Introduction: Multipurpose Power Supply (with USB)

hey guys this is my first instructable in which i would like to reuse my old computer power supply to make a multipurpose power supply which i can use it in my normal life

Instead of altering or cutting the power supply wires(for connection to the bind posts),i suggest u all to use a 24 pin atx extension wire by cutting the other side of the extension chord apart.this will reduce the maximum delicate soldering part and also will avoid alteriing the smps's wires.

materials rerquired:

ATX Computer Power Supply

20 Pin (or 24 Pin) Female ATX Connector

Plastic Project Housing (here ive made it with sunmica sheets and wooden housing from inside)

Jumper Wires

8 Female Banana connectors/ Bind Posts

USB port female

a toggle switch

an led(blinking or steady)an ic 555 timer circuit can b used for a blinking led as a power indicator

A computer power supply converts the AC power from the wall outlet into smaller DC voltages that power the various components of the computer. They regulate the voltages by rapidly connecting and disconnecting the load circuit (Switched-mode power supply). Most modern computer power supplies follow the ATX convention. They output +3.3V, +5V, +12V and -12V on a series of color coded wires.
Computer power supplies have a number of safety features that help to protect you and the power supply itself. Here are a couple that you need to know about.

Turning on the Power Supply

A power supply is designed to not turn on unless it is connected to a computer motherboard. This is controlled by the green "Power On" wire. Connecting this wire to ground (any black wire) will allow the power supply to tun on.

The connections to the wires are shown in the image shown here.the red wires are all 5v wires,yellow are 12v and the orange are 3.3volts wires.the green wire and any one of the black(ground)wire is to b connected to the two terminals of the soon as green(enable) is grounded,the power supply starts working and current flows through rest of the wires.connect the yellow,red and orange wires to the red bind posts and blacks to the black posts.u can use multiple ground wires for each ground as well.

And here your power supply is ready for any household use ranging from 3volts to 24 volts by connecting two 12v knobs in series.
you can see the video at Handmade power supply:

Step 1: Preparing the Box for Housing All the Parts

here i have prepared the box using sunmica sheets,however v can even use a plastic case to house the entire stuff into it.dont forget to punch in some holes in the box for air to ciculate and the psu to prevent heating.the cooling fan in the psu will do the job of just need to punch some holes into the box that u make.

Step 2: Connections(switch)

cut the 24 pin atx wire into halves and solder the green wire and any one of the black wire to the two terminals of the switch.As discussed earlier,the green wire is the enable wire.This will turn on the power supply as soon as it is grounded.DO NOT TURN ON THE POWER SUPPLY

Step 3: Connections(bind Posts)





BLUE- -12V


solder the positive voltages to the red posts and the gnd voltages to the black posts

Step 4: Connections(USB)

connect the 5v (red) wire to one terminal of usb and the other to can even cut a usb cable and use the female usb to connect it.

Step 5: Final Assembly

fix all the bind posts and switch into the box by drilling holes into it.

(OPTIONAL)Add a blinking LED by connecting it to 3.3v in series with a suitable resistor according to the LED used

assemble the box,here i've masked the corners of whole box with an electric tape to make it strong.Connect the psu to the mains and your multipurpose power supply is ready for use!!!

Step 6: Update(3.5v,5v,12v,+24 Volts Added Using Switch)

using the picture attatcthed,we can connect the blue wire of the psu,(ie the -12v wire) to one terminal of the switch,n the second,i.e the centre terminal of the switch to one of the black knob (first disconnect the gnd wire from the black knob dat u had previously connected),and connect that gnd wire to the third terminal.

as shown in the images above,using this simple step,u can use one same knob to provide two different voltages using a simple two way switch as u can c in the attatched pictures,when the switch is in downward position,the two leftmost knobs provide 12v,and when the switch is pushed upwards,the voltage is raised upto 24 volts.

This is a simple but useful update and also ive added green leds in place of the yellow one by replacing the connections of that yellow bulb circuit.any comments or help is welcome!thank u for viewing my instructable.kindly vote it and like it if u like my instructable!thank u guys!


HeyMister (author)2014-11-01

Could I buy one like this be on eBay? Could I sell one?


it's a home mande power supply..I've made it by myself.I don't think u will get the same one,but u may get other similar smps'es.u wana buy this?or u wana make one n sell?


I'd like to make a sell them, I suppose, I thought you might have had more experience with them


experience ? as in? it works pretty good.sorry but I still didn't understand whether u wana make one or buy one from eBay or other sites?


you may get similar ones,but u won't get one with the same features.try your luck if u get such..

kartik negandhi (author)2014-08-09

guys pl do vote for me in the home technology contest if u like my instructable

fred3655 (author)2014-08-09

How much current is this safely capable of producing? I would like to use fuses with this.

kartik negandhi (author)fred36552014-08-09

As Lynxsys differs from one atx to other..depends on the ratings of each PSU dat u use..

LynxSys (author)fred36552014-08-09

The current that an ATX power supply unit (PSU) can produce is different for each of its different voltage rails. There will also be a maximum total current that the entire unit can produce. Those specifications vary widely between PSUs, which can be rated for anything from less than 150 watts to over 1000 watts. About using fuses: only put fuses on the voltage outputs, never on the ground. I'll refrain from writing a treatise in the comments, but if you want more information, have a look at my guide to hacking ATX PSUs. there are some notes in "step 5" about maximum loads and using fuses.

LynxSys (author)2014-08-09

I really like the 24 volt switch; that's a neat and very convenient way to configure your system. For anyone planning to add the 24 volt functionality: be aware that the -12V rail is only capable of very low amperage (the side panel of the power supply will usually tell you how much), so the 24 volt system as a whole will not be able to provide a lot of current.

kartik negandhi (author)LynxSys2014-08-09

yeah. moreover it saves the space and even cost of two bind posts

Mujaji (author)2014-07-11

This is cool. What do you personally use this for?

kartik negandhi (author)Mujaji2014-07-11

I've made a homemade air cooler which I will b uploading soon..I use it to power dat air cooler and to charge my phone as well..