Hi all,
I found some other topics stating this problem and found various methods like hall effect sensor, counting the interrupts between the ESC and the motor and just use IR diodes. The last option is the easiest one, but the problem i have is that my propeller attached to the motor is attached to an aluminium pole of 30cm long wich is up, so it would be difficult to place the components in front and behind the propeller...
Does anyone know if counting the interrupts would be difficult? I have found a topic on DIY drones where they use the Eagletree rpm sensor, but it isn't all clear for me. (see: Brushless Motor RPM Sensor - Discussions - diydrones)
Anyone done projects where they measured the rpm of a brushless motor? My maximum would be 5000rpm.