RC Remotes with smartpropoplus and rtl-sdr

Some years ago i loved smartpropoplus, a software that lets you use any rc remote with trainer port on you soundcard to emulate a windows gamecontroller.

Data test
Looks like PPM

While playing around with rtl-sdr i found out that my receiver can receive the 35mhz band and tried to capture some ppm data from a 35.11mhz Hitec Optic 6 remote and the results were great:

I decided to direct the fm decoded signal from sdrsharp via VB-Cable into smartpropoplus to check if it can be decoded and it worked.

smpp rtl1
Raspi as rtl-sdr receiver with sdrsharp and smartpropoplus

The next time i used a raspberry pi to receive the signal and direct it via rtl_fm and aplay into a soundcard input the same way the remote would be connected with a trainer cable.

The latency is pretty high because of rtl-sdr but this method works great with any remote control and it is not longer limited by a trainer port and you get some pretty good range.

It makes no difference in the delay if rtl_fm or sdrsharp is used but  rtl_fm is of course better for any „real“ use.