Failsafe and RSSI questions

Okay, So I am slowly picking away and learning a ton here. Getting closer to a final setup.

My next hurdle are to calibrate my power module and figure out the RSSI data send.

I am running a tricopter with a HKpilot mega 2.7. Everything is linking with the computer and I have some arming issues still showing up but I think it is my location (Kitchen table) causing the trouble.


I am using a FrSky TFRSP for a RX. I have a failsafe setup where it goes into RTL when I shut off the transmitter but I cannot save a low throttle failsafe like before. I used several youtube tutorials and adjusted the endpoint to be 140% and set my failsafe on the RX. I then move the end point back up to 100% and calibrate the APM. Whenever I turn off the TX the APM goes into failsafe as it should even though the throttle stays the same.

It seems to be working, but not as it should.


The RX has PPM and RSSI outputs. Everything I read on the forum and wiki says that the APM can accept RSSI voltage ranges. Trouble is the RX documentation makes me believe the output is not a voltage but a PWM signal. Can I simply plug this into my APM to get RSSI signal information.

I run a FrSky X8R receiver which does provide a analog (0-3.3v) RSSI output and I do plug it into my APM 2.5 and it works well.

That being said, you can build or buy a simple RC (resistor - capacitor) filter that averages the digital pulses and provides a DC voltage. Easy enough to google to get the information.

Thanks, I did build one and it seems to be working great.

I think I am going to look into that it would take to get the video RSSI to display. That seems to be a useful feature.