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i recently started using Arduino uno , but to my despair , the ground pin , without which i cant do any project (or can i ) , so i thought of a possible solution , what if i could program the board to make a pin act as a ground , so what to do straight 2 questions , what to do to convert any pin into ground or can i ignore using the provided ground pin . i have already tried fixing the pin but it cant be fixed because a detached pin has got stuck into it

  • There is more than one ground pin on the arduino. Just use another one. You can make a pin into ground, that’s what happens when you write a pin LOW, but only for a very limited amount of current. So it depends on what you want to do there. But really, just use one of the other ground pins. – Delta_G Jul 27 at 17:31
  • thanks for help , but can u help me furhter , i am a total starter , where is this second grnd , and actually i just connect my laptop for v+ – shaurya mittal Jul 27 at 17:32
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    there are 5 ground pins on Uno. two between Vin and 5 V. one next to pin 13 and two on the ICSP headers. so what happen to the ground pin? – Juraj Jul 27 at 17:37
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    Look at the board. The pins are labeled. You should be able to find them. – Delta_G Jul 27 at 17:46
  • yeah ur comment was useful , i found all of then , but still as an alternative , if i ever mess up with my board , can i convert any pin into ground – shaurya mittal Jul 27 at 17:47
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Can I convert any pin into ground

Any of the digital outputs can be set LOW but there is a limit on how much current they can sink,

This makes this approach unsuitable for most use cases other than charlieplexing LEDs and similar low-current applications.

It would be better to

  • use any of the other ground connections.
    • two between Vin and 5V
    • one between Aref and 13
    • one on the 2x3-pin ICSP header for the 328
    • one on the unlabelled 2x3-pin ICSP header for the 16U2
    • one in the power jack
  • replace the damaged header using solder-wick and a soldering-iron.
  • solder a wire from a suitable ground pad on the PCB
    • e.g. from the ground pad for the 2.1mm power connector.

The ATmega328P data sheet says

Although each I/O port can sink more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed:
ATmega328P:
1] The sum of all IOL, for ports C0 - C5, should not exceed 100mA.
2] The sum of all IOL, for ports B0 - B5, D5 - D7, XTAL1, XTAL2 should not exceed 100mA.
3] The sum of all IOL, for ports D0 - D4, should not exceed 100mA.
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed test condition

So no more than 20mA from or into any single pin over a long time. And no more than a total of 100 mA from or into a group of pins.

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