LUX - an External Power Button





Introduction: LUX - an External Power Button


It's a lazy afternoon, and you sit down to turn your computer on, you either: a) you have to bend down and press the power button, or b) you have a laptop - this isn't for you.

Especially where my (desktop) computer is located; under my desk and out of sight; bending down to press that power button is a pretty annoying task: that's the problem, and this is the solution:

LUX - the external power button

Now, I know i'm not the first person to make an external power button, but I still think it's pretty darn cool and it's the design of mine that sets it apart from the others.

For the record, this requires no programming, just some soldering.

This instructable requires you to change the wiring inside of your computer, if you are not careful when doing this you may break your computer. Make sure your are comfortable with doing this before beginning the project.

The main idea behind my design is that I have a cube (yes, a cube), where the top part is separate from the base, and where the two connect there is a push-button which turns on the computer, and an LED just for the cool factor! (right?). How is this possible you may ask! It is simple really, it is just like instead of the signal coming from the button on the front of your computer case, it instead comes from LUX; same with the LED- instead of the power going to the LED on your computer case, it instead goes to LUX.

Step 1: Tools & Materials

This ain't no advanced project ill tell you right now, it is just some simple woodworking. If you can nail a nail and cut wood then you will be fine.


Wood (of course!) - I used a single strip of 30x11x1800 and for the larger surface areas I joined 2 cuts side on side.

Pushbutton (a large, breadboard style one preferably)

LED (mine was an RGB LED - just for fun)

100 ohm resistor

Hot Glue


Female USB port

Female header pins

Wire with male USB connector on one end

USB extension leads

Wood glue

Blu tac

Wood putty (optional)







Hot Glue Gun

Soldering Iron

Step 2: Preparation

Make your measurements, if you are lazy and can't do math here are my measurements:

4x 60x30


1x 12x12x35

Don't forget to leave space where the saw will cut away (usually around 5mm for me) and take that into account when marking your measurements out.

This can all be cut from a single 30x11x1800 strip of wood.

Step 3: Assembling

(psst, all measurements are in mm if you didn't know!)

1. Join 2 60x30 pieces together using long nails and wood glue to make a single 60x60 - do this twice.

2. Drill a hole in the middle of a 60x60 piece big enough for the button part of your chosen pushbutton to be inserted into.

3. Attach the 4 - 49x30 pieces onto one of the 60x60 pieces you just drilled, making sure that the pieces each have 1 end touching the other pieces side.

4. Drill a hole at the top of the 12x12x35 piece big enough so that the legs of your chosen LED can fit through.

5. Nail the 12x12x35 into the centre of the other 60x60 piece. (best to nail it from the bottom up)

You should now have 2 pieces: 1 box sort of thing and a bottom piece with a pointy bit sticking out (refer to photos if you don't understand my terrible description)

That is all the woodworking done, now all that is left to do is the soldering and wiring.

Step 4: Soldering

Go grab your pushbutton, your led, some cable and the USB connector, why the USB connector you may ask?, seeing as a standard USB has 4 pins, Data +, Data -, VCC and GND, I thought these would be perfect for LUX, but don't be confused, this isn't meant to be plugged into a USB port or else it won't work. Using USB too, it makes it easy to extend the wires distance using cheap USB cables rather than resoldering new ribbon cable etc to it.

1) Get the end of the lead with the Male USB plug on it. Before we start soldering we need to determine what colours are where on your specific USB lead. By this I mean which colour wire corresponds to the position of the tab on a USB port.

2) Get a cable with a USB male connector on one end, and a spliced cable on the other end. Solder 2 wires to the LED's + and - (edit - I forgot about the resistor, you will need to connected a 100ohm resistor to either + or - on the LED - not for the pushbutton however), and the other 2 to the pushbutton. The pushbutton would sit on top of the piece of wood and the LED would sit on the side (facing forward), with it's legs going through the hole you drilled in the top. (confused? refer to the pictures) Make sure to take notes of what colour wires and connected to what.

3) Hot glue those wires down onto the base so that you don't see then and they are held securely in place.

4) Now, get your female header pins and your female USB port + some extra wire. You will need to open your computer case and get to the place on your computer's motherboard where the wires for your computer case goes.

Safety Check! - Have you unplugged your power supply and make sure that it is discharged?

You will need to solder 2 of the female header pins to the + and - of the LED, this needs to correspond to what colour you used. Do the same for the pushbutton with 2 separate female header pins. Not to worry if you get this wrong the first time, the computer just might not start up.

Step 5: Plugging Stuff In

So you have your 2 distinct sets of wires, 1 for the LED and another for the pushbutton. Where do these go you may ask? They go into a special area on the motherboard that is reserved for these connections. They are normally grouped with other cables such as a piezo speaker, a hard drive LED and even a reset switch. What we will be changing is the commonly called "PWR LED" and the "PWR SW" (power switch). The polarity of the switch doesn't matter (because it's a switch) but the LED's does, but it won't blow up if you get it wrong. (just do a bit of trial and error to get it right). After that, the LED and power button on the front of your computer case won't be functional but don't fear! this is 100% normal and expected. What should be happening is the LED on LUX should be lit and pressing the pushbutton should act as if you were pressing the one on the front of your computer! If this is what happens then congratulations, you just made LUX.

Step 6: Q&A

The cable is too short to get on top of my desk!

This is the great part; because we used USB connectors, you can just use a cheap USB extension lead to make it longer or shorter as you please. I must stress, however: do not plug this into any USB port, only the plug you made that is inside of your computer case.

Where can I download the code for this?

There is no code.

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43 Discussions

No code = WHEW! Such a great idea. The spring to keep the push off the button is a good idea from below, so it can toggle off / on. I love the LED showing WHERE the heck the button IS! Would this work for laptops - ala remote control, too?

9 replies

If you either: opened up the laptop and rewired the power button, or used a microcontroller with ethernet/wifi capabilities to send a Wake On Lan magic packet to a laptop that supports it.

Would rewiring the power button have anything stick outside of the laptop case?

If I use a microcontroller (eg. Arduino?), would it hook up ala USB? I can't seem to visualize the 2nd option - help?

being that you can turn your computer on with a keypress via a setting in your bios you could build something with an arduino leonardo or an old keyboard

Well, the leonardo is discontinued (seriously? I don't know why they did that) and... That's a wasted USB port.

thankfully they make usb hubs....

leonardo and many other arduino boards got discontinued thanks to the dispute between the two "arduino" companies fighting over the rights

but you can pick up comptible boards on ebay, also you can get a teensy which can also do hid emulation

I have no experience rewiring laptops , but as far as I know yes you would have to have something sticking out as laptops are normally super tightly packed.

Yes, I agree: There would be something sticking out of the laptop, because as far as I know, a big wooden block wouldn't fit in one. Anyways, doesn't a laptop defeat the point of this?

Ha ha! I just love the idea of waking my laptop up with a press of a large wooden block that has an LED light! Plus, it's kind of hard to find the little button to press to turn on the laptop in the dark.

Rewiring: Well, the wires would have to go somewhere. Maybe out a fan port (that would probably be a bad idea). 2nd option: You'd want probably a raspberry pi with wifi (or an arduino Yun) that waits for a button press, then sends a WOL (google/bing/duckduckgo for how to send a "Wake On Lan magic packet from a raspberry pi", it should work for an arduino yun too). See here for laptops with WOL:

Because I'm to lazy to grab my multimeter and check, what voltage is the LED pins on the motherboard? Is it just connected with a transistor to the PSU's 3V3 supply?

6 replies

Thanks for reminding me, I forgot about the resistor. I updated the instructable to have the resistor.

As far as I know it is a 5v output (though I havn't measured it)

I have no idea :P It is designed to be a single LED so i'm guessing you can't pull enough current for an LED strip from it, but maybe if you use transistors you could do something.

By the way: my case has 4 LEDs just for a power indicator, not including the fan lights and the HDD/SSD indicator.

The LED's resistor is already on the motherboard, before the pins you are connecting to... As I understand it, as long as the LED is the same colour and approximate size as the original it should be fine without adding another resistor.

It really doesn't matter if there is a resistor or not: all that a resistor does if lower the voltage. If the voltage is good (3V3-3V7 is usually good) then you can use a standard LED. It also doesn't matter if the size/color are the same: generally a good rule is: uses 40mA or less? It'll work. Also, about a resistor: every PSU has a 3V3 line. There might be a transistor hooked up to a chip that has the 3V3 line hooked up to it.

1) Love it! The recessed LED lighting is beautiful. Great gift idea for older folk... My sister's getting one for Christmas!

2) Thank you for creating a nice, simple project that almost anyone can make. Not all builds need an Arduino...

3) Even thinking about doing this with a laptop is insane. The damn button is right there in front of you, duh! Sure, it's doable... but Why?

4) Because I know how to READ, I will not ask about connecting it to a USB port! ;-) But I will suggest another type of cable: RCA audio cables. Most people already have them. If not, they sell for pennies at your local thrift shop or dollar store. And they too can be extended cheaply. The main advantage is that because the RCA cable is no longer being used much, it is less likely to be plugged into anything else by mistake.

1 reply

I actually don't have any RCA cables, the reason I used USB cables is because they are what I had around when I was making this.

Could I hook up the second switch to my existing switch wires and have both switches work?