Controlling high power LED's or DC motor for that matter, you can make a circuit with a MOSFET (TIP120) on your breadboard. Many examples can be found online. For fiddling around this can be your weapon of choice. When used inside actual object / projects you need a solid solution, made by people who do not fiddle around :)

Step 1: Problem & Solution

I needed to PWM (Pulse Width Modulation) a Highpower LED (60V): I needed tot dim the LED ;) And I did not want to solder a custom proprietary crap-ware piece hardware.

You can buy many off the shelf boards that will do this for you. A simple circuit with a TIP120, 555 timer and a potentiometer will costs you no less then €5,-

Step 2: ​Ready Mades

Personally I like to use off the shelfs components. Pure for the fact, that if it's broken, you plugin a new one. I've made my faire share custom etched PCB's. In this world you can find enough components that would work within your project. If it's a USB relay, PWM dimmer, motion detection etc.

Step 3: ​Our Tool of Choice

DX Jtron PWM DC Motor Speed Controller - Groen ( 15A / 6 ~ 90V )


Obviously you can find many more:



Most of these circuits use the same layout, just spot for the 555 timer.

This works only when you manually want to control the pitch via the potentiometer. But that's not our goal. We want our internet of things to control our life, right? Our Arduino needs to control the Potentiometer. Again you can buy a 'digital potentiometer' chip for your Arduino. The problem is you need to solder again, which is not our goal :)

This circuit has everything we need. It can PWM up to 90 Volts @ 15A. More that you need, so that's a good thing. The 555 chip (timer) makes this board do it's PWM. When you strip it out, you can feed the Arduino's PWM into the board. Bob is you uncle!

Step 4: ​Get Dirty

Take a good shap, edge cutter made out of adamantium, and simply remove this piece of obsolete hardware. Now you have a naked module that's not working. But you did not break it, you kinda jailbroke a PCB

Now can feed the circuit with our own PWM that we control. Awesome!

Step 5: Removed 555

As you can see it's gone. You can see in a white diagram in the board. Representing a 555 chip. But the actual chip that we removed 'looks' different and is positioned different.

Also note the solder points. We need to figure out which one is the output. Looking @ the 555 layout, they don't correspond.

In the image I have made markers where to put the arduino Outputs.

If you hook up a PWM port (9|10|11) and the GROUND from the Arduino to these points. You can Dim the whole world. :)

Good read from the Arduino site:


I did not keep my promise, for not soldering stuff. But every monkey should be able to solder something on a PCB.

Happy hacking.

<p>Do you know which pins would be for the ground and pwn on this one? (Seems to use a proper 555 timer, chip says NE555P)</p>
<p>You can always backtrace ground with a multimeter. PWM should be on the opposite.</p>
<p>That's better 20A :)</p>
<p>Hi, how did u know there IC is 555? I have one same like this, but there no show code of IC (not SMD)...</p>
<p>Because these circuits depend on a 555 timer to enable the PWM. So the 555 may not have a nice logo or other markings on it. But it can not hide itself :) The other components are clearly no 555 timer. I'm 99% sure it is a kind of 555.</p>
<p>Hi, well... there is your photo, pin GROUND is right, but here is photo original of 555 is left... I don't understand...I think is not 555 ...</p>
<p>But anyway, working perfect with arduino instead dead original IC. :D</p>
<p>Yeah! Rockon! :)</p>
<p>The layout could be mirrored. And perhaps there are more variants of the 555.</p>
<p>Very cool. Thanks for sharing this.</p>

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