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Every now and then it's good to pack light and leave the laptop at home and just enjoy flying. Running out of battery at inconvenient time is however a concern of mine. I just recently finished a project to display telemetry data from APM on Aurora's screen. I'm not particularly proud of the technical side of the implementation, but this seems to work fine.

Hitec's Optima receivers interface with "Sensor station" via I2C, receiver being the master. APM has I2C-bus and it should support multiple masters, but I could never get it working reliably. My solution was to use ATMega88 to receive data via SPI from APM and relay the data to forward by answering queries send by the receiver. The circuit itself is really simple, just the avr, two resistors and a decoupling capacitor.

All the information that could be get from the sensor station are emulated from the data from APM, even including fuel meter, which tells how much mAh are remaining from the rated capacity of the battery. Only thing that I haven't implemented is GPS position and time, since they are not really useful without a map. One nice thing is that on Aurora, you can rename temp and rpm labels. I'm using rpm-1 value for mAh's used and rpm-2 for airspeed. Temp-2 is used to show the current throttle (0-100). Temp-3 and 4 are still left for some other data.

I'm really happy to get this working, since all the important data is available from transmitter screen with one glance and since the APM sends the data via xbee, this is a nice to have backup feature.

If somebody wants to use this too, I can provide sources and schematic later.

br,

Janne