Scott's Blog

Over the weekend I created a Arduino controlled power outlet based on this design . With this connected to a the Arduino I can control the two plugs independently.  One end (which I cut an old US style plug) I plug into the mains power, the other end I connect to the Arduino (four connections): The fit was a bit tight! I did some tests to see if when the solenoids are on whether is would heat up too much. After about about a 1/2 hour it did heat up to 32 C° which isn't too bad.  So now I'm all set to scare some animals .

I bought the SparkFun LED matrix to go along with the Arduino and here's what I've built. I basically smiles when the build is green and frowns when it's broken. You can find the code at google code . I wanted to have is scroll messages across and there's code to do that, but in the end it was just too annoying since it sits in front of my desk. I have a routine ready, however if I want to give someone a message. To get the text I used wxPython and I draw the text in a buffer, then I look at the pixels one by one and those become the LEDs to turn on. One nice addition is that I can pass Unicode characters and thus it's relatively easy to show special characters like ⚘♂✔✖✈☝ although 8x8 pixels is often not enough and I have to fix them by hand. Another bonus the that program works from the command line so you can print larger messages: ./text2pixels.py --size 30 --bold --font "Delphine" Arduino ### ...

I had some fun this weekend with the sparkfun LED matrix . It's a little bit expensive at $35.00, but looks like it could have a bunch of cool uses. Programming it I had to learn about SPI and I ended up writing my own SPI routines in processing . I've put the code up at led_matrix_tools and some of it is very reusable. Note: I wrote this on October 12th, I just noticed now that I never sent it.

More ideas on what to make: Make a bark stopper, like this one . Make a tennis ball shooter . Make a binary clock .

For years I've been toying with the idea of playing more with electronics, specifically with microcontrollers, to build things like robots. I figure it's the perfect blend of my strengths (programming) with something different for me (electronics). In the past they were pretty expensive and underpowered, but thanks to Moore's Law they can be had for pretty cheap and they can do a lot in one tiny package. I've ordered two Arduino Diecimila USB devices from SparkFun . These things come with the Atmel AVR ATmega168 with 16K RAM and runs at about 1 MIPS which, in comparison, is about the same speed as my first computer, the Atari 1040ST . Each of these cost $35.00 assembled (the chip itself is $5.00) and can be run off of a 9 volt battery. When I looked at these things in the past the most popular ones for hobbyists ran BASIC which I though was stupid and expensive ($125 vs $35). As a programmer I'd much rather program in C or maybe Forth , besides, programm...