Hi in this instructable I will show you how to make your own variable power supply, which is capable of delivering up to 5A at 12V.

Step 1: Parts

For this project, you will need mostly parts from eBay and local hardware shop. You will also need some basic tools like soldering iron, knife, solder, screwdriver. I put international purchase links below:

step-down
step-up
step-down 5A
potentiometer
screw terminal
male dc plugs
display
banana plug
ON OFF switch
power supply
Circuit board

Step 2: Getting All Together

Get all necessary components together and testing them out first to see if they are working correctly.

Step 3: Testing the Display and Modules

So I powered my display as shown on wiring diagram then I connected 12V motor to the terminals and started rotating potentiometer to see if display functions correctly. Next up was the step-down module and lastly step-up.

Step 4: Power Distribution

This step is optional but it will make your life a whole lot easier when you assemble power supply. Start with laying down some terminals and solder one-half of terminals to common GND and 12V.

Step 5: Housing

I designed case in cad software Fusion360. You can download stl file.

Step 6: Assembly

First I inserted all potentiometers and banana plugs that I saw how everything fits together. Next up I desoldered all trimer potentiometers and soldered some UTP wires from old internet cable and soldered ends to potentiometers, I added some 0.75mm wire to ends of banana plugs and put them on ends of regulation modules.

Step 7: ON/OFF Switch

Cut some wire and solder to the switch before power distribution and parallel to LED.

Step 8: First Test

Here are some of the voltages.

Step 9: Indicator LED

This step is optional but is really cool to have some indicating light, color does not matter I even used a bicolor diode and trimmed one leg away. First I checked operating voltage of the diode (which was 3,3 V) and then added 2k ohm resistor in serial. And it worked fine and it looks awesome.

Step 10: Creating Plugs

I made two pairs of plugs one for the perfboard and one with alligator clips. If you want to make some too just follow pictures. I used some fine needle so I can stick inside some female plugs of arduino.

Step 11: Conclusoin

This project was really fun and educating for me. I had some problems with 3D print but at the and everything turned out great. I even have to heat one side of the enclosure to fit all together.