FAN BUS Controller

Wow the flow sensor is really easy :)
It has 3 pins (5Volt,Ground and signal), the Signal pin toggles from low to high twice per revolution of the tubine.

All I had to do on the Amtel is setup the external interrupt to trigger on a rising signal and in the ISR (interrupt service routine) increment a counter. In bascom avr thats 4 lines of code to setup the interupt and 3 to handle the interrupt itself.

Here's what the hardware looks like:-

All I need to do is calibrate it, when I know this I can display the actual flowrate in liters/min :)

Here's a picture of the test board:-

On to part 3 - flow sensor calibration