$2 DIY bench power supply for testing emitter and powering a hobby charger.

I recently received my Imax B8+ charger and have been trying to get a 12v power supply ready for it. Since I could also use a decent bench supply for other voltages I figured I'd go the usual route (cheapest) and make my own. I finally got the last of the needed parts yesterday so I began the assembly. All that is left to do is complete the internal wiring and that will happen tonight.

I am using an old computer power supply (psu) for the internals. This will provide me with 12v, 7v, 5v and 3v supply. I found a cigar box the perfect size to just fit the psu along with some external fan grills I had in the basement, a master switch ($1), and a speaker connector panel I picked up at Radio Shack on clearance for $0.87). Total investment? $2

Here it is so far:

On the inside it looks like this. Just remember that the wiring is not completed and will be greatly cleaned up inside:

Pretty darned wesome what $2 can still buy these days!



That is Sweet! I wouldn't mind building one myself. Did you follow any particular "DIY Guide" to build it, or just do it? (ie. do you have any links for the procedure?)


How many amps you think if coming out of the 12v rail? I’ve got a bunch of old power supplies, this would be handy since I’ve already managed to fry a led by “testing” different batteries.

Here you go, Garry!

Nice build! I have an ATX supply I hacked into a bench supply, although I put the banana jacks ad master switch right into the metal case of the PSU.

One thing to note: these power supplies are not current-limited the way a proper lab supply often is. You can easily short many amps through something if you are not careful. Easy to let the magic smoke out.

Oh, and excellent cigar selection as well!

awesome job, love it. 8)

Here is what they claim for an average 300W supply:

Thanks for the information! I have numerous atx supplies in the garage that I couldn’t part with! Now look what i can make. The woman will be so happy that i have another BLF inspired project. Lol


Nice job Johnny!

I have never seen a power supply enclosed in Spanish Cedar. Very creative!

Thanks, guys! Yeah, even my step-son came home last night with his girlfriend and saw it on the kitchen table. He came into the living room where I was and asked, "did you make a power supply inside a cigar box?". I replied, "yeah, man" to which he said, "that's awesome!" :bigsmile:

Very nice project JM Kudos :bigsmile:

Thanks for the link! I actually started Googling and found that link in addition to this one: http://www.instructables.com/id/Convert-an-ATX-Power-Supply-Into-a-Regular-DC-Powe/#intro


AT PSU’s are even easier to convert.

If you happen to have them lying around. I think I have about 50 of them so anyone within 3 hours drive of me can have one for free. It’ll help clearing the crap from my house.

Issue of the Resistor

Power supplies need a certain minimum load to work properly. The min. load for mine is around 0.8 amps. Thus if you plan on powering LED’s or other such low-power device exclusively, you’ll need a resistor to provide a load. Otherwise you will damage the PSU.

A meaty 10-Ohm, 10 watt resistor from Radio Shack is a good choice. Wire it across 12 volt and ground.

One of those articles also suggested wiring it so that the cooling fan became the load.


Excellent idea!

interesting! I wonder if one of these could be used to do home anodising? Most guides I read specify a certain amount of current per surface area, whereas these are voltage controlled instead. It certainly would make it a whole lot cheaper if it would work.

Current for anodising is best at lots of amps. Preferably more than your typical PC PSU can provide. The more amps the better (generally).