Putting it all together

October 7, 2010 10:44:40 PM CDT

Here's the payoff for several of the last items I've written about: the power header, supplying a breakout board, which in turn feeds power to one of my jellybean oscillators, whose output is being mirrored by one of the 7414 indicator boards.

That much of my basic toolchain has now been tested and shown to work, which is cool. Even cooler is the fact that I have a small handful of breakouts, oscillators, and indicators that I can now use when building other circuits.

Of minor note are the cable bundles that hook the boards together: I've grown fond of using 30 gauge wire for my experimental circuits. My stuff is all low-voltage/low-power, and 30 gauge is rated for 100mA per strand.

Actually, ampacity is based on the resistance of the cable, which is a function of both diameter and length. As short as these guys are, 100mA is probably a conservative limit.

The cables consist of 2-4" chunks of 30 gauge wire run through a 1/2" sleeve of heat-shrink tubing. Usually, the tubing sits about 1/2" from one end of the wires. That gives me a tight end, which is easy to connect to pads that sit close to each other, and a loose end, which can make more widely spaced connections.

I strip 10-15 mil of insulation off the ends of the wires (about the width of a PCB trace.. just enough that you can see the wire), then stob that end into a lump of molten solder. The resulting connection is surprisingly strong, very fast to do and undo, and doesn't have much lasting effect on the solder pad or the wire. Every once in a while I snip off about 20 mil of wire to get a fresh end, but you can do that several times before losing even an inch of cable.

The bundles tend to be easier to work with than individual wires. The first connection acts as a pivot that makes it easier to control the other wires.

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