May 2011 Archives

Dead bug construction

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So I thought I was pretty proud of myself for building a PIC based stepper driver. There was a small defect in the final board layout that required me to solder a couple resistors to the back side instead of through the top like all the rest of the components, however, in testing the board with a 555 based step generator, it worked!

That is, until I tried using the signals from the parallel port. Since electrical engineering is not my profession, I'm not 100% sure why the signals didn't work, but my guess is the 3V from the parallel port was not strong enough for the PIC to register the logic Highs. So I had to some transistors to convert the 3V inputs to 5V for the PIC.

The problem was the boards were already etched and soldered. Building new boards from scratch when I only needed the 2 boards I had started did not excite me. So I utilized a tried and true method of "Dead Bug Construction" to add the 4 resistors and 2 transistors to each board. The results, while not pretty, do work.

Dead bug PIC driver

Jetman coming to America! - Scratch that.

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As reported on CBC's website, Yves Rossy is planning to fly his jet powered backpack style wing over the Grand Canyon. That will make for some great photos, videos, etc. Here's wishing him good luck!

Update (an hour later): While the FAA gave him permission, Yves decided the time frame was too tight and canceled the flight, and he was not comfortable he would have time to train / practice flying in such a "challenging" space. Too bad. Looking forward to the next flight!

CNC - Parallel port breakout board - with Lights!

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I need a clean way to break out the pins from the parallel port to the various stepper drivers, etc. I had a rats nest on a breadboard for a long time, and for almost as long of a time, I had an Eagle file that would make a nice breakout board with status lights. The plan was to mill the PCB board, but I have been having too much fun laser printing the negatives onto magazine paper, ironing them onto PCB. Anyhow, for those who are interested, this is what the board looks like:

Parallel port breakout board

The LEDS are in 3 groups of 4 pins, they pass through the header to the LED / resister for status. Beside the big connector is 4 input pins for home signals, etc.

Parallel port breakout board - backside

This is the back side.

And for those interested, here is the LED_SIGNAL_V2.brd.