Basic Circuit Diagram


I am currently doing a project and it seems that I may have blown my Arduino Nano (or maybe not). The power LED of the Nano was still on and I believe the L pin blinks once every time I press the reset button.

I wanted to use 4AA alkaline batteries to power my project. The servo is a continuous servo rated for 4-6V and 15-200mA from Parallax. Given that the Nano runs optimally when powered at 7-12V, I decided to buy a step-up converter (adjustable output voltage). It looks like this although I bought it elsewhere:


When I tried to test it with the servo running, my Nano stopped working after several seconds later. Did I wire them up wrongly? I also measured the output of the step-up converter when it was running with a voltmeter between the two terminals of the step-up's output. Would it be possible to short it that way?

Appreciate any help I can get. Thanks


It would be best if everything ran at the same voltage. (And it is necessary that everything uses the same ground.) Which is possible as there are 5V Arduino boards. Interestingly, the Arduino nano, according to this schematic, runs at 5V.

In order to use the Arduino Nano at 5V, instead of using VIN / Pin 1, you should be able to skip the Arduino's 5V regulator and use +5V / Pin 4. But this must be a regulated 5V power source.

Now, why are you having problems controlling the servo?

It is difficult to tell, but your boost switching power supply negative input may not be directly connected to the negative output. With out a common ground, it may be difficult to create the proper signal to control the servo.

To be specific, if the ground or negative side of the servo power supply is not at the same potential as the ground or negative side of the Arduino power supply, controlling the servo may be difficult at best and at worst you could burn something out on the servo or Arduino.

To check, measure with a volt meter to see if there is any difference between the boost switcher negative input and negative output.

To solve this problem consider using a USB power supply plugged into the Arduino Nano and powering the servo off the 5V at pin 4 of the Nano. Or, keep using your 6V battery and 6V to 9V boost switching power supply. Connect this as you are to VIN Pin 1. The Arduino Nano's 5V power regulator should kick in and provide 5V at pin 4.

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  • Hey thanks for answering! I used the step-up converter in hopes that it could regulate a constant voltage around 7-12V and also avoid the Nano from resetting when the servo is powered. I didn't want to set the Vin at the lowest possible level to keep it from happening. I don't have much problem with using the servo if the Arduino didn't blow up. Also, I recalled that the Arduino cant supply enough current to the servo. The device will need to be portable as well. I think your explanation with the step-up converter may help. I will check on it when I can. Thanks a lot for the help! – TraineeGuy Sep 23 '19 at 5:20
  • I think your servo is small enough such that it can be powered through the Arduino's voltage regulator. But you are correct to concern your self with the possibility of the servo pulling too much current and resetting the processor or, worse, burning out the Arduino's voltage regulator. The most common problem I have seen in questions here is not having a common ground between the servo and the Arduino power supplies. If the above answer eventually works for you mark it as correct. If not, add to your question so that others may be able to provide better answers. – st2000 Sep 23 '19 at 17:42
  • I had a friend to check it for me and he said that the grounds are connected appropriately. Still was not too sure why it blew up but appreciate the help. Got the arduino working now as well! cheers! – TraineeGuy Sep 30 '19 at 11:12

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