Teensy 4.1 in a drone not working

[Kinsey]

So, i'm currently working on my final project (High school). For which i'm building a drone, that is able to detect and avoid obstacles using a teensy 4.1 as a inbetween chip between the rc receiver and the flight controller on my drone. The drone opperates on ppm signals (which i'm able to read out, manipulate and send out again). The problem comes, when i don't connect the teensy 4.1 to ANY power (so no gnd and vcc) it still works fine, it seams that the two pins i use, pin 2 for read out and 17 for sending out the ppm signal are feeding the teensy with power (idk how that works). But when i now connect the teensy to the same powersupply my flightcontroller and receiver are both connected to it all off a sudden stops working, so the signals don't get send through no longer. I've checked my code, the powersupply, tryed resistors but nothing seams to work.
So if you have any ideas how i can fix this, feel free to tell me

And like some general infos about my stuff:
- microcontroller: Teensy 4.1
- rc receiver: Jeti duplex rx3
- flightcontroller: Omnibus f4
- cabling is alright i've checked it thousends of times already

all are connected to my battery on the drone
I have attached my code if it helps:

 

[BriComp]

A wiring diagram and/or a photo of the setup might help.

 

[Kinsey]

A wiring diagram and/or a photo of the setup might help.

yeah makes sense, give me two seconds,
so i didn't exactly found the flight controller i'm using, just know that the out form the receiver gets to pin 2 on the teensy and then pin 17 is connected to the rc input on the flightcontroller (here pin 44, aka rc). The flightcontroller and teensy should be conencted to the powersupply (battery)<w

 

[BriComp]

I find it difficult to understand what is happening from your description, but ONE alarming thing is that you have the output from the Receiver (which is powered by 5V) going to pin 2 on the Teensy. I don't know what output voltage the Receiver is giving BUT be aware that the Teensy is NOT 5V tolerant.
If you have put 5V on any of it's pins (besides Vin pin) it is likely that you have at the least destroyed that pin if not the complete Teensy.

To see if the Teensy has survived, try programming it with the LED blink program.

 

[Kinsey]

I find it difficult to understand what is happening from your description, but ONE alarming thing is that you have the output from the Receiver (which is powered by 5V) going to pin 2 on the Teensy. I don't know what output voltage the Receiver is giving BUT be aware that the Teensy is NOT 5V tolerant.
If you have put 5V on any of it's pins (besides Vin pin) it is likely that you have at the least destroyed that pin if not the complete Teensy.

To see if the Teensy has survived, try programming it with the LED blink program.

ah sry i forgot to mention (on the image i just put it together shortly) but normaly there would be a 2k Resistor inbetween, the teensy is completly fine i checked it (sry for the missunderstanding).
So let me try again:
The teensy runs even though its not connected to any powersource (so its only connected to the receiver data signal and the input for the rc signal on the flight controller).But as soon as i connect power to the teensy it stops working, idk if that made it clearer

 

[BriComp]

How do you know that the Teensy is working in this condition "The teensy runs even though its not connected to any powersource (so its only connected to the receiver data signal and the input for the rc signal on the flight controller)".

If it's because the rest of your circuit is working, it does NOT mean that the Teensy is.

Put some led blink code in your LOOP and see if the led flashes. If it does the Teensy is working, if it does not than the Teensy isn't.

 

[Kinsey]

How do you know that the Teensy is working in this condition "The teensy runs even though its not connected to any powersource (so its only connected to the receiver data signal and the input for the rc signal on the flight controller)".

If it's because the rest of your circuit is working, it does NOT mean that the Teensy is.

Put some led blink code in your LOOP and see if the led flashes. If it does the Teensy is working, if it does not than the Teensy isn't.

I'm asuming it does bc otherwise the signals wouldn't be processed and directed to the flightcontroller right?
But i'll try the blinking sketch

So 've tried it, and indeed the led doesn't blink, but then i really don't understand how and why the signal gets processed yk

 

[Kinsey]

yo,uhm so i tried it again with another microcontroller (arduino uno r4 wifi) and i still get the same "bug" (idk what it is)