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Arduino gets heated up

Thread starter #1
I am doing a project where I am using arduino and arduino motor shield. When I give 12V to motor shield, arduino gets heated up. I am afraid it may damage my arduino so any suggestion, i will be glad to receive it.


Well-Known Member
You need to give more information.

You say the Arduino gets hot, think you mean its the Arduino micro board , the motor board will get warm depending on the current its handling.

Which Arduino board are you using, eg Uno, Mega and if they are Clone boards , links to their exact specifications.

How are you powering the Arduino board, via USB cable or external PSU at what voltage ?

What motor have you got connected to the motor shield.

Does it get hot when no program is running or only when you run your motor program ?
Thread starter #3
Thank you for replying
I am using arduino uno and the motor shield is mounted on top of it.
Arduino was powered via USB cable
12V was given to the motor shield terminal to drive 12V dc motor
Arduino gets hot only when program is running


Well-Known Member
The motor shield can get hot depending on the load / current taken by the motor.

Do you know what the current rating of the motor is ?

Does the the motor speed vary correctly as you alter the PWM rate.

If its the Uno that is getting hot , what area is heating up and how long does it take, a few seconds or a few minutes ?
Hot meaning you cannot keep you finger on it for more than a second.

Anything else connected to the UNO other than the motor shield ?

Post /Insert your code here in case you have a problem there.
What power supply are you using?

I was recently helping out on an education project. The school had a 12V DC power supply but it fried the Arduino (micro in this case). Measuring it with a DVM it was outputting 11.8V dc but with 4V rms ripple! Peak voltage was a lot higher than 12V and this fried the regulator and then the IC. :(

In that case i rectified the problem by simply buying a REGULATED 12V supply.
Thread starter #6
Power supply is given from breadboard

I have never try to vary the speed
Heating area is beneath where there is two capacitor where 25V 47 is written on it
Its getting hot gradually
Nonthing is connected with motor shield
Attached file is the program code that i am using


breadboards don't have an inbuilt supply....

is it battery powered? or a lab power supply to the breadboard or a plug adaptor to the breadboard??
Do you have a make & model for the power supply. They can vary in quality quite a bit.

An overheating Arduino come down to a few possibilities, lets go through them:
  1. Defective arduino board - unlikely unless you've got a cheep knock off from Ebay?
  2. Defective motor shield - unlikely unless again you've got a cheep knock off?
  3. Motor shield installed the wrong way around. Not sure if this is possible but if it is can you confirm the power pins are lined up correctly?
  4. Power supply output is no accurate or has ripple, we'll see when you confirm make and model
  5. Power supply is non-isolated and you have the board connected to USB when powered from lab power supply. There can be a ground difference between laptop 0V and power supply 0V. Is lab power supply output isolated?
  6. power supply is connected to the wrong inputs? 12V supply should be connected to Vin and not 5V.
  7. Accidental short circuit on the arduino somewhere, unlikely if you haven't connected anything yet and points (1) and (2) are ok. Please check for possible shorts?
  8. Excessive current draw on outputs, could any bit of circuit be pulling outputs to ground with no current limiting resistor? (example, LED on output with no current limiting resistor or a switch to ground but with I/O configured to output accidentally)
  9. excessive voltage on inputs, could any bit of circuit be pulling the inputs to high voltages? (example pull up on inputs but incorrectly connected to the 12V power)
Heating area is beneath where there is two capacitor where 25V 47 is written on it
The only part of the Arduino schematic with 47uF capacitors is part of the 5V regulator circuit.
If this is getting hot it suggests your either drawing too much power from the 5V or your supply voltage is too high.

Are you using the 5V produced by the arduino for anything else? a sensor, switch some lights?
Thread starter #11
No I am not using anything
Arduino was powered via USB cable and motor shield is mounted on it
I am just using 12V dc motor connected at the terminal of motor shield
I do wonder if its an issue with ground levels, i've blown up programmers like that before.

Please answer all points in post 10 to help us work this out.


Well-Known Member
Some photos of your boards, power supply and motor might help us see your problem.

The metal case of the Unos USB connector, have you put some gaffer tape or similar over the top of it to prevent it shorting against any shield.

What happen is you load the Uno with the Blink example, motor shield still plugged in, then apply your 12V to the shield, no motor connected.
Does the Uno get hot , if not, does it get hot if the motor is then connected ?


Well-Known Member
Most Helpful Member
What circuit?
Thread starter #16
I have not yet solve the problem regarding heating up of arduino when 12V is given to Vin to arduino shield.Can anybody please help me


Well-Known Member
Most Helpful Member
Can anybody please help me
You have to help us by answering all the questions you have been asked in previous posts if we are to help you :rolleyes:


Well-Known Member
His motor shield is powering the uno without a link or something to see witch one the op is using there's no helping him.
I can only talk for myself but I have one that has jumpers that you can set to power the uno with Vin you hook it up setup wrong and it over heats the uno regulator.


Well-Known Member
I have not yet solve the problem regarding heating up of arduino when 12V is given to Vin to arduino shield.Can anybody please help me

Looking back at your posts, the only facts you have told us it that you are using an Uno , Motor shield and a 12v psu.

Please give us exact info - Is the Uno a genuine Arduino or a clone, if a clone please provide a link to the actual board

More importantly, the Motor Shield, is that genuine Arduino or a clone, if a clone please provide a link to the board you have.

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