I have an Arduino Pro Mini 3.3v in a robot. The problem is, the Mini would automatically randomly overwrite the uploaded sketch with the default blink sketch... And this is becoming quite a problem.

I have connected the Arduino to a L293D Motor Driver and the Arduino gets its power from the motor driver only. It will work just fine, but randomly will reset to the blink sketch...

Please help

P.S- It automatically corrected after a while

  • 1
    I think you are seeing the bootloader, not the blink sketch. – Gerben Nov 10 '16 at 13:03
  • @Gerben whatever it is... My sketch isn't running! – YaddyVirus Nov 10 '16 at 15:13

The most obvious cause for a reset is pulling to much current from the Arduino. I have never heard of an Arduino downloading a new sketch to itself. Is it possible you are seeing the board booting up and flashing the LED as its doing so?

If you are getting the power from the motor driver its possible you are either giving the board noisy/dirty power or the motor is pulling to much current and depriving the board of power. I would run them on separate supplies (with a common ground) to avoid this.

| improve this answer | |
  • I am providing ~18V (2 9v batteries connected in series) to the Motor driver. The motors can easily run on single 9v battery. I am clueless about what to do – YaddyVirus Nov 10 '16 at 12:45
  • Thats overvoltage, not over current. Connect the batteries in parrallel – Dat Ha Nov 10 '16 at 12:48
  • The board may be resetting itself due to the overvoltage. Running the batteries in parallel should eliminate that as a suspected cause. – Kelly S. French Jan 31 '18 at 14:54

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