1 == Using Altus Metrum Products
5 First off, in the US, you need an
6 link:http://www.altusmetrum.org/Radio/[amateur radio license]
7 or other authorization to legally operate the radio
8 transmitters that are part of our products.
13 In the rocket itself, you just need a flight computer
14 and a single-cell, 3.7 volt nominal Li-Po rechargeable
15 battery. An 850mAh battery weighs less than a 9V
16 alkaline battery, and will run a TeleMetrum, TeleMega
17 or EasyMega for hours. A 110mAh battery weighs less
18 than a triple A battery and is a good choice for use
19 with TeleMini or EasyMini.
21 By default, we ship TeleMini, TeleMetrum and TeleMega
22 flight computers with a simple wire antenna. If your
23 electronics bay or the air-frame it resides within is
24 made of carbon fiber, which is opaque to RF signals,
25 you may prefer to install an SMA connector so that you
26 can run a coaxial cable to an antenna mounted
27 elsewhere in the rocket. However, note that the GPS
28 antenna is fixed on all current products, so you
29 really want to install the flight computer in a bay
30 made of RF-transparent materials if at all possible.
34 To receive the data stream from the rocket, you need
35 an antenna and short feed-line connected to one of our
36 link:http://www.altusmetrum.org/TeleDongle/[TeleDongle]
37 units. If possible, use an SMA to BNC adapter instead
38 of feedline between the antenna feedpoint and
39 TeleDongle, as this will give you the best
40 performance. The TeleDongle in turn plugs directly
41 into the USB port on a notebook computer. Because
42 TeleDongle looks like a simple serial port, your
43 computer does not require special device
44 drivers... just plug it in.
46 The GUI tool, AltosUI, is written in Java and runs
47 across Linux, Mac OS and Windows. There's also a suite
48 of C tools for Linux which can perform most of the
51 Alternatively, a TeleBT attached with an SMA to BNC
52 adapter at the feed point of a hand-held yagi used in
53 conjunction with an Android device running AltosDroid
54 makes an outstanding ground station.
56 After the flight, you can use the radio link to
57 extract the more detailed data logged in either
58 TeleMetrum or TeleMini devices, or you can use a mini
59 USB cable to plug into the TeleMetrum board directly.
60 Pulling out the data without having to open up the
61 rocket is pretty cool! A USB cable is also how you
62 charge the Li-Po battery, so you'll want one of those
63 anyway... the same cable used by lots of digital
64 cameras and other modern electronic stuff will work
67 If your rocket lands out of sight, you may enjoy
68 having a hand-held GPS receiver, so that you can put
69 in a way-point for the last reported rocket position
70 before touch-down. This makes looking for your rocket
71 a lot like Geo-Caching... just go to the way-point and
72 look around starting from there. AltosDroid on an
73 Android device with GPS receiver works great for this,
76 You may also enjoy having a ham radio “HT” that covers
77 the 70cm band... you can use that with your antenna to
78 direction-find the rocket on the ground the same way
79 you can use a Walston or Beeline tracker. This can be
80 handy if the rocket is hiding in sage brush or a tree,
81 or if the last GPS position doesn't get you close
82 enough because the rocket dropped into a canyon, or
83 the wind is blowing it across a dry lake bed, or
84 something like that... Keith currently uses a Yaesu
85 FT1D, Bdale has a Yaesu VX-7R, which is a nicer radio
86 in most ways but doesn't support APRS.
88 So, to recap, on the ground the hardware you'll need includes:
90 . an antenna and feed-line or adapter
93 . optionally, a hand-held GPS receiver
94 . optionally, an HT or receiver covering 435 MHz
96 The best hand-held commercial directional antennas we've found for radio
97 direction finding rockets are from
98 link:http://www.arrowantennas.com/[Arrow Antennas].
100 The 440-3 and 440-5 are both good choices for finding
101 a TeleMetrum- or TeleMini- equipped rocket when used
102 with a suitable 70cm HT. TeleDongle and an SMA to BNC
103 adapter fit perfectly between the driven element and
104 reflector of Arrow antennas.
108 Our software makes it easy to log the data from each
109 flight, both the telemetry received during the flight
110 itself, and the more complete data log recorded in the
111 flash memory on the altimeter board. Once this data
112 is on your computer, our post-flight tools make it
113 easy to quickly get to the numbers everyone wants,
114 like apogee altitude, max acceleration, and max
115 velocity. You can also generate and view a standard
116 set of plots showing the altitude, acceleration, and
117 velocity of the rocket during flight. And you can
118 even export a TeleMetrum data file usable with Google
119 Maps and Google Earth for visualizing the flight path
120 in two or three dimensions!
122 Our ultimate goal is to emit a set of files for each
123 flight that can be published as a web page per flight,
124 or just viewed on your local disk with a web browser.
128 We have designed and prototyped several “companion
129 boards” that can attach to the companion connector on
130 TeleMetrum, TeleMega and EasyMega flight computers to
131 collect more data, provide more pyro channels, and so
132 forth. We do not yet know if or when any of these
133 boards will be produced in enough quantity to sell.
134 If you have specific interests for data collection or
135 control of events in your rockets beyond the
136 capabilities of our existing productions, please let
139 Because all of our work is open, both the hardware
140 designs and the software, if you have some great idea
141 for an addition to the current Altus Metrum family,
142 feel free to dive in and help! Or let us know what
143 you'd like to see that we aren't already working on,
144 and maybe we'll get excited about it too...
146 Watch our link:http://altusmetrum.org/[web site] for
147 more news and information as our family of products
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