Electricity and Electronics

ATX Computer power supply as benchtop power supply. These are quite common around the net, but this is mine with my favorite twist.

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I just discovered these handy voltage regulators while trying to get an LM317 circuit to work.  These regulators are switching type, which means they do not regulate by wasting the excess voltage in a resistive manner as do the LM317 regulators.  Rather, they turn on and off rapidly, and use an inductor to store and release energy for theoretical 100% efficient operation. (more…)

Salvaged and Surplus

I’ve lately realized how many boxes and boxes I have of this stuff.  Probably a hundred or two hundred pounds, not sure.  Old PC motherboards, printed circuit boards, video cards, sockets, wires, capacitors, components galore.  It seems like over the years people have gotten the idea that I collect this stuff, so then they contribute more to it.  Or maybe I shouldn’t blame others.  It’s probably just me… (more…)

This is a followup to the article Breadboarding adapters .  Recently I noticed a post on makezine about somebody that was making plug-in modules for solderless breadboarding, and thought I would share my creations as well.  I also made a battery “juice bridge” a while before I noticed this.  Great ideas. (more…)

ZeptoProg AVR Programmer

Just recently I upgraded my computer, which meant no more parallel port. So I needed a USB method of uploading new firmwares to Atmel AVR mcu’s. (This will also enable me to use my laptop as well for AVR programming.) To this end, I purchased the ZeptoProg AVR Programmer from Mattair Tech, LLC.

It was not without challenges however, one being the permissions under Ubuntu 10.04 for usb devices. Read on for more info about how I solved this using the udev permissions file /etc/udev/user.rules file.

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Some time previous to getting my ham license, I was at a friends house who showed me an LC (inductance) meter built from a kit. It was based on a PIC16C22A, and I certainly do like the PIC mcu’s, but decided I would embark on the task of re-engineering my own that uses an Atmel AVR chip, the Atmega168. It’s been a journey. Also, I am giving away for free, the schematics, firmware, and source code as open source under the GPL. (more…)

Desoldering Tweezers

Here is a new desoldering tweezer tool I just made, it’s rough and there will be improvements, very likely.  It looks kind of dangerous, but it’s really low voltage, under a volt, barely enough to register on my digital voltmeter.These tools cost hundreds of dollars if you want to buy them somewhere, but I made mine out of cheap radio shack parts and junk.  The power supply is also homebuilt, which I also use for my hot air pencil .  (more…)

Recycling old ISA cards

I’ve long been a fan of solderless breadboarding.  And frankly any kind of breadboarding, even the soldering type.  When you need to whip out a circuit fast, don’t have time to etch a board, here are some of my tricks.

Hot wire cutting bow, top terminal

Here are more details on my hot wire foam cutting table.  I show the details of the terminals attaching the hot wire at top and bottom.  The bow is made of threaded rod so adjusting an angle on the wire is trivial. (more…)

Here is a jacob’s ladder I made, and I added a little circuitry to make
it act as a speaker.  Then, of course, the best thing to do next was
play the song “We Are Climbing Jacob’s Ladder” through it.  The sound
is a bit quiet in the background, but it’s there, and it’s all produced
by the arc.  Enjoy. (more…)