This is my first attempt at a possible diagnostics app for the MR2, written using Google App Inventor. Unfortunately, I'm hitting a brick wall with this because the tablet is only running Android 1.6, which doesn't have a proper Bluetooth stack. App Inventor has Bluetooth coming out its ears, but can only target Android 2.o and above. I have tried playing with the Bluetooth backport to 1.6, but it won't work on this tablet. I've also scoured the 'Net to see if there is any way to run Android 2.0, but with only 128MByte of RAM this would be unlikely and very slow if I could find a build.
I'm holding out for a similar tablet at around £50 running Android 2.2 which should handle the Bluetooth with less trouble, if any.
Meanwhile the prototype diagnostics sender is coming along in dribs and drabs. I have an op-amp interface for the oxygen sensor and an RPM interface converting IG pulses to a linear voltage, not as elegant as counting the pulses, but a lot less hassle. The rest of the sensors kick out a signal in the 0-5v range so shouldn't need much pre-processing. The Bluetooth adaptor sends the data for 8 sensors out in formatted text (ASCII) once a second.