Building a universal power delivery board for the UNO. Part 1: darlington array

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The UNO has some great advantages for people starting out and playing around, but the 5v/40ma output power limit can be a bit limiting without additional circuitry. While the UNO is not intended to drive anything directly, it kind of defeats the purpose if you have to hunt through and source a bunch of stuff to attach to do anything. As a result, there are a number of boards available. However, I wanted to build a board for the uno that had a lot of power control options, which didn’t seem to exist. The first thing I wanted to put on was a Darlington array.

Relevant portions of the board for the Darlington array shown highlighted.

Relevant portions of the board for the darlington array shown highlighted.

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Liquid Ion work pt. 1 The frame

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I have been doing some work creating CAD models of a friend of mine’s startup product. I haven’t been able to share any of my work before now because it belongs to him, but he has given me the OK now. I am actually really proud of some of the work I did on this. Some of my drafts are not so great, but I had never modeled an existing product and I learned a lot.

600-slide-composite

This exploded view actually didn’t turn out that badly.

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Work Desk PSU Pt1

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Part of my electronics work desk project includes making a power supply setup. I ordered some cheap parts from china to set it up. It puts out 3.3V, 5V, 12V, and a variable voltage.

The green display reads the voltage going into the green plug, or alternatively checks the output voltage of the 3.3, 5, and 12V rails. (More on that in the second part.) The blue display gives the blue (variable) voltage, and  the center display gives you the volts and amps going to/through the two plugs on the left. The two switches control the power supply and accessories, although only on is inserted right now.

Wood is cheap and good for checking fits and sizing.

Wood is cheap and good for checking fits and sizing.

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Fun with GIMP

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I’m a big fan of GIMP and Inkscape. I like the knowledge that they will always be there and that if the need arises, I can modify them. I have been interested in writing scrips, and also in generating textures. Below is an end result of a granite texture I generated using gimp and G’MIC.

I know you can't see it, but this is a really nice render of something that looks like granite.

Why use a camera when you can get a similar result with a computer and a 5 hours of free time!

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Run-away class

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I had tried to make a class to teach how to make basic PCBs. The project was a simple RGB LED and and some resistors to limit the current so that it could be driven directly from the pinouts of an arduino. Unfortunately, I got a bit out of hand in creating material. The part introducing students to LEDs, PWM, measurements of luminescence, and basic V=IR  stuff is mostly complete.

In hopes these documents may be useful to someone else, I have uploaded them here.

Light, LEDs, and Human perception
Questions
There is also a sorely incomplete HTML file here.
Link to datasheet
Legacy WP154A4SUREQBFZGC datasheet V.3 2011-03-02

Christmas cards

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I remember when we got our first printer. Mu sister and I were each going to be allowed to make something in MS paint and print it out. My sister made some sort of underwater scene with a bunch of fishes and a blue water background and printed it out. Once my parents saw how much ink it used they decided that they were not going to let me print out my drawing. Continue reading →