7V
TeleMetrum v2.0	MS5607 30km (100k')	MMA6555 102g	uBlox Max-7Q	-	8MB	40mW	3.7V
TeleMini v1.0	MP3H6115 10km (33k')	-	-	-	5kB	10mW	3.7V
TeleMini v2.0	MS5607 30km (100k')	-	-	-	1MB	10mW	3.7-12V
EasyMini v1.0	MS5607 30km (100k')	-	-	-	1MB	-	3.7-12V
TeleMega v1.0	MS5607 30km (100k')	MMA6555 102g	uBlox Max-7Q	MPU6000 HMC5883	8MB	40mW	3.7V

Table 4.2. Altus Metrum Boards

Device

Connectors

Screw Terminals

Width

Length

Tube Size

TeleMetrum

Table 4.1. Altus Metrum Electronics

Device	Barometer	Z-axis accelerometer	GPS	3D sensors	Storage	RF Output	Battery
TeleMetrum v1.0	MP3H6115 10km (33k')	MMA2202 50g	SkyTraq	-	1MB	10mW	3.7V
TeleMetrum v1.1	MP3H6115 10km (33k')	MMA2202 50g	SkyTraq	-	2MB	10mW	3.7V
TeleMetrum v1.2	MP3H6115 10km (33k')	ADXL78 70g	SkyTraq	-	2MB	10mW	3.7V
TeleMetrum v2.0	MS5607 30km (100k')	MMA6555 102g	uBlox Max-7Q	-	8MB	40mW	3.7V
TeleMini v1.0	MP3H6115 10km (33k')	-	-	-	5kB	10mW	3.7V
TeleMini v2.0	MS5607 30km (100k')	-	-	-	1MB	10mW	3.7-12V
EasyMini v1.0	MS5607 30km (100k')	-	-	-	1MB	-	3.7-12V
TeleMega v1.0	MS5607 30km (100k')	MMA6555 102g	uBlox Max-7Q	MPU6000 HMC5883	8MB	40mW	3.7V
EasyMega v1.0	MS5607 30km (100k')	MMA6555 102g	-	MPU6000 HMC5883	8MB	-	3.7V

Table 4.2. Altus Metrum Boards

Device	Connectors	Screw Terminals	Width	Length	Tube Size
TeleMetrum	Antenna Debug Companion @@ -352,7 +360,18 @@ NAR Pyro A-D Switch Pyro battery -	1¼ inch (3.18cm)	3¼ inch (8.26cm)	38mm coupler

3. TeleMetrum

1¼ inch (3.18cm)

3¼ inch (8.26cm)

38mm coupler

EasyMega

+ Debug + Companion + USB + Battery +

+ Apogee pyro + Main pyro + Pyro A-D + Switch + Pyro battery +

1¼ inch (3.18cm)

2¼ inch (5.62cm)

38mm coupler

3. TeleMetrum

TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to fit inside coupler for 29mm air-frame tubing, but using it in a tube that small in diameter may require some creativity in mounting and wiring @@ -363,13 +382,13 @@ NAR the e-matches for apogee and main ejection charges depart from the fin can end of the board, meaning an ideal “simple” avionics bay for TeleMetrum should have at least 10 inches of interior length. -

3.1. TeleMetrum Screw Terminals

TeleMetrum has six screw terminals on the end of the board opposite the telemetry antenna. Two are for the power switch, and two each for the apogee and main igniter circuits. Using the picture above and starting from the top, the terminals are as follows: -

Table 4.3. TeleMetrum Screw Terminals

Terminal #	Terminal Name	Description
1	Switch Output	Switch connection to flight computer
2	Switch Input	Switch connection to positive battery terminal
3	Main +	Main pyro channel common connection to battery +
4	Main -	Main pyro channel connection to pyro circuit
5	Apogee +	Apogee pyro channel common connection to battery +
6	Apogee -	Apogee pyro channel connection to pyro circuit

3.2. Using a Separate Pyro Battery with TeleMetrum

Table 4.3. TeleMetrum Screw Terminals

Terminal #	Terminal Name	Description
1	Switch Output	Switch connection to flight computer
2	Switch Input	Switch connection to positive battery terminal
3	Main +	Main pyro channel common connection to battery +
4	Main -	Main pyro channel connection to pyro circuit
5	Apogee +	Apogee pyro channel common connection to battery +
6	Apogee -	Apogee pyro channel connection to pyro circuit

3.2. Using a Separate Pyro Battery with TeleMetrum

As described above, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to @@ -388,7 +407,7 @@ NAR The other lead from each pyro charge is then inserted into the appropriate per-pyro channel screw terminal (terminal 4 for the Main charge, terminal 6 for the Apogee charge). -

3.3. Using an Active Switch with TeleMetrum

As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. @@ -397,7 +416,7 @@ NAR 2, the positive flight computer input is on terminal 1. To hook a lead to ground, solder a piece of wire, 24 to 28 gauge stranded, to the GND hole just above terminal 1. -

4. TeleMini v1.0

TeleMini v1.0 is ½ inches by 1½ inches. It was designed to fit inside an 18mm air-frame tube, but using it in a tube that small in diameter may require some creativity in @@ -410,7 +429,7 @@ NAR apogee and main ejection charges depart from the other end of the board, meaning an ideal “simple” avionics bay for TeleMini should have at least 9 inches of interior length. -

4.1. TeleMini v1.0 Screw Terminals

TeleMini v1.0 has four screw terminals on the end of the board opposite the telemetry antenna. Two are for the apogee and two are for main igniter circuits. There are also wires @@ -418,7 +437,7 @@ NAR picture above and starting from the top for the terminals and from the left for the power switch wires, the connections are as follows: -

Table 4.4. TeleMini v1.0 Connections

Terminal #	Terminal Name	Description
1	Apogee -	Apogee pyro channel connection to pyro circuit
2	Apogee +	Apogee pyro channel common connection to battery +
3	Main -	Main pyro channel connection to pyro circuit
4	Main +	Main pyro channel common connection to battery +
Left	Switch Output	Switch connection to flight computer
Right	Switch Input	Switch connection to positive battery terminal

4.2. Using a Separate Pyro Battery with TeleMini v1.0

Table 4.4. TeleMini v1.0 Connections

Terminal #	Terminal Name	Description
1	Apogee -	Apogee pyro channel connection to pyro circuit
2	Apogee +	Apogee pyro channel common connection to battery +
3	Main -	Main pyro channel connection to pyro circuit
4	Main +	Main pyro channel common connection to battery +
Left	Switch Output	Switch connection to flight computer
Right	Switch Input	Switch connection to positive battery terminal

4.2. Using a Separate Pyro Battery with TeleMini v1.0

As described above, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to @@ -439,7 +458,7 @@ NAR The other lead from each pyro charge is then inserted into the appropriate per-pyro channel screw terminal (terminal 3 for the Main charge, terminal 1 for the Apogee charge). -

4.3. Using an Active Switch with TeleMini v1.0

As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. Again, @@ -450,21 +469,21 @@ NAR power switch wire, the positive flight computer input is on the left power switch wire. Hook a lead to either of the mounting holes for a ground connection. -

5. TeleMini v2.0

TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more on-board data logging memory, a built-in USB connector and screw terminals for the battery and power switch. The larger board fits in a 24mm coupler. There's also a battery connector for a LiPo battery if you want to use one of those. -

5.1. TeleMini v2.0 Screw Terminals

TeleMini v2.0 has two sets of four screw terminals on the end of the board opposite the telemetry antenna. Using the picture above, the top four have connections for the main pyro circuit and an external battery and the bottom four have connections for the apogee pyro circuit and the power switch. Counting from the left, the connections are as follows: -

Table 4.5. TeleMini v2.0 Connections

Terminal #	Terminal Name	Description
Top 1	Main -	Main pyro channel connection to pyro circuit
Top 2	Main +	Main pyro channel common connection to battery +
Top 3	Battery +	Positive external battery terminal
Top 4	Battery -	Negative external battery terminal
Bottom 1	Apogee -	Apogee pyro channel connection to pyro circuit
Bottom 2	Apogee +	Apogee pyro channel common connection to - battery +
Bottom 3	Switch Output	Switch connection to flight computer
Bottom 4	Switch Input	Switch connection to positive battery terminal

5.2. Using a Separate Pyro Battery with TeleMini v2.0

Table 4.5. TeleMini v2.0 Connections

Terminal #	Terminal Name	Description
Top 1	Main -	Main pyro channel connection to pyro circuit
Top 2	Main +	Main pyro channel common connection to battery +
Top 3	Battery +	Positive external battery terminal
Top 4	Battery -	Negative external battery terminal
Bottom 1	Apogee -	Apogee pyro channel connection to pyro circuit
Bottom 2	Apogee +	Apogee pyro channel common connection to + battery +
Bottom 3	Switch Output	Switch connection to flight computer
Bottom 4	Switch Input	Switch connection to positive battery terminal

5.2. Using a Separate Pyro Battery with TeleMini v2.0

As described above, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to @@ -483,7 +502,7 @@ NAR the appropriate per-pyro channel screw terminal (top terminal 1 for the Main charge, bottom terminal 1 for the Apogee charge). -

5.3. Using an Active Switch with TeleMini v2.0

As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. Use @@ -493,20 +512,20 @@ NAR The positive battery terminal is available on bottom terminal 4, the positive flight computer input is on the bottom terminal 3. -

6. EasyMini

EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's designed to fit in a 24mm coupler tube. The connectors and screw terminals match TeleMini v2.0, so you can easily swap between EasyMini and TeleMini. -

6.1. EasyMini Screw Terminals

EasyMini has two sets of four screw terminals on the end of the board opposite the telemetry antenna. Using the picture above, the top four have connections for the main pyro circuit and an external battery and the bottom four have connections for the apogee pyro circuit and the power switch. Counting from the left, the connections are as follows: -

Table 4.6. EasyMini Connections

Terminal #	Terminal Name	Description
Top 1	Main -	Main pyro channel connection to pyro circuit
Top 2	Main +	Main pyro channel common connection to battery +
Top 3	Battery +	Positive external battery terminal
Top 4	Battery -	Negative external battery terminal
Bottom 1	Apogee -	Apogee pyro channel connection to pyro circuit
Bottom 2	Apogee +	Apogee pyro channel common connection to - battery +
Bottom 3	Switch Output	Switch connection to flight computer
Bottom 4	Switch Input	Switch connection to positive battery terminal

6.2. Using a Separate Pyro Battery with EasyMini

Table 4.6. EasyMini Connections

Terminal #	Terminal Name	Description
Top 1	Main -	Main pyro channel connection to pyro circuit
Top 2	Main +	Main pyro channel common connection to battery +
Top 3	Battery +	Positive external battery terminal
Top 4	Battery -	Negative external battery terminal
Bottom 1	Apogee -	Apogee pyro channel connection to pyro circuit
Bottom 2	Apogee +	Apogee pyro channel common connection to + battery +
Bottom 3	Switch Output	Switch connection to flight computer
Bottom 4	Switch Input	Switch connection to positive battery terminal

6.2. Using a Separate Pyro Battery with EasyMini

As described above, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to @@ -525,7 +544,7 @@ NAR the appropriate per-pyro channel screw terminal (top terminal 1 for the Main charge, bottom terminal 1 for the Apogee charge). -

6.3. Using an Active Switch with EasyMini

As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. Use @@ -535,19 +554,19 @@ NAR The positive battery terminal is available on bottom terminal 4, the positive flight computer input is on the bottom terminal 3. -

7. TeleMega

TeleMega is a 1¼ inch by 3¼ inch circuit board. It was designed to easily fit in a 38mm coupler. Like TeleMetrum, TeleMega has an accelerometer and so it must be mounted so that the board is aligned with the flight axis. It can be mounted either antenna up or down. -

7.1. TeleMega Screw Terminals

TeleMega has two sets of nine screw terminals on the end of the board opposite the telemetry antenna. They are as follows: -

Table 4.7. TeleMega Screw Terminals

Terminal #

Terminal Name

Description

Top 1

Switch Input

Switch connection to positive battery terminal

Top 2

Switch Output

Switch connection to flight computer

Top 3

GND

Ground connection for use with external active switch

Top 4

Main -

Main pyro channel connection to pyro circuit

Top 5

Main +

Main pyro channel common connection to battery +

Top 6

Apogee -

Apogee pyro channel connection to pyro circuit

Top 7

Apogee +

Apogee pyro channel common connection to battery +

Top 8

D -

D pyro channel connection to pyro circuit

Top 9

D +

D pyro channel common connection to battery +

Bottom 1

GND

Ground connection for negative pyro battery terminal

Bottom 2

Pyro

Positive pyro battery terminal

Bottom 3

Lipo

Table 4.7. TeleMega Screw Terminals

Terminal #	Terminal Name	Description
Top 1	Switch Input	Switch connection to positive battery terminal
Top 2	Switch Output	Switch connection to flight computer
Top 3	GND	Ground connection for use with external active switch
Top 4	Main -	Main pyro channel connection to pyro circuit
Top 5	Main +	Main pyro channel common connection to battery +
Top 6	Apogee -	Apogee pyro channel connection to pyro circuit
Top 7	Apogee +	Apogee pyro channel common connection to battery +
Top 8	D -	D pyro channel connection to pyro circuit
Top 9	D +	D pyro channel common connection to battery +
Bottom 1	GND	Ground connection for negative pyro battery terminal
Bottom 2	Pyro	Positive pyro battery terminal
Bottom 3	Lipo	Power switch output. Use to connect main battery to pyro battery input -
Bottom 4	A -	A pyro channel connection to pyro circuit
Bottom 5	A +	A pyro channel common connection to battery +
Bottom 6	B -	B pyro channel connection to pyro circuit
Bottom 7	B +	B pyro channel common connection to battery +
Bottom 8	C -	C pyro channel connection to pyro circuit
Bottom 9	C +	C pyro channel common connection to battery +

7.2. Using a Separate Pyro Battery with TeleMega

Bottom 4

A -

A pyro channel connection to pyro circuit

Bottom 5

A +

A pyro channel common connection to battery +

Bottom 6

B -

B pyro channel connection to pyro circuit

Bottom 7

B +

B pyro channel common connection to battery +

Bottom 8

C -

C pyro channel connection to pyro circuit

Bottom 9

C +

C pyro channel common connection to battery +

7.2. Using a Separate Pyro Battery with TeleMega

TeleMega provides explicit support for an external pyro battery. All that is required is to remove the jumper between the lipo terminal (Bottom 3) and the pyro terminal @@ -555,7 +574,7 @@ NAR (Bottom 1) and the positive pyro battery to the pyro battery input (Bottom 2). You can then use the existing pyro screw terminals to hook up all of the pyro charges. -

7.3. Using Only One Battery With TeleMega

Because TeleMega has built-in support for a separate pyro battery, if you want to fly with just one battery running both the computer and firing the charges, you need to @@ -563,7 +582,7 @@ NAR circuit. TeleMega has two screw terminals for this—hook a wire from the Lipo terminal (Bottom 3) to the Pyro terminal (Bottom 2). -

7.4. Using an Active Switch with TeleMega

As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. @@ -571,14 +590,50 @@ NAR The positive battery terminal is available on Top terminal 1, the positive flight computer input is on Top terminal 2. Ground is on Top terminal 3. -

8. Flight Data Recording

8. EasyMega

+ EasyMega is a 1¼ inch by 2¼ inch circuit board. It was + designed to easily fit in a 38mm coupler. Like TeleMetrum, + EasyMega has an accelerometer and so it must be mounted so that + the board is aligned with the flight axis. It can be mounted + either antenna up or down. +

8.1. EasyMega Screw Terminals

+ EasyMega has two sets of nine screw terminals on the end of + the board opposite the telemetry antenna. They are as follows: +

Table 4.8. EasyMega Screw Terminals

Terminal #	Terminal Name	Description
Top 1	Switch Input	Switch connection to positive battery terminal
Top 2	Switch Output	Switch connection to flight computer
Top 3	GND	Ground connection for use with external active switch
Top 4	Main -	Main pyro channel connection to pyro circuit
Top 5	Main +	Main pyro channel common connection to battery +
Top 6	Apogee -	Apogee pyro channel connection to pyro circuit
Top 7	Apogee +	Apogee pyro channel common connection to battery +
Top 8	D -	D pyro channel connection to pyro circuit
Top 9	D +	D pyro channel common connection to battery +
Bottom 1	GND	Ground connection for negative pyro battery terminal
Bottom 2	Pyro	Positive pyro battery terminal
Bottom 3	Lipo	+ Power switch output. Use to connect main battery to + pyro battery input +
Bottom 4	A -	A pyro channel connection to pyro circuit
Bottom 5	A +	A pyro channel common connection to battery +
Bottom 6	B -	B pyro channel connection to pyro circuit
Bottom 7	B +	B pyro channel common connection to battery +
Bottom 8	C -	C pyro channel connection to pyro circuit
Bottom 9	C +	C pyro channel common connection to battery +

8.2. Using a Separate Pyro Battery with EasyMega

+ EasyMega provides explicit support for an external pyro + battery. All that is required is to remove the jumper + between the lipo terminal (Bottom 3) and the pyro terminal + (Bottom 2). Then hook the negative pyro battery terminal to ground + (Bottom 1) and the positive pyro battery to the pyro battery + input (Bottom 2). You can then use the existing pyro screw + terminals to hook up all of the pyro charges. +

8.3. Using Only One Battery With EasyMega

+ Because EasyMega has built-in support for a separate pyro + battery, if you want to fly with just one battery running + both the computer and firing the charges, you need to + connect the flight computer battery to the pyro + circuit. EasyMega has two screw terminals for this—hook a + wire from the Lipo terminal (Bottom 3) to the Pyro terminal + (Bottom 2). +

8.4. Using an Active Switch with EasyMega

+ As explained above, an external active switch requires three + connections, one to the positive battery terminal, one to + the flight computer positive input and one to ground. +

+ The positive battery terminal is available on Top terminal + 1, the positive flight computer input is on Top terminal + 2. Ground is on Top terminal 3. +

9. Flight Data Recording

Each flight computer logs data at 100 samples per second during ascent and 10 samples per second during descent, except for TeleMini v1.0, which records ascent at 10 samples per second and descent at 1 sample per second. Data are logged to an on-board flash memory part, which can be partitioned into several equal-sized blocks, one for each flight. -

Table 4.8. Data Storage on Altus Metrum altimeters

Device	Bytes per Sample	Total Storage	Minutes at Full Rate
TeleMetrum v1.0	8	1MB	20
TeleMetrum v1.1 v1.2	8	2MB	40
TeleMetrum v2.0	16	8MB	80
TeleMini v1.0	2	5kB	4
TeleMini v2.0	16	1MB	10
EasyMini	16	1MB	10
TeleMega	32	8MB	40

Table 4.9. Data Storage on Altus Metrum altimeters

Device	Bytes per Sample	Total Storage	Minutes at Full Rate
TeleMetrum v1.0	8	1MB	20
TeleMetrum v1.1 v1.2	8	2MB	40
TeleMetrum v2.0	16	8MB	80
TeleMini v1.0	2	5kB	4
TeleMini v2.0	16	1MB	10
EasyMini	16	1MB	10
TeleMega	32	8MB	40
EasyMega	32	8MB	40

The on-board flash is partitioned into separate flight logs, each of a fixed maximum size. Increase the maximum size of each log and you reduce the number of flights that can be @@ -587,7 +642,7 @@ NAR Configuration data is also stored in the flash memory on TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB of flash space. This configuration space is not available - for storing flight log data. TeleMetrum v2.0 and TeleMega + for storing flight log data. TeleMetrum v2.0, TeleMega and EasyMega store configuration data in a bit of eeprom available within the processor chip, leaving that space available in flash for more flight data. @@ -611,7 +666,7 @@ NAR from the flight computer before it fills up. The flight computer will still successfully control the flight even if it cannot log data, so the only thing you will lose is the data. -

9. Installation

10. Installation

A typical installation involves attaching only a suitable battery, a single pole switch for power on/off, and two pairs of wires connecting e-matches for the @@ -658,11 +713,11 @@ NAR and, on TeleMetrum v1, you can unplug the integrated GPS antenna and select an appropriate off-board GPS antenna with cable terminating in a U.FL connector. -

Chapter 5. System Operation

1. Firmware Modes

The AltOS firmware build for the altimeters has two fundamental modes, “idle” and “flight”. Which of these modes the firmware operates in is determined at start up time. For - TeleMetrum and TeleMega, which have accelerometers, the mode is + TeleMetrum, TeleMega and EasyMega, which have accelerometers, the mode is controlled by the orientation of the rocket (well, actually the board, of course...) at the time power is switched on. If the rocket is “nose up”, then @@ -689,7 +744,7 @@ NAR mode. In the description of the beeping pattern, “dit” means a short beep while "dah" means a long beep (three times as long). “Brap” means a long dissonant tone. -

Table 5.1. AltOS Modes

Mode Name

Abbreviation

Beeps

Description

Startup

battery voltage in decivolts

Table 5.1. AltOS Modes

Mode Name

Abbreviation

Beeps

Description

Startup

battery voltage in decivolts

Calibrating sensors, detecting orientation.

@@ -763,7 +818,7 @@ NAR slower than the “no continuity tone”)

Here's a summary of all of the “pad” and “idle” mode indications. -

Table 5.2. Pad/Idle Indications

Name

Beeps

Description

Neither

brap

Table 5.2. Pad/Idle Indications

Name

Beeps

Description

Neither

brap

No continuity detected on either apogee or main igniters. @@ -798,7 +853,8 @@ NAR beep. The flight computer will continue to report landed mode and beep out the maximum height until turned off.

- One “neat trick” of particular value when TeleMetrum or TeleMega are used with + One “neat trick” of particular value when TeleMetrum, TeleMega + or EasyMega are used with very large air-frames, is that you can power the board up while the rocket is horizontal, such that it comes up in idle mode. Then you can raise the air-frame to launch position, and issue a 'reset' command @@ -830,7 +886,7 @@ NAR together, then power TeleMini up. Once the red LED is lit, disconnect the wire and the board should signal that it's in 'idle' mode after the initial five second startup period. -

2. GPS

TeleMetrum and TeleMega include a complete GPS receiver. A complete explanation of how GPS works is beyond the scope of this manual, but the bottom line is that the GPS receiver @@ -848,7 +904,7 @@ NAR is turned back on, the GPS system should lock very quickly, typically long before igniter installation and return to the flight line are complete. -

3. Controlling An Altimeter Over The Radio Link

One of the unique features of the Altus Metrum system is the ability to create a two way command link between TeleDongle and an altimeter using the digital radio transceivers @@ -919,7 +975,7 @@ NAR lights on the devices. The red LED will flash each time a packet is transmitted, while the green LED will light up on TeleDongle when it is waiting to receive a packet from the altimeter. -

4. Ground Testing

An important aspect of preparing a rocket using electronic deployment for flight is ground testing the recovery system. Thanks to the bi-directional radio link central to the Altus Metrum system, @@ -935,7 +991,7 @@ NAR manual command. You can now command the altimeter to fire the apogee or main charges from a safe distance using your computer and TeleDongle and the Fire Igniter tab to complete ejection testing. -

5. Radio Link

Our flight computers all incorporate an RF transceiver, but it's not a full duplex system... each end can only be transmitting or receiving at any given moment. So we had to decide how to manage the @@ -968,7 +1024,7 @@ NAR 40mW devices. We hope to fly boards to higher altitudes over time, and would of course appreciate customer feedback on performance in higher altitude flights! -

6. APRS

TeleMetrum v2.0 and TeleMega can send APRS if desired, and the interval between APRS packets can be configured. As each APRS packet takes a full second to transmit, we recommend an @@ -986,17 +1042,25 @@ NAR have an older device that can receive the raw packets but isn't displaying position information, it's possible that this is the cause. +

+ APRS packets include an SSID (Secondary Station Identifier) + field that allows one operator to have multiple + transmitters. AltOS allows you to set this to a single digit + from 0 to 9, allowing you to fly multiple transmitters at the + same time while keeping the identify of each one separate in + the receiver. By default, the SSID is set to the last digit of + the device serial number.

The APRS packet format includes a comment field that can have arbitrary text in it. AltOS uses this to send status information about the flight computer. It sends four fields as shown in the following table. -

Table 5.3. Altus Metrum APRS Comments

Field	Example	Description
1	L	GPS Status U for unlocked, L for locked
2	6	Number of Satellites in View
3	B4.0	Altimeter Battery Voltage
4	A3.7	Apogee Igniter Voltage
5	M3.7	Main Igniter Voltage

Table 5.3. Altus Metrum APRS Comments

Field	Example	Description
1	L	GPS Status U for unlocked, L for locked
2	6	Number of Satellites in View
3	B4.0	Altimeter Battery Voltage
4	A3.7	Apogee Igniter Voltage
5	M3.7	Main Igniter Voltage
6	1286	Device Serial Number

Here's an example of an APRS comment showing GPS lock with 6 satellites in view, a primary battery at 4.0V, and - apogee and main igniters both at 3.7V. + apogee and main igniters both at 3.7V from device 1286.

-	  L6 B4.0 A3.7 M3.7
+	  L6 B4.0 A3.7 M3.7 1286

Make sure your primary battery is above 3.8V, any connected @@ -1011,7 +1075,7 @@ NAR that the GPS status character switches from 'L' to 'U'. Before GPS has locked, APRS will transmit zero for latitude, longitude and altitude. -

7. Configurable Parameters

Configuring an Altus Metrum altimeter for flight is very simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman filter means there is no need to set a @@ -1019,7 +1083,7 @@ NAR using AltosUI over USB or or radio link via TeleDongle. Read the Configure Altimeter section in the AltosUI chapter below for more information. -

7.1. Radio Frequency

Altus Metrum boards support radio frequencies in the 70cm band. By default, the configuration interface provides a list of 10 “standard” frequencies in 100kHz channels starting at @@ -1029,24 +1093,36 @@ NAR frequency will be used to avoid interference. And of course, both altimeter and TeleDongle must be configured to the same frequency to successfully communicate with each other. -

7.2. Callsign

This sets the callsign used for telemetry, APRS and the packet link. For telemetry and APRS, this is used to identify the device. For the packet link, the callsign must match that configured in AltosUI or the link will not work. This is to prevent accidental configuration of another Altus Metrum flight computer operating on the same frequency nearby. -

7.3. Telemetry/RDF/APRS Enable

You can completely disable the radio while in flight, if necessary. This doesn't disable the packet link in idle mode. -

7.4. APRS Interval

7.4. Telemetry baud rate

+ This sets the modulation bit rate for data transmission for + both telemetry and packet link mode. Lower bit + rates will increase range while reducing the amount of data + that can be sent and increasing battery consumption. All + telemetry is done using a rate 1/2 constraint 4 convolution + code, so the actual data transmission rate is 1/2 of the + modulation bit rate specified here. +

7.5. APRS Interval

This selects how often APRS packets are transmitted. Set this to zero to disable APRS without also disabling the regular telemetry and RDF transmissions. As APRS takes a full second to transmit a single position report, we recommend sending packets no more than once every 5 seconds. -

7.5. Apogee Delay

7.6. APRS SSID

+ This selects the SSID reported in APRS packets. By default, + it is set to the last digit of the serial number, but you + can change this to any value from 0 to 9. +

7.7. Apogee Delay

Apogee delay is the number of seconds after the altimeter detects flight apogee that the drogue charge should be fired. In most cases, this should be left at the default of 0. However, if you are flying @@ -1062,7 +1138,7 @@ NAR or 3 seconds later to avoid any chance of both charges firing simultaneously. We've flown several air-frames this way quite happily, including Keith's successful L3 cert. -

7.6. Apogee Lockout

7.8. Apogee Lockout

Apogee lockout is the number of seconds after boost where the flight computer will not fire the apogee charge, even if the rocket appears to be at apogee. This is often called @@ -1072,7 +1148,7 @@ NAR flight computers include a Kalman filter which is not fooled by this sharp pressure increase, and so this setting should be left at the default value of zero to disable it. -

7.7. Main Deployment Altitude

7.9. Main Deployment Altitude

By default, the altimeter will fire the main deployment charge at an elevation of 250 meters (about 820 feet) above ground. We think this is a good elevation for most air-frames, but feel free to change this @@ -1081,7 +1157,7 @@ NAR deployment elevation for the backup altimeter to be something lower than the primary so that both pyrotechnic charges don't fire simultaneously. -

7.8. Maximum Flight Log

7.10. Maximum Flight Log

Changing this value will set the maximum amount of flight log storage that an individual flight will use. The available storage is divided into as many flights of the @@ -1093,7 +1169,7 @@ NAR Even though our flight computers (except TeleMini v1.0) can store multiple flights, we strongly recommend downloading and saving flight data after each flight. -

7.9. Ignite Mode

7.11. Ignite Mode

Instead of firing one charge at apogee and another charge at a fixed height above the ground, you can configure the altimeter to fire both at apogee or both during @@ -1104,8 +1180,8 @@ NAR main allows some level of redundancy without needing two flight computers. In Redundant Apogee or Redundant Main mode, the two charges will be fired two seconds apart. -

7.10. Pad Orientation

- TeleMetrum and TeleMega measure acceleration along the axis +

7.12. Pad Orientation

+ TeleMetrum, TeleMega and EasyMega measure acceleration along the axis of the board. Which way the board is oriented affects the sign of the acceleration value. Instead of trying to guess which way the board is mounted in the air frame, the @@ -1114,9 +1190,9 @@ NAR of the board connected to the 70cm antenna to be nearest the nose of the rocket, with the end containing the screw terminals nearest the tail. -

7.11. Configurable Pyro Channels

7.13. Configurable Pyro Channels

In addition to the usual Apogee and Main pyro channels, - TeleMega has four additional channels that can be configured + TeleMega and EasyMega have four additional channels that can be configured to activate when various flight conditions are satisfied. You can select as many conditions as necessary; all of them must be met in order to activate the @@ -1141,7 +1217,7 @@ NAR height above the launch pad should be above or below that value.

- Orientation. TeleMega contains a 3-axis gyroscope and + Orientation. TeleMega and EasyMega contain a 3-axis gyroscope and accelerometer which is used to measure the current angle. Note that this angle is not the change in angle from the launch pad, but rather absolute relative to @@ -1214,7 +1290,7 @@ NAR Coast state (depending on how fast it is moving). If the computer detects upwards acceleration again, it will move back to Boost state. -

Chapter 6. AltosUI

Table of Contents

1.1. Launch Pad
1.2. Ascent
1.3. Descent
1.4. Landed
1.5. Table
1.6. Site Map
1.7. Ignitor

4.1. Flight Graph
4.2. Configure Graph
4.3. Flight Statistics
4.4. Map

5.1. Comma Separated Value Format
5.2. Keyhole Markup Language (for Google Earth)

6.1. Main Deploy Altitude
6.2. Apogee Delay
6.3. Apogee Lockoug
6.4. Frequency
6.5. RF Calibration
6.6. Telemetry/RDF/APRS Enable
6.7. APRS Interval
6.8. Callsign
6.9. Maximum Flight Log Size
6.10. Ignitor Firing Mode
6.11. Pad Orientation
6.12. Beeper Frequency
6.13. Configure Pyro Channels

7.1. Voice Settings
7.2. Log Directory
7.3. Callsign
7.4. Imperial Units
7.5. Font Size
7.6. Serial Debug
7.7. Manage Frequencies

8.1. Frequency
8.2. Radio Calibration

Chapter 6. AltosUI

Table of Contents

1.1. Launch Pad
1.2. Ascent
1.3. Descent
1.4. Landed
1.5. Table
1.6. Site Map
1.7. Ignitor

4.1. Flight Graph
4.2. Configure Graph
4.3. Flight Statistics
4.4. Map

5.1. Comma Separated Value Format
5.2. Keyhole Markup Language (for Google Earth)

6.1. Main Deploy Altitude
6.2. Apogee Delay
6.3. Apogee Lockoug
6.4. Frequency
6.5. RF Calibration
6.6. Telemetry/RDF/APRS Enable
6.7. Telemetry baud rate
6.8. APRS Interval
6.9. APRS SSID
6.10. Callsign
6.11. Maximum Flight Log Size
6.12. Ignitor Firing Mode
6.13. Pad Orientation
6.14. Beeper Frequency
6.15. Configure Pyro Channels

7.1. Voice Settings
7.2. Log Directory
7.3. Callsign
7.4. Imperial Units
7.5. Font Size
7.6. Serial Debug
7.7. Manage Frequencies

8.1. Frequency
8.2. RF Calibration
8.3. Telemetry Rate

The AltosUI program provides a graphical user interface for interacting with the Altus Metrum product family. AltosUI can monitor telemetry data, configure devices and many other @@ -1222,7 +1298,7 @@ NAR buttons, one for each major activity in the system. This chapter is split into sections, each of which documents one of the tasks provided from the top-level toolbar. -

1. Monitor Flight

Receive, Record and Display Telemetry Data

1. Monitor Flight

Receive, Record and Display Telemetry Data

Selecting this item brings up a dialog box listing all of the connected TeleDongle devices. When you choose one of these, AltosUI will create a window to display telemetry data as @@ -1269,7 +1345,7 @@ NAR data relevant to the current state of the flight. You can select other tabs at any time. The final 'table' tab displays all of the raw telemetry values in one place in a spreadsheet-like format. -

1.1. Launch Pad

The 'Launch Pad' tab shows information used to decide when the rocket is ready for flight. The first elements include red/green indicators, if any of these is red, you'll want to evaluate @@ -1319,7 +1395,7 @@ NAR The Launchpad tab also shows the computed launch pad position and altitude, averaging many reported positions to improve the accuracy of the fix. -

1.2. Ascent

This tab is shown during Boost, Fast and Coast phases. The information displayed here helps monitor the rocket as it heads towards apogee. @@ -1338,7 +1414,7 @@ NAR Finally, the current igniter voltages are reported as in the Launch Pad tab. This can help diagnose deployment failures caused by wiring which comes loose under high acceleration. -

1.3. Descent

Once the rocket has reached apogee and (we hope) activated the apogee charge, attention switches to tracking the rocket on the way back to the ground, and for dual-deploy flights, @@ -1367,7 +1443,7 @@ NAR e-matches are designed to retain continuity even after being fired, and will continue to show as green or return from red to green after firing. -

1.4. Landed

Once the rocket is on the ground, attention switches to recovery. While the radio signal is often lost once the rocket is on the ground, the last reported GPS position is @@ -1396,13 +1472,13 @@ NAR To get more detailed information about the flight, you can click on the 'Graph Flight' button which will bring up a graph window for the current flight. -

1.5. Table

The table view shows all of the data available from the flight computer. Probably the most useful data on this tab is the detailed GPS information, which includes horizontal dilution of precision information, and information about the signal being received from the satellites. -

1.6. Site Map

When the TeleMetrum has a GPS fix, the Site Map tab will map the rocket's position to make it easier for you to locate the rocket, both while it is in the air, and when it has landed. The @@ -1429,14 +1505,14 @@ NAR

You can pre-load images for your favorite launch sites before you leave home; check out the 'Preload Maps' section below. -

1.7. Ignitor

TeleMega includes four additional programmable pyro channels. The Ignitor tab shows whether each of them has continuity. If an ignitor has a low resistance, then the voltage measured here will be close to the pyro battery voltage. A value greater than 3.2V is required for a 'GO' status. -

2. Save Flight Data

The altimeter records flight data to its internal flash memory. TeleMetrum data is recorded at a much higher rate than the telemetry system can handle, and is not subject to radio drop-outs. As @@ -1465,7 +1541,7 @@ NAR The file name for each flight log is computed automatically from the recorded flight date, altimeter serial number and flight number information. -

3. Replay Flight

Select this button and you are prompted to select a flight record file, either a .telem file recording telemetry data or a .eeprom file containing flight data saved from the altimeter @@ -1474,7 +1550,7 @@ NAR Once a flight record is selected, the flight monitor interface is displayed and the flight is re-enacted in real time. Check the Monitor Flight chapter above to learn how this window operates. -

4. Graph Data

Select this button and you are prompted to select a flight record file, either a .telem file recording telemetry data or a .eeprom file containing flight data saved from @@ -1486,7 +1562,7 @@ NAR

Once a flight record is selected, a window with multiple tabs is opened. -

4.1. Flight Graph

By default, the graph contains acceleration (blue), velocity (green) and altitude (red).

@@ -1496,18 +1572,18 @@ NAR control and clicking and dragging allows the graph to be panned. The right mouse button causes a pop-up menu to be displayed, giving you the option save or print the plot. -

4.2. Configure Graph

This selects which graph elements to show, and, at the very bottom, lets you switch between metric and imperial units -

4.3. Flight Statistics

Shows overall data computed from the flight. -

4.4. Map

Shows a satellite image of the flight area overlaid with the path of the flight. The red concentric circles mark the launch pad, the black concentric circles mark the landing location. -

5. Export Data

This tool takes the raw data files and makes them available for external analysis. When you select this button, you are prompted to select a flight data file, which can be either a .eeprom or .telem. @@ -1516,7 +1592,7 @@ NAR Next, a second dialog appears which is used to select where to write the resulting file. It has a selector to choose between CSV and KML file formats. -

5.1. Comma Separated Value Format

This is a text file containing the data in a form suitable for import into a spreadsheet or other external data analysis tool. The first few lines of the file contain the version and @@ -1530,11 +1606,11 @@ NAR the sensor values are converted to standard units, with the barometric data reported in both pressure, altitude and height above pad units. -

5.2. Keyhole Markup Language (for Google Earth)

This is the format used by Google Earth to provide an overlay within that application. With this, you can use Google Earth to see the whole flight path in 3D. -

6. Configure Altimeter

Select this button and then select either an altimeter or TeleDongle Device from the list provided. Selecting a TeleDongle device will use the radio link to configure a remote altimeter. @@ -1562,14 +1638,14 @@ NAR lost.

The rest of the dialog contains the parameters to be configured. -

6.1. Main Deploy Altitude

This sets the altitude (above the recorded pad altitude) at which the 'main' igniter will fire. The drop-down menu shows some common values, but you can edit the text directly and choose whatever you like. If the apogee charge fires below this altitude, then the main charge will fire two seconds after the apogee charge fires. -

6.2. Apogee Delay

When flying redundant electronics, it's often important to ensure that multiple apogee charges don't fire at precisely the same time, as that can over pressurize the apogee deployment @@ -1577,7 +1653,7 @@ NAR Delay parameter tells the flight computer to fire the apogee charge a certain number of seconds after apogee has been detected. -

6.3. Apogee Lockoug

Apogee lockout is the number of seconds after boost where the flight computer will not fire the apogee charge, even if the rocket appears to be at apogee. This is often called @@ -1587,13 +1663,13 @@ NAR flight computers include a Kalman filter which is not fooled by this sharp pressure increase, and so this setting should be left at the default value of zero to disable it. -

6.4. Frequency

This configures which of the frequencies to use for both telemetry and packet command mode. Note that if you set this value via packet command mode, the TeleDongle frequency will also be automatically reconfigured to match so that communication will continue afterwards. -

6.5. RF Calibration

The radios in every Altus Metrum device are calibrated at the factory to ensure that they transmit and receive on the specified frequency. If you need to you can adjust the calibration @@ -1601,11 +1677,19 @@ NAR the value means, read the appendix on calibration and/or the source code for more information. To change a TeleDongle's calibration, you must reprogram the unit completely. -

6.6. Telemetry/RDF/APRS Enable

Enables the radio for transmission during flight. When disabled, the radio will not transmit anything during flight at all. -

6.7. APRS Interval

6.7. Telemetry baud rate

6.8. APRS Interval

How often to transmit GPS information via APRS (in seconds). When set to zero, APRS transmission is disabled. This option is available on TeleMetrum v2 and @@ -1613,15 +1697,19 @@ NAR packets. Note that a single APRS packet takes nearly a full second to transmit, so enabling this option will prevent sending any other telemetry during that time. -

6.8. Callsign

6.9. APRS SSID

+ Which SSID to report in APRS packets. By default, this is + set to the last digit of the serial number, but can be + configured to any value from 0 to 9. +

6.10. Callsign

This sets the call sign included in each telemetry packet. Set this as needed to conform to your local radio regulations. -

6.9. Maximum Flight Log Size

6.11. Maximum Flight Log Size

This sets the space (in kilobytes) allocated for each flight log. The available space will be divided into chunks of this size. A smaller value will allow more flights to be stored, a larger value will record data from longer flights. -

6.10. Ignitor Firing Mode

6.12. Ignitor Firing Mode

This configuration parameter allows the two standard ignitor channels (Apogee and Main) to be used in different configurations. @@ -1640,9 +1728,9 @@ NAR Altitude setting during descent. The 'apogee' channel is fired first, followed after a two second delay by the 'main' channel. -

6.11. Pad Orientation

- Because they include accelerometers, TeleMetrum and - TeleMega are sensitive to the orientation of the board. By +

6.13. Pad Orientation

+ Because they include accelerometers, TeleMetrum, + TeleMega and EasyMega are sensitive to the orientation of the board. By default, they expect the antenna end to point forward. This parameter allows that default to be changed, permitting the board to be mounted with the antenna pointing aft instead. @@ -1654,15 +1742,15 @@ NAR In this mode, the antenna end of the flight computer must point aft, in line with the expected flight path. -

6.12. Beeper Frequency

6.14. Beeper Frequency

The beeper on all Altus Metrum flight computers works best at 4000Hz, however if you have more than one flight computer in a single airframe, having all of them sound at the same frequency can be confusing. This parameter lets you adjust the base beeper frequency value. -

6.13. Configure Pyro Channels

6.15. Configure Pyro Channels

This opens a separate window to configure the additional - pyro channels available on TeleMega. One column is + pyro channels available on TeleMega and EasyMega. One column is presented for each channel. Each row represents a single parameter, if enabled the parameter must meet the specified test for the pyro channel to be fired. See the Pyro Channels @@ -1684,9 +1772,9 @@ NAR configuration along with the rest of the flight computer configuration by pressing the 'Save' button in the main Configure Flight Computer window. -

7. Configure AltosUI

This button presents a dialog so that you can configure the AltosUI global settings. -

7.1. Voice Settings

AltosUI provides voice announcements during flight so that you can keep your eyes on the sky and still get information about the current flight status. However, sometimes you don't want @@ -1695,7 +1783,7 @@ NAR Plays a short message allowing you to verify that the audio system is working and the volume settings are reasonable -

7.2. Log Directory

AltosUI logs all telemetry data and saves all TeleMetrum flash data to this directory. This directory is also used as the staring point when selecting data files for display or export. @@ -1703,7 +1791,7 @@ NAR Click on the directory name to bring up a directory choosing dialog, select a new directory and click 'Select Directory' to change where AltosUI reads and writes data files. -

7.3. Callsign

This value is transmitted in each command packet sent from TeleDongle and received from an altimeter. It is not used in telemetry mode, as the callsign configured in the altimeter board @@ -1716,40 +1804,40 @@ NAR the callsign configured here must exactly match the callsign configured in the flight computer. This matching is case sensitive. -

7.4. Imperial Units

This switches between metric units (meters) and imperial units (feet and miles). This affects the display of values use during flight monitoring, configuration, data graphing and all of the voice announcements. It does not change the units used when exporting to CSV files, those are always produced in metric units. -

7.5. Font Size

Selects the set of fonts used in the flight monitor window. Choose between the small, medium and large sets. -

7.6. Serial Debug

This causes all communication with a connected device to be dumped to the console from which AltosUI was started. If you've started it from an icon or menu entry, the output will simply be discarded. This mode can be useful to debug various serial communication issues. -

7.7. Manage Frequencies

This brings up a dialog where you can configure the set of frequencies shown in the various frequency menus. You can add as many as you like, or even reconfigure the default set. Changing this list does not affect the frequency settings of any devices, it only changes the set of frequencies shown in the menus. -

8. Configure Groundstation

- Select this button and then select a TeleDongle Device from the list provided. +

8. Configure Groundstation

+ Select this button and then select a TeleDongle or TeleBT Device from the list provided.

The first few lines of the dialog provide information about the connected device, including the product name, software version and hardware serial number. Below that are the individual configuration entries.

- Note that the TeleDongle itself doesn't save any configuration + Note that TeleDongle and TeleBT don't save any configuration data, the settings here are recorded on the local machine in - the Java preferences database. Moving the TeleDongle to + the Java preferences database. Moving the device to another machine, or using a different user account on the same machine will cause settings made here to have no effect.

@@ -1766,28 +1854,32 @@ NAR lost.

The rest of the dialog contains the parameters to be configured. -

8.1. Frequency

This configures the frequency to use for both telemetry and packet command mode. Set this before starting any operation involving packet command mode so that it will use the right frequency. Telemetry monitoring mode also provides a menu to change the frequency, and that menu also sets the same Java preference value used here. -

8.2. Radio Calibration

8.2. RF Calibration

The radios in every Altus Metrum device are calibrated at the factory to ensure that they transmit and receive on the - specified frequency. To change a TeleDongle's calibration, + specified frequency. To change a TeleDongle or TeleBT's calibration, you must reprogram the unit completely, so this entry simply shows the current value and doesn't allow any changes. -

9. Flash Image

8.3. Telemetry Rate

+ This lets you match the telemetry and packet link rate from + the transmitter. If they don't match, the device won't + receive any data. +

9. Flash Image

This reprograms Altus Metrum devices with new firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are all reprogrammed by using another similar unit as a - programming dongle (pair programming). TeleMega, TeleMetrum v2 + programming dongle (pair programming). TeleMega, EasyMega, TeleMetrum v2 and EasyMini are all programmed directly over their USB ports (self programming). Please read the directions for flashing devices in the Updating Device Firmware chapter below. -

10. Fire Igniter

This activates the igniter circuits in the flight computer to help test recovery systems deployment. Because this command can operate over the Packet Command Link, you can prepare the rocket as @@ -1807,14 +1899,14 @@ NAR you have 10 seconds to press the 'Fire' button or the system will deactivate, at which point you start over again at selecting the desired igniter. -

11. Scan Channels

This listens for telemetry packets on all of the configured frequencies, displaying information about each device it - receives a packet from. You can select which of the three - telemetry formats should be tried; by default, it only listens - for the standard telemetry packets used in v1.0 and later + receives a packet from. You can select which of the baud rates + and telemetry formats should be tried; by default, it only listens + at 38400 baud with the standard telemetry format used in v1.0 and later firmware. -

12. Load Maps

Before heading out to a new launch site, you can use this to load satellite images in case you don't have internet connectivity at the site. This loads a fairly large area @@ -1859,7 +1951,7 @@ NAR once, so if you load more than one launch site, you may get some gray areas in the map which indicate that Google is tired of sending data to you. Try again later. -

13. Monitor Idle

This brings up a dialog similar to the Monitor Flight UI, except it works with the altimeter in “idle” mode by sending query commands to discover the current state rather than @@ -1868,7 +1960,7 @@ NAR callsigns match exactly. If you can receive telemetry, but cannot manage to run Monitor Idle, then it's very likely that your callsigns are different in some way. -

Chapter 7. AltosDroid

Table of Contents

4.1. Pad

Chapter 7. AltosDroid

Table of Contents

4.1. Pad

1. - Updating TeleMega, TeleMetrum v2 or EasyMini Firmware -

AltosDroid provides the same flight monitoring capabilities as AltosUI, but runs on Android devices and is designed to connect to a TeleBT receiver over Bluetooth™. AltosDroid monitors @@ -1879,14 +1971,14 @@ NAR This manual will explain how to configure AltosDroid, connect to TeleBT, operate the flight monitoring interface and describe what the displayed data means. -

1. Installing AltosDroid

AltosDroid is available from the Google Play store. To install it on your Android device, open the Google Play Store application and search for “altosdroid”. Make sure you don't have a space between “altos” and “droid” or you probably won't find what you want. That should bring you to the right page from which you can download and install the application. -

2. Connecting to TeleBT

Press the Android 'Menu' button or soft-key to see the configuration options available. Select the 'Connect a device' option and then the 'Scan for devices' entry at the bottom to @@ -1896,19 +1988,19 @@ NAR Subsequent connections will not require you to enter that code, and your 'paired' device will appear in the list without scanning. -

3. Configuring AltosDroid

The only configuration option available for AltosDroid is which frequency to listen on. Press the Android 'Menu' button or soft-key and pick the 'Select radio frequency' entry. That brings up a menu of pre-set radio frequencies; pick the one which matches your altimeter. -

4. AltosDroid Flight Monitoring

AltosDroid is designed to mimic the AltosUI flight monitoring display, providing separate tabs for each stage of your rocket flight along with a tab containing a map of the local area with icons marking the current location of the altimeter and the Android device. -

4.1. Pad

The 'Launch Pad' tab shows information used to decide when the rocket is ready for flight. The first elements include red/green indicators, if any of these is red, you'll want to evaluate @@ -1956,26 +2048,26 @@ NAR The Launchpad tab also shows the computed launch pad position and altitude, averaging many reported positions to improve the accuracy of the fix. -

5. Downloading Flight Logs

AltosDroid always saves every bit of telemetry data it receives. To download that to a computer for use with AltosUI, simply remove the SD card from your Android device, or connect your device to your computer's USB port and browse the files on that device. You will find '.telem' files in the TeleMetrum directory that will work with AltosUI directly. -

Chapter 8. Using Altus Metrum Products

Table of Contents

1. Being Legal
2. In the Rocket
3. On the Ground
4. Data Analysis
5. Future Plans

1. Being Legal

Chapter 8. Using Altus Metrum Products

Table of Contents

1. Being Legal
2. In the Rocket
3. On the Ground
4. Data Analysis
5. Future Plans

1. Being Legal

First off, in the US, you need an amateur radio license or other authorization to legally operate the radio transmitters that are part of our products. -

2. In the Rocket

In the rocket itself, you just need a flight computer and a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An 850mAh battery weighs less than a 9V alkaline battery, and will - run a TeleMetrum or TeleMega for hours. + run a TeleMetrum, TeleMega or EasyMega for hours. A 110mAh battery weighs less than a triple A battery and is a good - choice for use with TeleMini. + choice for use with TeleMini or EasyMini.

- By default, we ship flight computers with a simple wire antenna. + By default, we ship TeleMini, TeleMetrum and TeleMega flight computers with a simple wire antenna. If your electronics bay or the air-frame it resides within is made of carbon fiber, which is opaque to RF signals, you may prefer to install an SMA connector so that you can run a coaxial cable to an @@ -1983,7 +2075,7 @@ NAR GPS antenna is fixed on all current products, so you really want to install the flight computer in a bay made of RF-transparent materials if at all possible. -

3. On the Ground

To receive the data stream from the rocket, you need an antenna and short feed-line connected to one of our TeleDongle units. If possible, use an SMA to BNC adapter instead of feedline between the antenna feedpoint and @@ -2020,8 +2112,8 @@ NAR if the rocket is hiding in sage brush or a tree, or if the last GPS position doesn't get you close enough because the rocket dropped into a canyon, or the wind is blowing it across a dry lake bed, or something like that... Keith - currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R - which isn't as nice, but was a whole lot cheaper. + currently uses a Yaesu FT1D, Bdale has a Yaesu VX-7R, which + is a nicer radio in most ways but doesn't support APRS.

So, to recap, on the ground the hardware you'll need includes:

@@ -2045,7 +2137,7 @@ NAR TeleMetrum- or TeleMini- equipped rocket when used with a suitable 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly between the driven element and reflector of Arrow antennas. -

4. Data Analysis

Our software makes it easy to log the data from each flight, both the telemetry received during the flight itself, and the more complete data log recorded in the flash memory on the altimeter @@ -2060,13 +2152,10 @@ NAR Our ultimate goal is to emit a set of files for each flight that can be published as a web page per flight, or just viewed on your local disk with a web browser. -

5. Future Plans

- We've designed a simple GPS based radio tracker called TeleGPS. - If all goes well, we hope to introduce this in the first - half of 2014. -

5. Future Plans

We have designed and prototyped several “companion boards” that - can attach to the companion connector on TeleMetrum and TeleMega + can attach to the companion connector on TeleMetrum, + TeleMega and EasyMega flight computers to collect more data, provide more pyro channels, and so forth. We do not yet know if or when any of these boards will be produced in enough quantity to sell. If you have specific @@ -2083,14 +2172,14 @@ NAR Watch our web site for more news and information as our family of products evolves! -

Chapter 9. Altimeter Installation Recommendations

Table of Contents

1. Mounting the Altimeter
2. Dealing with the Antenna
3. Preserving GPS Reception
4. Radio Frequency Interference
5. The Barometric Sensor
6. Ground Testing

Chapter 9. Altimeter Installation Recommendations

Table of Contents

1. Mounting the Altimeter
2. Dealing with the Antenna
3. Preserving GPS Reception
4. Radio Frequency Interference
5. The Barometric Sensor
6. Ground Testing

Building high-power rockets that fly safely is hard enough. Mix in some sophisticated electronics and a bunch of radio energy and some creativity and/or compromise may be required. This chapter contains some suggestions about how to install Altus Metrum products into a rocket air-frame, including how to safely and reliably mix a variety of electronics into the same air-frame. -

1. Mounting the Altimeter

The first consideration is to ensure that the altimeter is securely fastened to the air-frame. For most of our products, we prefer nylon standoffs and nylon screws; they're good to at least 50G @@ -2102,15 +2191,15 @@ NAR screw them through the TeleMini mounting holes, through the balsa and into the underlying material.

- Make sure accelerometer-equipped products like TeleMetrum and - TeleMega are aligned precisely along the axis of + Make sure accelerometer-equipped products like TeleMetrum, + TeleMega and EasyMega are aligned precisely along the axis of acceleration so that the accelerometer can accurately capture data during the flight.
Watch for any metal touching components on the board. Shorting out connections on the bottom of the board can cause the altimeter to fail during flight. -

2. Dealing with the Antenna

The antenna supplied is just a piece of solid, insulated, wire. If it gets damaged or broken, it can be easily replaced. It should be kept straight and not cut; bending or @@ -2153,7 +2242,7 @@ NAR SMA connector, and then run 50Ω coax from the board to the antenna. Building a remote antenna is beyond the scope of this manual. -

3. Preserving GPS Reception

The GPS antenna and receiver used in TeleMetrum and TeleMega is highly sensitive and normally have no trouble tracking enough satellites to provide accurate position information for @@ -2172,7 +2261,7 @@ NAR antenna as that's covered with a ground plane. But, keep wires and metal out from above the patch antenna.

4. Radio Frequency Interference

Any altimeter will generate RFI; the digital circuits use high-frequency clocks that spray radio interference across a wide band. Altus Metrum altimeters generate intentional radio @@ -2210,7 +2299,7 @@ NAR 70cm amateur band, so you should avoid lengths that are a simple ratio of that length; essentially any multiple of ¼ of the wavelength (17.5cm). -

5. The Barometric Sensor

Altusmetrum altimeters measure altitude with a barometric sensor, essentially measuring the amount of air above the rocket to figure out how high it is. A large number of @@ -2228,7 +2317,7 @@ NAR the products of APCP or BP combustion, so make sure the ebay is carefully sealed from any compartment which contains ejection charges or motors. -

6. Ground Testing

The most important aspect of any installation is careful ground testing. Bringing an air-frame up to the LCO table which hasn't been ground tested can lead to delays or ejection @@ -2250,10 +2339,10 @@ NAR interface through a TeleDongle to command each charge to fire. Make sure the charge is sufficient to robustly separate the air-frame and deploy the recovery system. -

Chapter 10. Updating Device Firmware

Table of Contents

1.1. Recovering From Self-Flashing Failure

1. + Updating TeleMega, TeleMetrum v2, EasyMega or EasyMini Firmware +

- TeleMega, TeleMetrum v2 and EasyMini are all programmed directly +

Chapter 10. Updating Device Firmware

Table of Contents

1.1. Recovering From Self-Flashing Failure