The Arduino folks are really smart, and have some really good tools. Everything is automatic or almost. You change the code, and correct syntax is highlighted, incorrect is not. The uploader can be run using Control U, a pulldown menu, or from the shortcut button. I had to set my port and board:
- Port: COM4
- Board: ArduinoMega 1280
I need to at least come up with the block diagram of what hooks to what. Again, for analog inputs, I will have 4 J thermocouples, and 4 K thermocouples for the EGT and CHT's, oil pressure and temperature, fuel pressure and outside air temperature. For digital inputs, the RPM will need to be measured, probably on an interrupt. There is room for additional digital inputs, including landing gear position, flaps or spoiler position. Analog inputs for throttle, mixture and carb heat position. Outputs may include a speaker or input to the intercom, assorted LEDs, and finally using bluetooth, to the Android.
A consideration I have, the amplifiers needed for the thermocouples are somewhat expensive, like about $5 per chip. One chip per channel, meaning over $40 for amplifiers alone (or $60 if I used a 6 cylinder). That is more than I paid for the Arduino board. That is fine, but there is another way, using multiplexers. Something like a 4066 or another analog switch. I need to do that research.
I think the next thing I will do is start building the tester. It'll have a couple amplifiers for the thermocouples, then I'll have the connector for the other analog inputs, with some op-amp (lm324?) to allow scaling the inputs. Another digital input will be for the tachometer input (opto coupler?).