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Control led strip light with arduino from 12v? Answered

Hello, I would like to control my 12 volt strip light (not RGB) with an arduino and also use a potentiometer to be able to adjust the brightness manually.  

However I am afraid to fry my arduino board with 12v directly as it will fry it and I also want to be able to use higher voltages in the future but for the time being only 12v volt will do.

I don't really know what to use to control high voltages and current so as to be able to control it.  My choices are relays but most are from 220v to 12v and can only be on and off so very difficult to control brightness.  

Another choice would be to use my potentiometer but again I don't know how to control it and especially about the value such as 10k for example.  

Then there is the use of transistor such as MPN and NPN which I don't remember how to use.

It has been at least 4 years since I was in electronics and now want to get back in so as to create awesome things but I need to be sure that I am safe and for other people as well.

Thanks again for you help.


I would look at using a transistor like the TIP142. It would have enough current to drive the led strip. The potentiometer can be read through the analog pins on the arduino. The values can then be used to control a PWM pin to vary the brightness of the LED strip.

Excellent will try this one out and buying the parts that I need.


1 year ago

Just learn how to use transistors like MOSFETs and BJTs (the most common types) There are plenty of tutorials online and on youtube. Afrotechmods has a good vid on that.

Hello, yes I did check them and Afrotechmods are awesome, I am also looking around for any new ideas.

Why do you want to use an arduino? Why not use a fairly cheap dimmer?

If the only thing that you want to do is dim the brightness, a cheap dimmer is definitely easier, cheaper, faster, and probably better.

Try this dimmer, I bought it today, and I'll think it should work: http://www.ebay.com/itm/universal-dc10-60v-pwm-hho... It can handle more than 8 amps

Nice one, I never thought of this and already bought one. I want to try more DIY things in the near future so I want to learn at the same time which is why I am asking.

I also want things to be much smaller and where I can adapt + the arduino will allow me for more creativity in the near future.

If you want to stick to the Arduino do yourself a favour and get a breadboard and beginners sortiment in electronics parts like LED's, transistors, resistors, switches, mosfets and so on.
These sortiments are available through Ebay and all sorts of variations and part counts, often together with a breadboard.
Gives you more flexibility and room to play ;)

No need to I already have the parts in hand and currently relearning how to use them properly. I am just asking out what are my options and what I can do as I might have an idea but others will have more and still much better one.

Best IMHO is to look online what others did and how.
Take the best picks or combine things you find.

How many amps will the LED strips draw?

Smaller? Try this: http://www.ebay.com/itm/LED-Dimmer-Controller-With... I bought six of these, and they work really well. They can also prosuce a strobe effect.

The only downside is that you have *only* 8 different dimming brightnesses. For a big project, I'd use the other one, but if you want to save money, and for small projects that don't need such precision, I prefer using this cheap one.

I should be paid for this free advertising!

A very simple Google search gives about 50 usable hits on the first 2 result pages - both for Arduino and without it. ;)
But using a microcontroller for this task is like using a sports car just to get 12V from it's alternator...