Bought a Jumper T12 Pro it’s smaller and lighter than my Jumper T16. The one thing that is really missing in my opinion is a momentary switch. I use it for 2 functions, the beeper on whoops that are equipped with one and to activate the ‘Roll over after crash’ function. The trim switches are not needed when flying whoops or any quad for that matter, the trim is done in the flight controller. So I got to digging around in OpenTX to see if it was possible to use the trim switches as momentary switches. As it turns out it’s fairly simple.
I found the easiest way to do this was using the OpenTX Companion but can be done using the radio too. Start in Flight modes and there you can disable the trims, I did it for all but will be using the Aileron trim for my momentary switch. Next stop is Mixers in my case I have Flip after crash on Channel 8. Here set the source to Aileron, set the weight to -500, set the offset to 500. Now go to source and set it to AileronTripLeft. This is all assuming that your using the Aileron trim for the momentary switch, if you us a different trim just adjust accordingly.