174 lines
6.3 KiB
HTML
174 lines
6.3 KiB
HTML
== Using Altus Metrum Products
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ifdef::radio[]
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=== Being Legal
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In the US, you need an
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link:http://www.altusmetrum.org/Radio/[amateur radio license]
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or other authorization to legally operate the radio
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transmitters that are part of our products.
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endif::radio[]
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=== In the Rocket
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In the rocket itself, you just need a flight computer
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and a single-cell, 3.7 volt nominal Li-Po rechargeable
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battery.
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ifdef::telemetrum,telemega,easymega,easytimer[]
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An 850mAh battery weighs less than a 9V
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alkaline battery, and will run a TeleMetrum, TeleMega,
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EasyMega or EasyTimer for hours.
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endif::telemetrum,telemega,easymega,easytimer[]
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A 110mAh battery weighs less
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than a triple A battery and is a good choice for use
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with
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ifdef::telemini[TeleMini or]
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EasyMini.
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ifdef::radio[]
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By default, we ship TeleMini, TeleMetrum and TeleMega
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flight computers with a simple wire antenna. If your
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electronics bay or the air-frame it resides within is
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made of carbon fiber, which is opaque to RF signals,
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you may prefer to install an SMA connector so that you
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can run a coaxial cable to an antenna mounted
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elsewhere in the rocket. However, note that the GPS
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antenna is fixed on all current products, so you
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really want to install the flight computer in a bay
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made of RF-transparent materials if at all possible.
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endif::radio[]
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=== On the Ground
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ifdef::radio[]
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To receive the data stream from the rocket, you need
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an antenna and short feed-line connected to one of our
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link:http://www.altusmetrum.org/TeleDongle/[TeleDongle]
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units. If possible, use an SMA to BNC adapter instead
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of feedline between the antenna feedpoint and
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TeleDongle, as this will give you the best
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performance. The TeleDongle in turn plugs directly
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into the USB port on a notebook computer. Because
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TeleDongle looks like a simple serial port, your
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computer does not require special device
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drivers... just plug it in.
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endif::radio[]
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The GUI tool, AltosUI, is written in Java and runs
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across Linux, Mac OS and Windows. There's also a suite
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of C tools for Linux which can perform most of the
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same tasks.
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ifdef::radio[]
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Alternatively, a TeleBT attached with an SMA to BNC
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adapter at the feed point of a hand-held yagi used in
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conjunction with an Android device running AltosDroid
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makes an outstanding ground station.
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endif::radio[]
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After the flight,
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ifdef::radio[]
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you can use the radio link to
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extract the more detailed data logged in either
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TeleMetrum or TeleMini devices, or
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endif::radio[]
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you can use a
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USB cable to plug into the flight computer board directly.
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A USB cable is also how you
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charge the Li-Po battery, so you'll want one of those
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anyway. The same cable used by lots of digital
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cameras and other modern electronic stuff will work
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fine.
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ifdef::gps[]
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If your rocket lands out of sight, you may enjoy
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having a hand-held GPS receiver, so that you can put
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in a way-point for the last reported rocket position
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before touch-down. This makes looking for your rocket
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a lot like Geo-Caching... just go to the way-point and
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look around starting from there. AltosDroid on an
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Android device with GPS receiver works great for this,
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too!
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endif::gps[]
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ifdef::radio[]
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You may also enjoy having a ham radio “HT” that covers
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the 70cm band... you can use that with your antenna to
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direction-find the rocket on the ground the same way
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you can use a Walston or Beeline tracker. This can be
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handy if the rocket is hiding in sage brush or a tree,
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or if the last GPS position doesn't get you close
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enough because the rocket dropped into a canyon, or
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the wind is blowing it across a dry lake bed, or
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something like that... Keith currently uses a Yaesu
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FT1D, Bdale has a Yaesu VX-7R, which is a nicer radio
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in most ways but doesn't support APRS.
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So, to recap, on the ground the hardware you'll need includes:
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. an antenna and feed-line or adapter
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. a TeleDongle
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. a notebook computer
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. optionally, a hand-held GPS receiver
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. optionally, an HT or receiver covering 435 MHz
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The best hand-held commercial directional antennas we've found for radio
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direction finding rockets are from
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link:http://www.arrowantennas.com/[Arrow Antennas].
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The 440-3 and 440-5 are both good choices for finding
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a TeleMetrum- or TeleMini- equipped rocket when used
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with a suitable 70cm HT. TeleDongle and an SMA to BNC
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adapter fit perfectly between the driven element and
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reflector of Arrow antennas.
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endif::radio[]
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=== Data Analysis
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Our software makes it easy to log the data from each
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flight, both the telemetry received during the flight
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itself, and the more complete data log recorded in the
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flash memory on the altimeter board. Once this data
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is on your computer, our post-flight tools make it
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easy to quickly get to the numbers everyone wants,
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like apogee altitude, max acceleration, and max
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velocity. You can also generate and view a standard
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set of plots showing the altitude, acceleration, and
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velocity of the rocket during flight. And you can
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even export a flight log in a format usable with Google
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Maps and Google Earth for visualizing the flight path
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in two or three dimensions!
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Our ultimate goal is to emit a set of files for each
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flight that can be published as a web page per flight,
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or just viewed on your local disk with a web browser.
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=== Future Plans
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ifdef::telemetrum,telemega,easymega[]
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We have designed and prototyped several “companion
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boards” that can attach to the companion connector on
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TeleMetrum, TeleMega and EasyMega flight computers to
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collect more data, provide more pyro channels, and so
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forth. We do not yet know if or when any of these
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boards will be produced in enough quantity to sell.
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If you have specific interests for data collection or
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control of events in your rockets beyond the
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capabilities of our existing productions, please let
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us know!
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endif::telemetrum,telemega,easymega[]
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Because all of our work is open, both the hardware
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designs and the software, if you have some great idea
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for an addition to the current Altus Metrum family,
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feel free to dive in and help! Or let us know what
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you'd like to see that we aren't already working on,
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and maybe we'll get excited about it too...
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Watch our link:http://altusmetrum.org/[web site] for
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more news and information as our family of products
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evolves!
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