brainwagon

Lee mentioned that the there was a way to change the analog reference used on the analog inputs to the Atmel AVR to an internally generated 1.1V, which would give me a lot greater resolution (about little over 1mV per step). Indeed, a little quick searching yielded that it was not only true, but dead […]

I had an application where I wanted to detect temperature. No big deal, lots of good temperature sensors exist. But of course, I don’t have any of those. Rather than order something from sparkfun, I thought I’d just try to see what I could do with the stuff I had on hand. What I had […]

I keep looking for cool projects where people build small computer and microcontrollers, more or less from scratch. Today, I ran across FIGnition: FIGnition is a £20 educational DIY computer which works like an 8-bit home Micro: outputting to composite video and ready to be interactively programmed from the moment you switch it on. It […]

I mentioned that Roger, G3XBM was shifting from the very low frequencies to much higher frequencies. His interest has already uncovered some links that I hadn’t seen before. One very cool thing was his discovery of a local 477Thz beacon (that’s red light) that is aimed roughly in his direction at a distance of around […]

A conversation I had recently got me on the topic of solar energy, and introduced me to something I hadn’t heard of before: maximum power point tracking. The basic idea is solar cells exhibit a complex non-linear relationship between illumination, temperature and resistance. This is usually represented by an curve that (for a given temperature […]

I’ve mentioned Codec 2 a few times in the past, but for those who don’t rememember, David Rowe has been working on a very low bitrate codec optimized for speech applications. This is of interest in amateur radio because we don’t have a suitable speech codec which isn’t patent encumbered (if for instance, DSTAR’s AMBE […]

Courtesy of Phil Harvey’s Puzzle « Programming Praxis, I discovered that the numbers from 1..16 can be partitioned into two 8 element sets, with these nifty identities! 2+3+5+8+9+12+14+15 == 1+4+6+7+10+11+13+16 22+32+52+82+92+122+142+152 == 12+42+62+72+102+112+132+162 23+33+53+83+93+123+143+153 == 13+43+63+73+103+113+133+163 There has to be a good way to use this to make a cool geometric puzzle as well.\ Bonus: […]

I’ve stopped hacking on my Arduino/Gameduino satellite tracker for now. Here’s the final video demonstrating it running: I’m currently working on the final schematic which will be posted on this permanent page. The code will be available github.com, for right now, it includes the library that I wrote that does the satellite prediction. I’ll be […]

I’ve been playing a great deal with Arduinos lately, and have acquired a couple of Xbees to experiment with wireless. But Xbees, cool as they are, are kind of expensive for many tasks where a much simple RF link could suffice. Today, I ran across the JeeNode, which is available as a kit from Modern […]

I like operating systems. My first exposure to Unix was a revelation. Unix was a complex operating system that provided useful facilities for programmers, and it wasn’t written in assembler and locked away: it was written in C (the same language that you use to write ordinary programs for Unix) and it was understandable. This […]

I was looking for beacon circuits, and ran across VK3YE’s USB powered 40m transmitter. Unlike most simple beacon transmitters, this one transmits double sideband, which makes voice transmission possible. I like the basic idea! USB port powered 40 metre milliwatt transmitter on air – YouTube Very cool. He’s also got an awesome awesome YouTube channel, […]

Legendary QRP hacker Steve “Melt Solder” Weber has some awesome stuff on his website, particularly if you are interested in homebrew ham radio gear.   (Indeed, it appears he’s about ready to offer his legendary ATS-4 5 band rig kits again, experienced kit builders might want to check it out.)   But what drove me to his […]

My tinkering with my ATtiny13 based pumpkin circuit had me thinking that perhaps I should try to make something similar, but solar powered. Luckily, Windell had already anticipated my needs, and had put up a nice simple page with some circuits to experiment with. If you want a simple solar battery charger, or a simple […]

I got one of these boards the other day for free: STM32L-DISCOVERY – STMicroelectronics. Even if you didn’t get one for free, they seem to be pretty cheap: Nu Horizons has ’em for around $15, Mouser has them for $11.67, which makes them pretty much cheaper than every Arduino you can order. But what do […]

Like nearly everyone in the Bay Area, I spend too much time in my car, and one of the ways that I endure it is by listening to a lot of podcasts. Most of these are technical in nature, and in particular, I’ve sampled most of the ham radio podcasts out there. One of the […]