F3F Wireless Timing System

UPDATE 31.10.2011
I posted following today in the BARCS Forum, reproduced here for those interested:

As mentioned above few posts, I developed a timing system since last winter. It is largely Arduino based since my intention was to open source it. I fumbled around quite long time with wireless base handles (Xbee Pro based) but finally preferred to abandon them for wires instead of stealing some pilot a good run time ;-(

My system is now ready for competition and is meant to be modular with some handy options and some room for refinements or adaptations.

Main CD device includes:
- large and very readable 20 x 4 LCD with contrast adjustment potentiometer
- SD card reader for pilot list and result logging
- wireless communication to the buzzer and to the large LED 7-segment display (could be replaced with wires)
- handy Wii Nunchuk joystick input
- 5000 mAh 7.4V lipo for "unlimited" power
- two buttons base grips
- secured plugs (D-Sub and XLR)

Sound module includes:
- wireless connection to main CD device (could be replaced with wires)
- Sound shield with SD card reader
- 3 languages support specific to language set for each pilot, for now English, German, and French (more to come)
- round number and pilot number spoken out
- all countdowns in voice
- lap counting too
- result time after lap
- reflight calls
- module includes a small amplifier connected to a horn loudspeaker
- module includes 2 12V relays to handle the 2-tone alarm buzzer

Display includes:
- large (10 cm high) 3 digit very bright LED 7-segment display
- wireless communication with main CD device and with wind station
- wind speed between runs
- countdown display
- run result display
- mounted on sturdy tripod up to 2m high

Wind station features:
- marine Windex wind vane equiped with tilt compensated digital compass
- calibrated hall sensor anemometer
- small LCD display with main information: instant wind speed, 20 second wind ok/ko
- wireless communication with main CD device and display module
- wind alarms transmission during run for reflights
- mean run windspeed and heading transmission at run end for logging

I am now in the process of listing the parts needed for each device. For now I only have a rough estimate for the cased CD device not including small internal wiring: about 290 CHF / 208 GBP with wireless comm, 245 CHF / 174 GBP without wireless comm. Could be somewhat cheaper when implementing chinese Arduino copy and other ebaying. I'll estimate the other modules in the coming days. Code will come for nothing and will be published, although lot of time was invested. Reward will come as improvement suggestions and a deeper sense of community ;-)

The part list budget for the wireless wind station including Davis Windex 15 wind vane, Inspeed Vortex anemometer kit, Arduino Uno board, 2 x 16 LCD, Xbee Pro RF-modem, and some 7.4V lipo is estimated to CHF 230 / 163 GBP. Replacing wireless with wires makes it less.

Two of main advantages of this system:
- voice was the most appreciated feature by pilots during the last F3F contests. Eyes are kept on the glider and everybody still knows what's going on.
- Arduino based: everybody can adapt/update the code for free through simplest USB link

There is some info (though partly outdated) and some pictures on my PureAirCarving blog for those interested. Questions welcomed, of course.

OLDER INFORMATION, PARTLY OUTDATED:
As I posted here and there once in a while, I thinkl I progressed quite a bit developing my Wireless F3F Timing System, though it is not fully ready yet for field testing.
I struggled quite a bit with the Wind Station Module. At first, I thought a digital compass module would be easy to implement for the wind direction, but I soon had to recognize the module I bought first wasn't doing the trick. It worked ok as long as the wind vane was turning in a perfectly horizontal plane. As soon as there was some banking, the heading values were off by some degrees. Since there is no light solution to have a wind vane perfectly stable on a mast in the field (hey, don't we like it when the wind shake those windstation masts?), I ordered another digital compass module, this time one that his fully tilt compensated by three accelerometers! Although slightly larger, this module is worling great and gives accurate heading readings even when banked. Well, with this one I could go on.
In the last couple days, I could spend some evening time programing the configuration processes on the CD Module. After some reflexion, this was in line with the thought that there could be some CDs that would like to do an F3F race with local rules differing from the FAI standards. For example, if some slope is really not flyable with less than 5 m/s wind speed, then my timing system could not be used! This would be a downfall, so I implemented a quite simple configuration process that the CD will go through efore each new round.
For now, the configuration steps are as follows:
1. FAI Rules (YES / no)
    if FAI Rules = no
    2. Set maximum wind deflection (default FAI and maximum is 45 degrees)
    3. Set minimum wind speed (default FAI is 3 m/s)
    4. Set maximum wind speed (default FAI is 25 m/s)
    5. Use launch countdown (default FAI 30 seconds / no)
    6. Use altitude gain countdown (default FAI 30 seconds / no)
    7. Use antidiving countdown (default FAI 5 seconds / no)
8. Use the Wireless LCD Display Module (YES / no)
9. Use the Wireless Sound Module (YES / no)
10. Use the Wireless Wind Station (YES / no)
11. Compute full race results (yes / NO)
I loaded some pictures of the first few screens on the CD Module display, just as teasers, to a gallery.
When I have some time once in a while, I'll update this page.
First case with CD device, joystick handle, wind device, anemometer, windvane and some 2-cells lipos