Posted by Steff Davies on January 4, 2009 at 7:34am
When I was a small boy, I used to watch the Jindivik target drones take off from Llanbedr (see http://www.airsceneuk.org.uk/hangar/1999/dera/targets.htm) on family holidays to North Wales, where my father was born. I've been interested in unmanned flight ever since.Currently, I have built nothing whatever in this line, but I have done a lot of reading (not least here - thanks Chris!). Ultimately, I'm thinking of a small electric fixed-wing based on a simple kit like the Multiplex Easy Star or Twinstar. My current thoughts on the rest of the kit:Mainboard: Gumstix OveroThe familiar Linux environment is too tempting to pass up, I think (I'm a Linux/BSD sysadmin by trade). Also, the surplus of CPU horsepower means that I can concentrate on getting something working in a scripting language and then making it faster rather than having speed as a constriction from the outset.Servo control: http://www.seetron.com/ssc.htmcheapish and lets me outsource the servo-control nastiness (of which I know very nearly nothing) in favour of talking to a serial port, which is more familiar territory.GPS: A 5Hz GPS module of some sort - there's a San Jose 32-channel on sparkfun which looks impressive. It appears to do serial output over two pins at 2.8V.IMU: I think this is going to have to be the Sparkfun 5DOF. I simply don't have the electronics chops to build my own, and anything nicer is going to cost too much for a first go-round.Telemetry: at least initially, wifi looks like the way to go. Unfortunately, the Overo currently lacks a wifi implementation, but there's a known-working USB dongle.This gives me a functional diagram like this:
Some Unresolved Questions (in no particular order):1) Serial connections. The Gumstix Summit board claims two "2-wire serial" connections - are these right for direct connection to the GPS module? To the servo controller board (I suspect not in this case)?2) Are the AD convertors on the Overo accurate enough (10bit) to be useful?3) Are they electrically compatible with the output from the IMU in any case?Have got the wrong end of any very important sticks? Have I made some glaring omission? I throw myself on your mercy.
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