My New Power Supply

This is a project that’s been in the back of my mind for a long time but I just never seemed to find the time to build it.  When I saw the new ATX Breakout Board by Dangerous Prototypes, I was inspired to get the project started. 

This build is for my home office which I plan to eventually be completely decorated in fine hardwood (built by yours truly).  So, I wanted this piece to be a blending of fine furniture and high tech.  With that goal in mind, I got to work.

The dimensions of the box were based on the dimensions of my Rigol DS1052E oscilloscope which will sit on top of it for now.  It’s a little deeper due to the requirements of the ATX power supply that sits inside.  If my lumber had been a little wider, I would have liked for the box to been maybe an inch deep than it is.  I didn’t end up with as much clearance as I would have liked inside the box.

The casing is made from a single piece of scrap walnut and the grain is maintained around the perimeter of the box.  The top and sides are joined with a miter joint and the bottom fits on with a large box joint and is screwed on.

 

<-- No, that is not OSHA approved footwear.

 

Then I used a 1/4” straight bit on my router table to cut 3/8” deep dados for the front and back panels to fit into.

Note that after a test fit, I later realized that the dados needed to be extended all the way through the feet of the box so that the front & back panels could be removed after everything was glued up.  One of my design goals was to make it so that I could easily remove & modify the front and back panels later if I come up with other things I want to add.  This list has started already….

After cutting the front & back panel blanks out of 1/4” hardboard, it was time for a test fit.  The bottom was sanded a bit to make it easy to put on & off then it was time to start the glue up.  I used a tape clamp method to glue up the miter joints.  To do this, you just fit the top & sides together tightly while laying on a flat table and then put some 2” masking tape the full length of the joint. 

 

Flip the parts over and glue thoroughly and spread with a glue brush so that both sides of the joint are fairly heavy in glue.  It’s better to have too much glue than too little since the squeeze out will help fill in any cracks you may have in your joint.

 

 

Since the box bottom is held on with screws and is not glued, I was able to take advantage of this and use the screws to hold the box together while the glue dried.

I gave the box 24 hours to dry before doing anything else with it.  In the meantime, I started work on the front panel. 

 

The ATX Breakout Board breaks out +12V, +5V, 3V3, –5V, and –12V.  I had some premium screw down banana plug studs that I had bought for this project months earlier.  The breakout board comes with some cheap banana plugs.  So, they went into my parts bin. 

I laid out the parts on the front panel and drilled all the holes for the banana plugs, LEDs, main switch, and the breakout board.  I wanted everything mounted on the front panel so that if I wanted to make any adjustments, I would only have to unplug the power supply and slide out the front panel without worrying with parts attached to the case in other places.

The ATX Breakout Board comes with a push button switch soldered on.  This wasn’t going to be of any use to me since I planned an external toggle switch.  Unfortunately, the switch that came on the board was going to be in the way of my power supply.  So, it had to be removed.  This wasn’t a simple task.  In the end, I decided that destroying the switch was going to be the easiest and most time efficient solution.  I would recommend to Dangerous Prototypes that they leave this switch unsoldered.  It’s a lot easier to solder the switch on than it is to remove.

Once the glue was good and dry, I put a large roundover bit in my router table and rounded over all the outside edges of the box and sanded it down to 400 grit and finished the walnut with a first coat of Danish Oil and then a couple coats of rub on polyurethane.

The power supply is mounted to the top of the box with an angle bracket and screws.  A piece of wood was glued to the bottom inside of the box that is equal in height to the spacing between the power supply and the bottom as a way to hold up the front side of the power supply.  The back side is held up by the back panel.

Note the air holes drilled in the bottom at the front of the power supply.

The power supply has a built-in blue LED glow :)

The green LED in the top left corner is the mains power indicator.

 

 

 

The plugs aren’t labeled yet.  I’m still searching for a more elegant way to do that than just sticking on labels.  I may actually end up having a piece of 1/4” plywood laser cut & etched at some place like Ponoko to make a new front panel.  The empty area to the left of the plugs is dying to have a logo or something etched on it!

This has been a fun project and I especially like the blending of woodworking & technology.  These are the types of projects I had in mind when I started “Software & Sawdust”.  I plan to do a lot more like it in the future.  Stay tuned!

EDIT:  As many have pointed out and I failed to mention in the original post, the DP ATX Breakout Board has 1.25 amp polyfuses which seriously limits the power supply in it’s current state.  I’m in the process of sourcing replacements for those polyfuses that will allow better utilization of the full capacity of the ATX power supply.

7/18/2012 – Woo! Hoo! The folks over at Dangerous Prototypes blogged about this project.

7/20/2012 – Woo! Hoo! Hoo!  It made Hack A Day!