Beef Up Your Arduino Power





Introduction: Beef Up Your Arduino Power

Ever been running something on your Arduino, and the project malfunctions because of a drop in power?

I experienced this with a project called the "Pong Clock".

Under normal circumstances, the Arduino can power the display without major issues.
I found however that when I used the "numbers" mode which puts very large numbers on the display, the number of LEDs that were on all at once would cause the clock chip to stop communicating with the Arduino - resulting in a time of 00:00.
It would sometimes trigger this in the "Random" mode too, causing the random mode display to loop over and over between the correct time and 00:00.

I finally tracked the problem to insufficient voltage. You can't put 5V into a 5V regulator and expect good results.

So I plugged in a 9V power adapter, and all the problems went away.
But it created another issue.
The 5V regulator on the board would get EXTREMELY hot, risking damage to the regulator, which could have resulted in damage to the board.

Fortunately, these regulators (the 1117-5 or "5V 1117") are easy to find and cheap on EBAY. I got 10 for $1.20 Canadian with free shipping.
These regulators can be connected in parallel without extra components.
I simply bent the leads and tab straight down, and soldered it on top of the original 5V regulator with a touch of heat sink grease between them.
At the time of this writing (May 24, 2013) these are item number 130750914480 on EBAY.
They still get hot enough that you don't want to put your finger on them very long, but this drastically reduces the chance of failure and reduces the heat quite a bit when using an external supply over 5V.

I did want a heat sink, but didn't want to solder anything to the live tab of the regulator.
My compromise was to add a heat sink to the top of the upper regulator with regular heat sink grease.
Then there was the issue of how to hold it there. The USB jack shield and the 16MHz crystal were perfect mounting points.
A penny, some heat sink grease, and a bit of solder is all you need.
You may need to turn up your soldering iron a bit to get the solder to stick to the USB shield. I found 350 deg. C worked for me.
Now I have a great copper heat sink - and I'd like to say it didn't cost me a penny, but as you can clearly see, it did!

Secondary Addendum - The best way to reduce / remove regulator stress is to use a 5V supply to begin with, and power the project and run a line back to the Arduino to power it.
When this isn't an option, use power adapters between 6 and 7.5 volts. The more voltage the regulator has to absorb, the hotter it gets. Reducing input voltage dramatically reduces the heat the regulator generates.



  • Spotless Contest

    Spotless Contest
  • Space Challenge

    Space Challenge
  • Science of Cooking

    Science of Cooking

We have a be nice policy.
Please be positive and constructive.




run your 12V to the shield, and put a 5V regulator on it and feed that 5V back to the processor.

Thanks for the tip! I have never heard anyone suggest that depending on what you have added that an std. external 12 Volt wall wort could create an issue.

I have had a problem with a digital temperature display just dyeing on me after several hours. I am using a 16 x 2 LCD display with back light. I recently moved it to a new location and for some reason picked up a 5 Volt USB charger that I think came from my tablet used through the USB port. Rated at 2 Amps. I just realized that since I moved it and used the 5 Volt supply I have not had a problem in weeks! Now I think I know why. I can imagine the trouble I would have gone though chasing this kind of random failure on future projects because

"If 5 Volts is good 12 Volts is better!" NOT!!

Thanks for answering my problem and for preventing me from chasing ghosts in the future. Kudos to you sir. LOG (lazy old geek)

Would the below description be a highly regulated (voltage/heat) choice?

12Vcomp-fan<5V_Regulator(W/ heat sink)<then Arduino power

Where: fan feeds from 12V which then feeds the 5Vregulator (steps down) which then feeds the Arduino.

Another question: How efficient would a peltier be if I used the heat generated from the regulator to run a small fan for cooling. Given the current needed to run the small fan isn't greater then the output of the peltier.

Your best bet is to simply use a good 5V source.

In most cases, just power your project off the 5V source, and run power back to the microcontroller from there, rather than trying to power the project through your on-board regulator.
For most people here, adding a peltier would increase the current draw of the project by a factor of 10 or more, with the fan itself representing a negligible part of that.

TY,I was hoping by creating some heat more in turn create more energy but it seems ohms law still grasps that thought or regeneration.

watts/heat created is almost always a loss in power.

I would like to add as a side note that NOT ALL REGULATORS can be hooked up in parallel like this. Always do your research before attempting this. Also, it's usually a better idea to simply get a higher current regulator in a situation like this. I did it this way because (1) I could, and (2) these regulators are extremely common and dirt cheap, and (3) I had to get the regulators anyway for another project. These are handy little devices to have for any project that requires a steady 5V that you want to power off a 6 or 9 volt pack.

One thing I've started doing, instead of taxing the regulator on my 2 Duemilinova's, Uno, & MEGA-2560, when using a 12V source (off a slightly modified ATX supply), I use a heavily heatsinked LM7809 regulator. (TO-220 case, Heatsink is 3" X 1.5" X 1/4" Thick).. The sources of the 7809's? I went through a LOT of my old computer gear, boards, and found several old 8-bit & 16-bit SoundBlaster cards had the 7809 as a regulator for the amplifier.. I've used them for Arduino projects, and charger step-downs for an old Sylvania Netbook (7", ARM based) and a portable DVD player, off the same ATX supply.) Whenever I whip-up an arduino circuit, I'll use an old 3.5" floppy power connector, to run a mini-molex plug from the supply, to 4 pins on a breadboard, plug the regulator in nearby, running wires from GND & +12V, then a pair of sacrificed pin leads to a coaxial connector. This way, I can run servos off the +5V on the supply, without overloading the +5V regulator on the Arduino.

A better plan is to take the 5V line off the power supply, and drive the 5V line directly on the board rather than using the 2.1mm power jack.
Better yet, if you have a heavy-draw circuit, put the 5V into the circuit itself, and run a 5V line back to the Arduino to run it.

Although, kudos for a great idea. If I had to make 5V from a 12V battery, this would be the way to go. Reducing the voltage going into the 5V regulator dramatically reduces the heat it produces.

I've had the 7809's get warm, going from 12, down, when charging devices. (usually charging things with a 7.2V battery, but also reduced when going through the circuit to be charged.) (Hence the big heatsinks I've added.) I'm still tinkering with the idea of possibly bending the +5V pin out from the Ethernet board, and hard-wiring a line from the +5V output from the ATX supply.. (letting that supply the 3.3V regulator.) But, seeing the schematic of the more recent R3 ethernet shield, It looks like it has more than one, 1 going through the SPI plug.)