Rotational speed of the fan attached to Ixora

Can I know the rotation speed of the fan attached to Ixora by the .NET application running on WinCE?

I want to detect that the fan has stopped due to a breakdown or the like.

Dear @kyas

The fan connector on the Ixora was designed as a simple electrical connection which can be turned on or off by software. I’m afraid there’s no circuit which would allow to measure the rotation speed.

Typical fans which support speed measuring are featuring an open-drain tachometer output. For such fans it should be possible to connect the tachometer output to one of the GPIO1-GPIO7 signals on Ixora’s X27 connector and add a pull-up resistor to 3.3V.
With this hardware setup you should be able to measure the pulses of the tachometer and calculate the speed.

However I never acturally tried this approach myself. Make sure that you don’t feed 12V into any GPIO pin, otherwise you will damage the Apalis module!

Regards, Andy

Dear andy.tx

Thank you very much for explaining in detail.
I will consider whether to measure fan rotation with GPIO PIN.