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Say I buy a device that requires 25 volts to function, but I want to control it using my 5v arduino. How would I go about powering/controlling higher voltage devices?

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It depends on the 25V device you're writing about. Post a link to it, please. – Nick Alexeev Mar 21 '12 at 22:50
this is mostly a theoretical question.. using an arduino, how would I power a device that requires a much higher voltage than the 5v supplied by the arduino? – tester Mar 21 '12 at 22:52
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Are you actually wanting to power it? What is the current that would need to be provided? Or are you just wanting to control it via a relay or something? – Kellenjb Mar 21 '12 at 23:53
@Kellenjb After thinking about this for a while, I just want to control the flow of a 12v device using the arduino – tester May 10 '12 at 19:08

4 Answers

up vote 2 down vote

Yes it's possible, and it's usually done by step-up (boost) converters. These converters are based on the principle that inductors react to sudden changes in their current with a high voltage. So, an inductor is put in series with the supply and switched (here the name Switching Mode Power Supply, SMPS) between a short circuit and the load. When the switch opens, the inductor has to discharge the stored energy and it does that creating an opposite voltage than the one it's charged with.

Another efficient way is also the charge pump, where capacitors are charged at the supply voltage (5V in this case) and then put in series with the supply rail to generate the higher voltage. It's commonly used to double voltage, but different ratios are possible.

All these circuits create a pulsed output voltage; it can be filtered afterwards to give it a more stable shape if required.

(Sorry for the quick answer, got to sleep : tomorrow I'll make it better but meanwhile look at the links)

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up vote 2 down vote

An example of the answer by Petteri Hietavirta can be seen at the link.

Yenka Model to play with.

enter image description here

Opto-Isolator is a safe way to go to avoid frying the Arduino.

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That controls the higher voltage device, doesn't power it. – Federico Russo Apr 18 '12 at 6:09
tester said power or control – rdivilbiss Apr 19 '12 at 22:39
As I understand it he wants to power and control it – Federico Russo Apr 20 '12 at 6:16
up vote 0 down vote

If you have correct voltage supply available for the device you want to control with Arduino, check optoisolators.

With that your Arduino should be safe from high voltage but still able to control the device.

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That controls the higher voltage device, doesn't power it. – Federico Russo Apr 18 '12 at 6:10
Why the downvote? OP said specifically control. – insta Aug 27 '12 at 23:12
up vote 0 down vote

You can also boost your voltage by external circuit designed for specific values as @clabacchio said. I think this link will help you much.

And this video tells you a story of an engineer and his journey to find the best voltage boost for his needs.

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