Analog Inputs Reading incorrect values from Joysticks


Ive read all the threads realted to similar problems but I have a very big problem.

I was working with 2 arduino UNO to send joystick values from one NRF24L01 to another. Everything was working PERFECTLY..

Suddenly, I was changing the transmitter UNO's input joystick and started getting very unusual values on the serialprint of the analog inputs.

I thought my problem was on the joystick obviously, but when I tried to change it back to my original configuration it is not working.

My next step was to use the arduino UNO on the receptor as transmitter (by the way, by now I have already unplugged all the Tx and Rx electronics leaving the simplest circuit to read the joysticks (Pot)...

Now both arduinos keep the L pin (pin 13) in HIGH mode and the readings I am getting are very awkward.

I plug every AI to ground and get zeros, I plug every AI to 5V and get 1023, unplug them and get 200-300 values OK, THATS NORMAL.

But when I plug any joystick or potentiometer instead of just giving one and zeros, it seems as if the circuit pulls too much current off the board since an external LED I attached measures 5V but drops when connecting the potentiometer.

I dont post the connection schematic or the code because it is as simple as you can imagine and was working like a charm before I switched the UNO from one circuitry to another.

I need an expert to help me out because Ive been now (for a week) trying to get this working and cant. It seems like the simplest problem and yet I have not found any solutions.

Thank you very much in advance.... Help is urgent and would be appreciated.

Both are Arduino UNO R3 original bought from arduino webpage...


It appears to be working now by just changing the GND pin of the UNO from the GND next to the V5 PIN to the GND next to the Vin PIN.

Does anyone have an explanation for this? Can one GND pin be burned out and the other stiill working? By looking at the UNO schematics it doesnt seem likely.

I did NOT change any wires or electronics.

If you view the header at an angle then it’s easy to select the wrong socket. Remove all wires from the board and check for continuity between all ground pins.