Tuesday, November 3, 2009

LED Tester Mark II

Ok, so the last one I made had a serious flaw... it'd burn out any LED that couldn't take 3V... Oops! I recently bought a new soldering iron (variable temp, xytronics from allelectronics.com) and wanted to play with it, so I thought it was time to replace the LED burner with an LED tester.

Basic ingredients: wire, some resistors, an 8 pin DIP socket, a pushbutton and some perfboard. I treated myself to an automatic wire stripper the other day ($8 from Fry's), it's great! I've been using it quite a lot. No need for it in this project really, but I like to show off my toys.
Here's the basic wiring and soldering for the resistors and socket (this is what I messed up in the first iteration):

At midnight I ended up with the following "finished" product (I should have learned by now not to start late at night...):

The problem was that I'd completely wired the push button wrong. In the above wiring, the power lines are connected to the positive and negative rails on the DIP socket, which meant the LEDs lit up as soon as they came in contact with the DIP. On pushing the switch the LEDs would turn off because the positive and negative leads from the battery holder were shorted... bah!

A few days later, I came back and repaired it (button connects and disconnects +ve terminal, -ve terminal is wired directly):

A view from the top.

Single LED test. You can see the multi-LED test picture at the top of this post.

The soldering iron is much better than the Weller I'd bought (it was a bottom of the line weller min you). It heats up fast and the tip is noticeably better quality. The power cord, however, is very thick and reduced the maneuverability of the iron.

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