No, I said I need some “juice”

One of the things I’ve noticed about electronic devices is that they all, unequivocally, run on electricity.  Microcontrollers and small motors and actuators and sensors and such are also fairly picky regarding the voltages they’re interested in using.  Primarily, microcontrollers require either 5V or 3.3V of power with very little tolerance away from their ideal supply.  The flow thus needs to be very regulated.

To do this efficiently a specialized power supply is often required.  Hobbyists with too much money at their disposal opt for bench supplies that have perfect little power nubs at different voltages and lots of fancy meters.

I don’t have too much money so I decided to see what I could do to make my own:

You’ll note that by checking out the back of it, it’s actually just an ATX power supply I’ve re-purposed from an old PC.  The wooden carriage for it is a few slabs cut from a desk that has long ago been retired.  One of those ones that you have to put together yourself alone in the dark of your apartment while you wonder about what might have been as you scrawl through useless misdirections and absent hardware.  The stain for the wood is called “Anything But Particle Board” and doesn’t match at all with the PCB mill I’m working on that’s positioned next to it.  The front piece isn’t attached yet, so the wiring is a little exposed at the moment.  Makes for a better picture/story.

The top of it has a power switch, a voltage supply indicator light, which is illuminated when the supply is able to maintain all regulated voltages given the current power draw on it.  It’s basically an “all is well” light.  Above that is a reset button, and to the left are 4 terminals, for 3.3V, 5V, 12V and ground.

A nice aspect of ATX supplies is that they are wired with a non-mechanical on/off feature that allows you to turn it on by sinking the power on one of it’s pins.  It also has a constant standby 5V output.  By grounding the power pin the supply is turned on with the switch I’ve installed.  By shorting that with the standby output, the reset button allows it to power down and restart.

Another bonus feature of the ATX supply is that it will cut off its voltage if it detects a short circuit or an unsafe draw of power.  This means that it will shut down as soon as it detects itself firing watt upon watt of electricity through your overweight, out of shape shell of forgotten dreams so that you can live another day to ponder the decisions in your life that led to this point.

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