brainwagon

Well, it’s done! Here’s my ATtiny13 controlled Christmas LED hat. It consists of an 8 pin, ATtiny13 microcontroller, a pair of 2N3904 transistors and some 1K resistors, a 7805 voltage regulator with two filter caps, and a switch, all mounted on a Radio Shack perfboard inside an Altoids tin. I’m rather pleased with the way […]

This morning I woke up around 5:30AM to catch the lunar eclipse. It was pretty nice: totality began around 6:05AM and the moon became incredibly dark and red. But 30 minute later, it had progressed low enough that it entered the offshore clouds that signaled the arrival of the morning fog. So, I came back, […]

I didn’t have a lot of time to do anything significant tonight, but I wanted to test a few things about this strand of Christmas lights using a multimeter and some simple math. Recap: there are two strands of LEDs, each wired in parallel. One strand consists of 4 red and 4 yellow LEDS. The […]

A few weeks ago I did an experiment that stored an 8 bit PCM file in the flash memory of an Arduino, and then used PWM to flash a laser at a high rate so I could transmit that audio over a long distance to a solar cell based receiver. A few days ago, I […]

I was pondering my laser transmitter the other day, and began to think of how I might transmit digital information from the Arduino to the remote receiver. Since I am old, I remember the old days where programs used to be stored on an obsolete audio storage medium called cassette tape. Indeed, the first storage […]

Fellow hacker Mike Cowlishaw tweeted me a reminder that he had worked on a design for a spelunker’s headlamp that used Luxeon LEDs, and had excellent high performance. I remember that I listened to a talk about this design, but at the time, I wasn’t saavy enough in electronics to grasp the details, and it […]

I’ve been pretty happy with the performance of my linear current based LED transmitter, but that was just sitting on the bench, driving a 20ma device. As I played with the circuit, I began to realize that if I scaled the circuit up to a 1W LED, its deficiencies in terms of efficiency would become […]

My recent experiments with light based communication left me thinking about simple circuits for driving LEDs. I’ve got three big LEDs (1W) on order from deal extreme, so I was looking for circuits to drive these larger LEDs. This Instructable has some good ideas. I’ll probably breadboard some of these soon. High Power LED Driver […]

I always think it is good to follow up a practical build of an electronic circuit with some simulation to try to learn some of the underlying design principles. LTSpice is a great circuit capture/simulation system which runs on Windows, but also runs pretty well under Wine. I was a bit intrigued by the behavior […]

The chaps over at the Batsocks blog sell a cute little gadget called the “Tellymate”: a nice little serial->video converter that is very, very simple. It uses a single Atmel AVR Mega, and handful of other extra components to implement a full character mapped 38×25 character display terminal which reads characters from a serial input […]

Or can you? Courtesy of the Make Blog, here’s an interesting little musical instrument called a “canjo”, a two string banjo that uses an old 4″ tuna fish can as the resonating cavity. Perhaps I should take a break from my plinky string sounds generated with software, and instead do it the old fashioned way. […]

Here’s one for Tom, or anyone else interested in doing ambisonic sound recordings. It mounts four inexpensive Panasonic electret microphones into a tetrahedral array to record sound that can later be processed for surround or other spatialization effects. Seems pretty cool, and they even include the patterns for PCBs that can be cheaply manufactured by […]

I’ve been interested in all kinds of machine tools for a long time, and in the various projects like Rep Rap and the like that use either additive or subtractive technologies. Now that I am involved more in radio stuff, the prospect of milling small pc boards seams very cool, and this little CNC mill […]