Hello everyone ! Been facing a very weird problem. I am working on a project using a nano clone that displays text received with NRF24L01 module on a Sparkfun MicroOled (which is fully described here : Micro OLED Breakout Hookup Guide - SparkFun Learn).
I've managed to get the circuit working a couple weeks ago, but then i had to shorten the wires and resolder it. I changed the nano too. ALL OF A SUDDEN, the nano burns out, specifically the voltage regulator when i connected the circuit to pc (there is no problem with the pc voltage when i connect a raw nano). I already burnt 3 nanos. The Oled and Nrf24l01 work fine on an Uno R3 clone.
Both use SPI.
I provide you with a diagram of my circuit. Appreciate your help.
The 3.3V output of Nano has very limited current. Not enough to power NRF2401 I think. Unlike Uno, it does not have a dedicated 3.3V regulator, but provides a 3.3V output from the USB-serial chip, which can only supply a few tens of milliamps, if I remember correctly.
I don't know why it did not blow with your original circuit.
Thanks, i understand better now. Do you think using a RF24 nano would solve the problem ? Or is the integrated nrf24 consumes directly from 3v3 thus reducing the current output ?
One more question,
If i connect a 5V power supply to 5v pin and not Vin, is the current output from 5v gonna be the current of my power supply and not arduinos 5v pin current limit ?
Your question makes no sense to me. If you are using the 5V pin as power input, it's not going to output any current.
It is ok to power the Arduino this way, but you must use a multimeter to check that the power supply truly is 5V before you connect it to the Arduino.
If it is not 5V, connecting it to the Vin pin may not work correctly, but it is unlikely to burn the Arduino. But if it is more than 5.5V and you connect it to the Arduino's 5V pin, the Arduino will burn. That is what @jim-p is concerned about.
It worked before you did the resoldering and changing the Nano then ALL OF A SUDDEN after you did the resoldering and changed the Nano it burned out.
Do you think maybe you resoldered something wrong or the diferent Nano was bad.
Thats what i thought at first. Then... after burning 3 different nanos: elegoo, azdelivery (i soldered everything right, bc not only i had the diagram, but also quite precise photos of my previous circuit). I honestly think it is the matter of too much current being drawn from the 3v3 when arduino is connected to pc, because if i only connect the display it works fine (same for rf24). The mystery is why the previous current worked (and not just once, but for a week!)
The NRF can draw 25mA max and the display as far as I can figure only a couple of hundred microamps max
The max 3.3V output current is 50mA but I wouldn't go over maybe 40mA. So 25-26mA should not be a problem.
However, if you want to power the Nano through the 5V output, you have to be very very careful.
The power supply must be 5.0V, well regulated with low ripple and free of voltage spikes.
Do not connect anything to Vin or the USB port when powering via the 5V output pin.
Do NOT connect anything to Vin either accidentally or on purpose.
So i'll have to unplug the power source from 5v pin when the nano is connected to pc ? Even if the switch is in off position ?
P.s. the oled operates at 20mA max according to sparkfun. So the current eventually can go above 40mA in couple with the rf24
If the switch is off the boost is disconnected so it's OK to have USB connected
the oled operates at 20mA max according to sparkfun
I don't know how I missed that.
Also the display is 3.3V logic and you are driving it with 5V logic. That is a problem, you should be using a level shifter
