Variable Power Supply V2




Introduction: Variable Power Supply V2

About: I've always liked pulling things apart - it's the putting back together again that I have some issues with!

When your building and prototyping circuits , one of the most essential tools you'll need is a variable power adapter. And if you're going to make one you may as well use a Super Nintendo Controller to put it into!

Don't worry, I didn't use a genuine one, it's a cheap knock off that you can buy on eBay for a few bucks. There were a few challengers with ensuring all of the components could fit inside the controller but with a little planning I managed to jam it all inside the controller.

I used an old 3.7v phone battery to run the power supply. These are usually easy to find (just ask around and you're sure to find someone with a few old phones lying around) and small enough to fit inside the controller. You can also easily charge them with a cheap charging module from eBay.

So without further ado - lets get cracking

Step 1: Parts and Tools


1. Super Nintendo Controller - eBay

2. Voltage display - eBay

3. Voltage regulator - eBay

4. 10K pot - eBay

5. 3.7v phone battery - just grab out out of an old phone or you can buy them from eBay

6. Banana plugs: Buy more if you need to make different connections to power your projects

a. Sockets - eBay

b. Inputs - eBay

7. You can also buy these banana plug connectors which will allow you to attach the power supply different ways

alligator clips - eBay, hook clip - eBay, probe - eBay

8. SPDT switch - eBay

9. Charging module - eBay

10. Wire


1. Soldering Iron

2. Pliers

3. Screwdriver

4. wire cutters

5. Dremel (not really necessary but it always comes in handy)

6. Super glue

7. Drill

Step 2: Modding the Case

First step is to open up the case and remove the guts


1. Un-screw and remove the back of the controller

2. Remove the circuit board and cord. You don't need this so you can just keep the wire for another project and throw away the circuit board

3. Remove the D pad and all the other buttons and place somewhere where you won't lose them.

4. Inside the controller are a lot of small plastic pins, gussets, and other plastic parts that you need to remove. You want to make as much room as possible inside the case so trim these off. Make sure though you don't cut the plastic screw holders though

Step 3: Working Out How to Fit Everything Inside

Now that you have a empty controller, you now need to work out how your going to stick everything inside. Make sure you also consider all of the wires that will be needed as well, these can take up a surprisingly lot of room.


1. Place all of the components inside the case

2. Move them around and try and figure out what is the best place for each of them.

3. I decided to put the banana plugs, switch and pot into the 4 button holes which worked really well.

4. Once you have worked out how everything is going to fit, you now need to start to add the components inside the controller

Step 4: Adding the Banana Plugs

The banana plugs allow you to change over connections. For example, you might need power for a bread board so would need jumper leads attached to the male banana plug. Other times you might just want to attach the power supply to the ends of wires soyou'd swap out the banan plugs and use ones with aligator clips attached.


1. As the banana plugs are too long to fit inside the controller, you'll need to slightly modify them. The first thing to do it to remove one of the small, plastic spaces on the banana plug

2. Next, add some super glue to the inside of the button hole on the controller and push the banana plug in. It should fit nice and snug.

3. Add the small washer and solder ring to the small bolt and attach the nut. You'll now notice that the bolt is too long. Use a pair of pliers to trim it flush with the nut

4. Do the exact same for the other one

Step 5: Adding the Switch and Pot

The switch is an on/off switch and the pot is how you change the voltage on the power supply.


1. Place the switch into one of the button holes, add the washer that comes with the switch and fasten with the nut.

2. For the pot, you will need to slightly mod the back of the button hole. With an exacto knife, remove the small, plastic button support completly

3. Place the pot into the hole, add the small washer and fasten with the nut provided.

Step 6: Adding the Power Module


1. First place the module into the contoller and mark where the micro usb will exit the controller

2. With a small drill bit, drill out the area for the female usb head on the module

3. File the hole so it's smooth and remove any excess plastic

4. If the usb fits, add a little superglue to the back of the module and put it into place.

5. Leave to dry for 10 minutes

Step 7: Battery

I found a good source of phone batteries was to raid the recycle box for phones at work. I managed to pick-up 4 batteries last time I checked and they all worked fine.


1. To be able to connect the battery up to the charging module, you’ll need to solder a couple of wires to the battery terminals. First, add a little solder to each of the small terminals on the battery. You should be able to tell positive and negative as they will be indicated on the battery

2. Next, tin a couple of small wires and solder them to the battery

3. You will now be able to connect the battery to the charging module in the next step. Might also be a good idea to check the battery if it a 2nd hand one to make sure it works ok as well.

Step 8: Voltage Display and Gluing the Buttons Into Place

It took me a little while to work out how I was going to incorporate the voltage display on thecontroller. Initially I thought I would just stick it on top of the controller but decided in the end to cut a hole into the controller and have the meter coming out of it.


1. With an exacto knife, carefully mark out the area to remove. I just placed the voltage meter onto the top of the controller and went around with the exacto knife and scored the plastic

2. Next, go over the scoring again a few times to make the cuts deeper. The plastic is thin so you should be able to make the cuts easily.

3. To finish off the cuts I used a Stanley knife and pushed against each of the cuts. The heavier blade went through the plastic and I was able to remove the piece by just going around with the Stanley knife.

4. Use the exacto knife to clean-up the edges of the cut and push into place the voltage meter.

5. Lastly, add a little superglue and glue into place

Step 9: Wiring

Now you have everything in place, it's time do start wiring. I have included a wire diagram as well which should help you understand how the components are connected


1. Solder 3 wires to the pot and then to the power supply module

2. On the out put solder points on the power supply board, solder a wire to each and then solder these to the solder points on the banana plugs

3. Solder a couple of wires to the input solder points on the power supply board and connect these to the battery solder points on the charging module. Make sure the polarities are correct

4. Solder a couple of wires to the battery and solder one to the switch and one to the charging module, making sure the polarity is correct.

5. Add another wire to the switch and connect this to the charging module.

2. Before you totally close the case, test to make sure the power supply works.

3. Carefully close the controller and add all of the screws back into place.

Step 10: Making a Banana Plug Connector

If you want to connect power to a breadboard, then this is how you make a banana plug connector. You can also buy different types of connectors on eBay and I have added a couple of links to these


1. First trim and tin the ends of a piece of red wire and a piece of black wire

2. Place a male banana plug end onto one of the tinned ends and secure into place.

3. Grab a couple of jumper wires for your breadboard and cut one end off

4. Tin the ends and add some heat shrink to each

5. Solder together the jumper wire and the piece of wire and cover the solder point with the heat shrink

That’s it! You are now ready to use your power supply to give your projects some POWER!

Build a Tool Contest

Participated in the
Build a Tool Contest

Be the First to Share


    • Hide It Challenge

      Hide It Challenge
    • Laser Challenge

      Laser Challenge
    • Reclaimed Materials Contest

      Reclaimed Materials Contest



    Question 2 years ago

    Hi, I bought a battery with the exact same dimensions as the one you linked but I am having trouble getting it to fit, do you have any ideas why, it seems to big


    Answer 2 years ago

    You need to probably remove some of the plastic inside the controller. If you are putting the battery into the same place as me then you will need to remove the little round plastic piece in the middle of the "D" pad.


    Reply 2 years ago

    In the end I found an old phone battery that was smaller with the same voltage, I've just finished the build and it turned out amazing. I swapped the voltage display inputs so it now tells me what voltage is outputed, thanks for the excellent tutorial


    2 years ago

    What is the min and max output for this power supply?


    Reply 2 years ago

    around 1.5v to 32v's

    Hey there! Very intresting project and casing however youre wiring diagram instructs people to wire the battery up to the OUTPUT pads of the battery balencer which means none of the battery protection features are in action. I see from the images you posted that you followed this wiring diagram and hooked your battery up to the output pads, I would highly reccommend you go and desolder this as the battery may discharger to under 3 volts causing further issues.


    2 years ago

    That's a funny power supply.
    But you have made an error on your wiring diagram. Battery shall connect to the B+ and B- pads. Otherwise it will not charge correctly. It will not benefit of the over charge and over discharge protection circuit and may harm the battery (and maybe you)


    Reply 2 years ago

    is right and wrong in the same time! :)
    phone batteries have own charging and protection circuit inside, so, if you have a "dead phone battery" you can to pry it off, and get the bare element inside.
    with a bit of luck is ok and chargeable, so, you need to connect it to charger as is shown in module diagram.

    but you can use is as is, with lonesoulsurfer's connections...

    and as a side note, some (old) phone batteries have 3 pins: two plus and one minus.
    one of those pluses goes right to the li-ion element, the other is going through a protection/charging circuit inside.


    Reply 2 years ago

    The diagram is ok - there are actually 2 positive and group out pads on this module so you can connect multiple wires to it. I actually didn't use this one and just grabbed an image from the net. The one I used only had one solder point for ground and positive


    Reply 2 years ago

    Sorry if I insist but the image you grab shows a charging board with a protecting circuit between B- and OUT-. I use this type of board and I know how they work. If you connect the battery on OUT pads instead of B pads you bypass the protection circuit. If someone buy the same board as this one and wire it as you show the battery can be overdischarged and this is harmful for the battery AND the one who is using it.


    Reply 2 years ago

    fair enough. The link in the parts section is for one without the protetion circuit so it will be fine.


    2 years ago

    Also the switch is opening the negative side instead of the positive side. I think a little rewiring is in order. Better to sketch it on paper and examine the charging pcb and then solder the wires.