The UAV development board
is back in stock at SparkFun.
SparkFun also plans to eventually carry 12" cables for the GPS connection, which could be used for the UAV development board, as well as for Chris Anderson's ArduPilot
. Sparkfun also plans to eventually carry 12" servo cables for connecting from the board to the RC receiver.
Presently, there is C code available for getting you started with the UAV development board. There are two separate programs. One is for simply making sure that the board is working, used at SparkFun to test the boards before they ship. This one is available both at SparkFun and on this website, and is the program that is in the board when it is shipped. There is also a program that I call "GentleNav", available on this website only. It is a port of the program that I have been using for a couple of years on my previous hardware platform. It performs pitch stabilization and/or RTL for an electric sailplane.
By the way, there is a "feature" of most GPS radios that you should be aware of if you plan to use both programs. If you command GPS radios to switch baud rate or between NMEA and binary formats, they only listen at the new baud rate and in the new format. If you run the "GentleNAV" program, it will switch to binary format with an NMEA command. If you then run the self test program, which trys to communicate in NMEA format, the GPS radio will ignore all commands, and the self test will indicate a failed GPS. If you plan to switch back and forth, you should revise the self test program to have it send the GPS command in binary format to switch to NMEA. With older GPS radios that I have used, they eventually default back to NMEA. The EM-406 somehow seems to forever remember the commands to switch, it will never switch back. I eventually plan to revise the self test program. In the meanwhile, it might be a good starting point for you to revise the self test program to send a binary command to the GPS to switch to NMEA format, its not hard to do.
You should also be aware that the status light on the EM-406 only works when the radio is in NMEA mode. At least I haven't figured out how to make it light in the binary mode, it just goes out. It resumes operation when you switch back to NMEA.
Presently, I am working on two projects related to the UAV development board. First, I am finishing up the documentation for the "GentleNav" firmware. Its taking longer than I thought. I will post a blog when it is done.
Second, I am working with Paul Bizard to develop theory and implementation for "artificial horizon" firmware for the UAV development board. It will combine gyro, accelerometer, and GPS information into a stable, responsive, accurate representation in matrix format of the orientation of the plane that it is mounted in. We believe we have a method that will work, but we have a few more details to work out. We will publish the theory when we have something we are satisfied with, and tested code some time later. What we have in mind is an algorithm that will maintain the 3X3 direction cosine matrix that describes the relative orientation of the plane and ground. Each entry in the matrix is the cosine of the angle between an axis on the plane and an axis on the ground.
Best regards to everyone, and acknowledgements to Chris Anderson, Paul Bizard, and all the staff at SparkFun for their help.