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== Using Altus Metrum Products
ifdef::radio[]
=== Being Legal
In the US, you need an
link:http://www.altusmetrum.org/Radio/[amateur radio license]
or other authorization to legally operate the radio
transmitters that are part of our products.
endif::radio[]
=== 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.
ifdef::telemetrum,telemega,easymega[]
An 850mAh battery weighs less than a 9V
alkaline battery, and will run a TeleMetrum, TeleMega
or EasyMega for hours.
endif::telemetrum,telemega,easymega[]
A 110mAh battery weighs less
than a triple A battery and is a good choice for use
with
ifdef::telemini[TeleMini or]
EasyMini.
ifdef::radio[]
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 antenna mounted
elsewhere in the rocket. However, note that the 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.
endif::radio[]
=== On the Ground
ifdef::radio[]
To receive the data stream from the rocket, you need
an antenna and short feed-line connected to one of our
link:http://www.altusmetrum.org/TeleDongle/[TeleDongle]
units. If possible, use an SMA to BNC adapter instead
of feedline between the antenna feedpoint and
TeleDongle, as this will give you the best
performance. The TeleDongle in turn plugs directly
into the USB port on a notebook computer. Because
TeleDongle looks like a simple serial port, your
computer does not require special device
drivers... just plug it in.
endif::radio[]
The GUI tool, AltosUI, is written in Java and runs
across Linux, Mac OS and Windows. There's also a suite
of C tools for Linux which can perform most of the
same tasks.
ifdef::radio[]
Alternatively, a TeleBT attached with an SMA to BNC
adapter at the feed point of a hand-held yagi used in
conjunction with an Android device running AltosDroid
makes an outstanding ground station.
endif::radio[]
After the flight,
ifdef::radio[]
you can use the radio link to
extract the more detailed data logged in either
TeleMetrum or TeleMini devices, or
endif::radio[]
you can use a
USB cable to plug into the flight computer board directly.
A USB cable is also how you
charge the Li-Po battery, so you'll want one of those
anyway. The same cable used by lots of digital
cameras and other modern electronic stuff will work
fine.
ifdef::gps[]
If your rocket lands out of sight, you may enjoy
having a hand-held GPS receiver, so that you can put
in a way-point for the last reported rocket position
before touch-down. This makes looking for your rocket
a lot like Geo-Caching... just go to the way-point and
look around starting from there. AltosDroid on an
Android device with GPS receiver works great for this,
too!
endif::gps[]
ifdef::radio[]
You may also enjoy having a ham radio “HT” that covers
the 70cm band... you can use that with your antenna to
direction-find the rocket on the ground the same way
you can use a Walston or Beeline tracker. This can be
handy 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
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:
. an antenna and feed-line or adapter
. a TeleDongle
. a notebook computer
. optionally, a hand-held GPS receiver
. optionally, an HT or receiver covering 435 MHz
The best hand-held commercial directional antennas we've found for radio
direction finding rockets are from
link:http://www.arrowantennas.com/[Arrow Antennas].
The 440-3 and 440-5 are both good choices for finding
a 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.
endif::radio[]
=== 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 board. Once this data
is on your computer, our post-flight tools make it
easy to quickly get to the numbers everyone wants,
like apogee altitude, max acceleration, and max
velocity. You can also generate and view a standard
set of plots showing the altitude, acceleration, and
velocity of the rocket during flight. And you can
even export a flight log in a format usable with Google
Maps and Google Earth for visualizing the flight path
in two or three dimensions!
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.
=== Future Plans
ifdef::telemetrum,telemega,easymega[]
We have designed and prototyped several “companion
boards” that 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 interests for data collection or
control of events in your rockets beyond the
capabilities of our existing productions, please let
us know!
endif::telemetrum,telemega,easymega[]
Because all of our work is open, both the hardware
designs and the software, if you have some great idea
for an addition to the current Altus Metrum family,
feel free to dive in and help! Or let us know what
you'd like to see that we aren't already working on,
and maybe we'll get excited about it too...
Watch our link:http://altusmetrum.org/[web site] for
more news and information as our family of products
evolves!
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