Arduino USB port causing overheat after I attached 12v to the VIN pin

Other Hardware General Electronics
1

This problem is quite urgent as it is needed for a project!

I powered my arduino nano board using 12v soldered to the Vin and Ground pin (using a switch as well). When powered by this battery, both the power led and the initial blink led both work and don't overheat. I soldered these components directly to the board.

However, when I take the battery out - to then update/upload my code, the USB port isn't recognised and the power LED heats up. The blinking LED doesn't turn on.

I then un-attached the USB and tried to power it again with the 12v and both LEDs still work fine.

Have I somehow messed up the USB port by soldering directly onto the board? Is there anyway I can fix this?

Note:
Battery = A23 12v battery
Switch = Standard toggle switch
(I tried both of these to power another Arduino nano board and it worked without problems as I can still use the other to upload code etc)

I soldered the 2 necessary GND wires to the corresponding GND pins, the 12V+ straight to the switch, and the 'application' straight to Vin of the Arduino nano board.

I also have a functioning Max30102 soldered and was about to upload code to run it before this happened.
The code for this sensor works fine - I have tried with another arduino board - and both the USB ports on my laptop are undamaged.

2

Well, you have clearly done something very wrong in the wiring so rather than attempting to describe it we need a diagram (can be hand-drawn) of how you think you have connected everything and some photos - taken in full outside daylight but not sun, with perfect focus and detail at least 1024 by 768, not in a dark room - of your setup.

3

Hi,

I have attached a very rough sketch of the connections that I have done. Hopefully it is clear enough that you understand what I have done.

Thanks for the response!

DrawingOfConnections.png
DrawingOfConnections.png902×1032 209 KB

4

Hi,

So I have tried attaching the power with an arduino nano with header files and it does the same thing!

It wasn't a soldering issue, it's something else. Even when the power isn't flowing, the arduino nano still heats up.

For uploading code do you have to completely remove an external source of power? Or is it the way that I have soldered my power supply?

Thanks ^^

5

Hi!

For anyone who has had my issue:

Check the wires and soldering connections (they were fine in my case),
Check the battery rotation (fine in my case again),
KEEP THE POWER SUPPLY ON WHEN CONNECTED TO USB (I TURNED IT OFF, WHOOPS).

Turning it off is a no-go, I don't exactly know the reason but it was a rookie mistake.

Thanks!

6

Your switch suggest that you connect V-in either to 12volt or to ground.
Can't do that if you connect to USB for uploading.
Connecting V-in to ground will cause current from the USB supply to flow backwards through the 5volt regulator and releasing the magic smoke. Remove that ground line.

12volt is usually bad for a 5volt Nano.
The regulator has to drop 12-5= 7volt, wasting more than half of the battery power, and possibly overheating it.
Could be lucky there, because the (too weak) A23 battery can't provide the current to run a Nano anyway.
Better think of another way (lower voltage, higher current) to power the Nano.

Are you sure the I2C module runs ok with 3.3volt on V-in.
V-in usually is used for the input of a voltage regulator, which needs more than 3.3volt for a 3.3volt chip.
Product links please.
Leo..