Rpm sensor not work because signal voltage less than 5v

I used futaba rpm sensor and connect to AUX 5 to measure the rpm, but no information to get.
I connect my aileron output directly to AUX 5, it works and get 7500 rpm
then I check the signal wire of rpm sensor, when the magnetic and hall sensor matched, voltage output from signal wire is only 4V(less then 5v), and after then magnetic go away, it output only 0.2v
So I guess is that the reason why I can’t get the rpm info. How can I solve it?

Hello jinchengde

How are you?

I am trying to integrate one RPM sensor and I think I am facing the same issue as you did.

My sensor provides 3.4 V in the signal line. Have you figure out if the voltage below 5V is a problem? How did you solve that?

Thanks in advance,

hi rmtorre,

which autopilot board you used? and what RPM sensor?
normally, connect the futaba rpm sensor to aux5 in pixhawk directly can work well
the problem I met is because the board is made by myself