Hi all. I had thought that the Nano Every could accept up to 21V to the Vin and, in the case where USB was connected and Vin connected to an external power supply, it would automatically select the higher voltage source of the two. Is this not correct? I have now destroyed three boards by having the USB connected and 9V to Vin simultaneously. Everything works fine when the board is connected to just the USB, or just the 9V, but in a few cases when I've had them both connected simultaneously the board instantly fries. The ATMega chip quickly became extremely hot (hot enough to burn me when I touched it), and thereafter the board is dead. Is this a common issue with the Nano Every or is there something I may be doing wrong? Any thoughts would be appreciated, thanks.
Hi,
perhaps there is another problem...I connected many times USB and 12V to Vin without any problems. There should be a shotkey diode on USB that no voltage can be put on the USB port. So from board side it should be fine.
I burned one board only connecting 12V to 5V port with the same behavor you described but that was my fault.
Cheers,
Nils
Thanks for your reply. I am worried this is a problem with my project design, since like you said this should not be an issue. In trying to troubleshoot I just destroyed another Nano Every - this is becoming an expensive problem!
Would anyone be able to look at my design and let me know if you see a problem? The project is to control three pet feeders. Each feeder is a 28BYJ-48 stepper motor and UNL2003 driver. (I am using the 12V version of the motor not the more common 5V version). These 12V motors run OK on 9V so I am powering the project with a 9V wall adapter (Adafruit product 63).
The project includes an Adafruit DS3231 real time clock. The sketch is programmed to operate the feeder at specified times, or to run the feeder manually with the pushbuttons (I could post the code if it matters but this seems like a hardware problem). The Fritzing diagram shows a Nano V3 but I'm actually using the Nano Every.
Apologies for the very inelegant Fritzing. I am very new at this.
Does anything look problematic about this design? Thank you for any feedback!
Your push buttons are putting unregulated 9V directly into the input pins!!!!!!!!!!!!!!!!!!!!!!!
Do not connect the buttons to the power supply. Set the inputs to INPUT_PULLUP, which enables the internal pullup resistors, then have the button connect the input to ground when pressed. That way you don't need any external pullup or pulldown resistors. You will need to modify your code to recognize the inverted logic of the button inputs.
Thanks so much for this reply. It never occured to me til now that was a problem, since that's how I learned to configure buttons from all the tutorials, with an external resistor. Except that ordinarily the + to the button would be coming from the +5V pin of the Arduino. So do I understand correctly then, that this is an OK to way do buttons if the + is from the +5V, but not with an external power supply? I will read up on the INPUT_PULLUP configuration of give that a try. Thanks a million.
It would be OK if you wired the buttons to the +5V of the arduino, the problem comes when you try to put more than 5V onto an input pin.
The Nano Every does have the option for INPUT_PULLDOWN I believe, although I've never tried it.
With reference to the OP, I've also tried using an external supply along with USB connected. In my case, the external supply was 5V connected to VIN. Note that at the time, the specifications had shown a range for the input power being 4.5V-21V ... now its just stated as 21V (limit). After having some issues, I've decided to connect the external 5V supply to the 5V pin and use just a simple jumper for disconnect when the USB is connected. Found this link to be helpful.
Looks like the single nano every (with and without headers) has been removed from the store ... now only available in multiples (pack).