Hi all,
I am collaborating on a project that involves communicating two Arduinos via an nRF24L01 connection. The basic power setup is the following:
The RF24L01 is powered by its own 3.3v regulator. I added the jumper to the Arduino's Vin line because I will be debugging with the Arduino tethered to the PC to get status information through the serial monitor. I read somewhere that the Arduino does not like have a voltage at both the USB connector and the Vin line.
The problem is that when I connected the Arduino to the PC and applied the 7.2v to the 3.3.v regulator, the nRF24L01 started to get hot. The device (a robot) is already built, my responsibility is to get the software working. I was able to make the "engineering change" :-) to add the jumper. I am gong to reverse engineer the design to see if anything else pops out, but I wanted to ask here to see if there are any suggestions as to why the nRF24L01 is getting hot. A few additional remarks:
- I measured Vcc at the nRF24L01 and it is 3.3.volts, as expected.
- When the nRF24L01 got hot, the Vin jumper was already in place, so the Arduino was not getting any voltage from Vin.
- The highly recommended cap at the nRF24L01's Vcc/Gnd line is there.
- I rebuilt the basic nRF24L01 circuit from scratch and it works fine, but uses the 3.3v from the Arduino, not the independent regulator.
- I tested the nRF24L01 that got hot and it still works (sigh or relief)
Any suggestions or idea are welcomed. I can post the schematic when I have reversed engineered the design, but that won't happen till a week or so.
Best wishes, Salvador