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Telemetry Release 0.1

Android App with SRF Stick

In the technical department at ARF (AKA BodTech), we've been wanting to get some live data (Telemetry) back from the car for a while. It would be way cool, and I'm sure we'll find some kind of use for it. So anyway, in the few weeks between the Rockingham and Anglesey race weekends I managed to find some time to work on it. The Batten 3 went out for the first time with a transceiver attached.

The transceiver on the Batten 3 was a Ciseco ARF, powered from a 3.3V 303 mA DC/DC converter, and attached via a MAX3232 TTL/RS232 serial converter. The other end was plugged into the trusty Raspberry Pi RaceComputer via the All Things Micro 4 port serial board.

On the other end was a Ciseco "SRF Stick" plugged into an Android mobile phone.

Most of the work in getting this running was in developing the Android application for the phone. The RaceComputer already recorded data from it's various sensors during the race, so adding a few additional functions to push some of that data out through a serial port was simple enough. For the initial release used at Anglesey we could request Telemetry Data (RPM, Advance, Speed, Location, Coolant Temp, Lambda, Gyro and Accelerometer information), or Lap Times (Last, Previous, and Best laps) in a request/response "One Shot" mode. The plan is to also have streaming mode, so the client just sends a start stream message and then waits for a continuous stream of updates. At Anglesey there was no ability to send messages to the car, but that is something we plan to have in place for Silverstone.

The Todo list currently looks like this:

  • Live Telemetry
  • Live Lap Timing
  • Pit-to-Driver Messaging
    • STOP!
    • Pit In
    • Speed Up
    • Slow Down
    • Free form message
  • Virtual Pit Board (Lap, Position, time deltas, etc)
  • Set start/finish line location
  • Live Car tracking on Google Maps

As of today, the outstanding items are the pit board, and setting the start/finish line location. Everything else is pretty much ready, we just need to put it through some testing. As well as getting live data, the app can load in a data log from a previous race and replay the telemetry and/or the google map tracking.

The only real problem we have is the range of the signal. At Anglesey we only managed to get around 50 meters, but the ARF is supposed to be able to reach upto 10km. We'd be happy with 2! I suspect the problem may be with the onboard antenna on the SRF Stick, but I'm going to seek some advice from the guys at Ciseco on that one.