Arduino Won't run code when connected to a power supply

Using Arduino Project Guidance
1

I have an arduino uno quadcopter project powered by a 3 cell 11.1v lipo with a diode in between. It worked fine before but this issue has arrised after a crash. I have a 3.3v imu powered from the arduino and a receiver. When the arduino is connected to my pc via usb and powered by the lipo it run s the code perfect but as soon as you disconnect the usb it no longer works, The motors do not receive any signals and an LED I have connected which usually flashes indicating startup just stays on . Pressing the reset pin does nothing either. I know this issue has been discussed and I only make a new post as I have tried the following solutions on the forum :
Buck converter from power supply to arduino;
Capacitor from reset pin to ground;
resistor from rx to ground;
connect tx to rx;
There are no Serial commands anywhere;

2

YMFC_schematic.pdf (138.1 KB)

This is the schematic however it worked before with the same code so I don't think it's a firmware issue

3

Does your sketch have a line in it something like this ?

while (!Serial) ;
4

Nothing like that

5

Please post your sketch, using code tags when you do

2 Likes
6

@kocokm
You will need a DMM/Multimeter to do further debugging. Do you have one?

1 Like
7

Yes I do

8

sketch_nov6a.ino (16.6 KB)

9

With the batteries connected, check the voltage at the Uno Vin pin and the 5V pin.
Vin should be 11.1V and 5V, 5V.

10

And if it is so that the voltage is correct what would be the next debugging step?

11

You said pushing reset had no affect and it worked before with the same code, so I'm not sure what the next step would be.

Maybe loading some test code that prints debug info to the serial monitor.

12

Is this an assumption or have you actually checked?

13

to be fair after testing the 5v pin gives a voltage reading of 0.01v on the multimetre

14

to be fair after testing the 5v pin gives a voltage reading of 0.01v on the multimetre.

Then there is no point in running test code!
However you must be doing something wrong. If there is no 5V then the LED would not be lit.
Do you see burn marks on the Uno?

15

no burn marks but the code runs when connected to usb and the lipo?

16

What voltage did you measure at Vin?

17

11v

18

Then I suspect that the 5V regulator has burned out.
Easiest thing to do is just replace the Uno.

1 Like
19

Thank you for your swift replies it is much appreciated , hope you have a nice day. At least nicer than my 5v regulator