I am creating a universal wireless controller with 2 joysticks, 4 pots, 2 momentary buttons, and 4 toggles. I am using an Arduino Mini Mega 2560 (ebay link) and the NRF24L01+PA+LNA. I am using 2x 18650 batteries in series for 7.4V total power from the battery. I then have a small perfboard where I have a 5V buck converter and a 3.3V buck converter. I am using the output from the 5V converter to power the arduino and for the pots and switches. I want to use the 3.3V output to power the NRF24 module.
The issue that I am having is that everything works fine and the unit transmits to another setup that I have with an Arduino when I have the 3V3 and GND pins connected to the 3.3V and GND pins of the arduino. However, when I change only these wires from the arduino's 3.3v supply to the 3.3v and GND coming from my buck converter, the device wont transmit anything. I've tested with a voltmeter and ahve 3.3V at the pins of the NRF24, but for some reason it wont work when connected to the buck converter power supply. I've even tried connecting the grounds of the 3.3v buck converter and the arduino and no such luck. However, if i switch it back to the NRF24 being powered from the arduino's 3.3v output, it starts transmitting again.
Any insights as to what I could be doing wrong are greatly appreciated.