Making A Project Box Fun & Interesting
This article covers how I built a simple project box from aluminum and wood to house the components of a power supply for my workshop video camera.
To make videos in my shop, I have a camera setup that I’ve been using for more than a year that basically stays out there attached to my camera gantry. The camera runs on a small battery that typically lasts for just an hour or so of shooting before I have to replace it with a freshly charged one. And while this is not usually a problem, since most of the projects are quite short, it can be for the bigger ones.
I thought a good solution would be to build a simple power supply that runs off of the cordless tool batteries I have mounted on the gantry to run this LED light. The tool batteries put out around 19VDC, and the camera battery puts out around 8VDC, so I’d need a simple way to drop that voltage. I have a few components on hand, and among those is an adjustable voltage regulator – LM317. Here it is with the camera battery and the resistors I used to select the voltage:
I used an online calculator to determine the values for the resistors to get an output as close to 8VDC as possible. That worked out to be 220 ohms for R1 and 1200 ohms for R2
Here it is wired up “dead bug” style (doing it without a circuit board):
Pin 3 is the output and pin 2 is the input on this particular device. If making something like this yourself, always confirm the correct pinout on the brand you have, since it can vary sometimes.
Next, I ran into a bit of a setback. My original idea was to use an old battery that still works, but only last for a few minutes, as the dummy battery to plug into the camera. I took the shell apart and found this inside:
At this point I’m thinking that I should try to work with this circuit board, since there are 3 pins coming out of the battery. And even though the supply voltage shows on the outer two, the middle one may be doing something:
But I decided to ignore that hunch and strip the terminal off of the board so that I could wire directly to it:
Glued the battery shell back together with epoxy and wrapped tape around it until it dried:
And on plugging it it powered, I get this:
Should have followed that hunch! Lesson learned and a slight delay to wait for a proper dummy battery to come ($14.99).
When it came, I got start on making the box that holds the regulator components. Since the regular is dropping 11VDC at a fairly high current, it needs a heat sink to keep it from burning out. I came up with a simple box design that uses aluminum for the front and back panels, and hardwood for the ends and sides.
I started by cutting out two strips of maple. One 1/8″ thick and the other 3/8″, both from a 3/4″ board:
The box I want is small, just 2″ x 4″, but this method can be used for any size by making the parts bigger.
The ends are cut from the thicker strip and I took the time to “hollow” them out in the middle, while leaving enough space for screws at the ends:
Sometimes you need to put a jack or switch in the end and the material needs to be thinner for that.
I glued the frame together using 5 minute epoxy, and wrapped masking tape around it to clamp the parts together:
The front and back were made from a scrap of 1/8″ thick aluminum:
I sanded it with the random orbit sander to clean it up and give it a matte frosted finish.
After cutting out the top and bottom to rough size, I glued the bottom to the wood frame with epoxy:
For a bigger box with a thicker frame, screws can be used instead of epoxy for the bottom.
I started in on filing the bottom flush with the sides and ends and was filming that for the build video, when the battery went dead in my camera, neatly illustrating the problem I’m trying to solve with this:
the top panel is fastened with screws and here I’ve clamped it in place to drill the pilot holes:
I could then enlarge the holes in the lid and countersink them for the #4 screws that will hold it on:
Original plans was to just clear coat the wood and frosted aluminum, but the result was too low contrast and I didn’t think it looked attractive enough to pull in viewers, so I painted the top and bottom covers blue:
Another option would have been to use a darker wood, like walnut, to get the right contrast. But of course all of this is only an issue if you are making this in a video, and need to attract easily distracted viewers.
With the box done, I can get the parts put inside. In addition to the regulator, I found a 2.7 ohm power resistor that will absorb some of the current (heat) before it gets to the regulator, and that’ll keep it running a bit cooler:
Also a switch to turn it off and on makes sense, even though the camera doesn’t draw any current when it’s off.
A critical part of doing this is to stop and check and double check that everything is actually working correctly before plugging it into a $1500 camera. It doesn’t take much of a mistake to be a big setback:
Confirming that the rig will power the camera before buttoning everything up:
The power is taken from the terminals on one battery, and I wired directly to that:
The switch installed in the side panel and the box itself screwed to the gantry:
Otput from the regulator wirde directly to the lead on the dummy battery. Heat shrink is so handy:
All done and ready to use:
At this point I’ve used the camera several times with this supply, even leaving it on for extended periods (10+ minutes) without any issues. The top panel of the box is the heatsink for the regulator and that does get warm to the touch, but nowhere near hot enough to cause concern. Still, if you decide to do something like this yourself, it would be wise to always keep an eye on things to make sure it doesn’t overheat.
The battery door on my camera has a notch for the power cord to come out from the dummy battery:
Here’s a video showing how I made the box: