paul's Blog

Standalone (Txtzyme) Sparkles

Submitted by paul on Sun, 2011-07-10 17:27

At the Open Source Bridge hacker lounge, Ward Cunningham was talking about borrowing a Mac Mini to run his Txtzyme Sparkles at an art show.

Rather than go home at a reasonable hour, I thought it'd be fun to try implementing all the math directly on the Teensy++, using only the Arduino IDE. Making it run was easy, but doing the math as fast as the computer+USB was quite a challenge.

"Read more" for the stand alone Arduino-based code.... which can run as fast, even faster than the USB communication allows.

Hand-Eye Supply's Starlight Parade Float Wins Award :-)

Submitted by paul on Mon, 2011-06-06 17:38

I recently got involved in helping with the electronics+software for Hand-Eye Supply's Starlight Parade float, designed by Laurence Sarrazin. It won the Parade's "Sweepstakes Award - Best Illumination"!!! Here's more news coverage and Core77's announcement, detailed announcement and Behind-The-Scenes build story (with time lapse video).

The lighting wasn't very bright, but there were 114 computer controlled circuits. It was really the only float in the whole parade where the lights "did something" (Robin's description). Indeed they blinked and faded in lots of complex patterns.

"Read more" for technical details and source code behind this float's lighting, and the crazy story of its construction....

Sparkfun El Sequencer Trouble...

Submitted by paul on Mon, 2011-05-23 05:33

Update, July 14, 2011: Sparkfun contacted me... they're planning to fix these problems.

Over the last week, Mykle and I have been helping the Hand-Eye Supply folks with a float for the upcoming Starlight Parade. It has 114 El Wires from Coolneon! We're using the only off-the-shelf el wire sequencer available, made by Sparkfun (a new 10 channel board has recently been announced by Coolneon... and perhaps if you're reading this after 2011, maybe I'll make a better one someday).

Sadly, the Sparkfun El Wire Sequencer board has been nothing but trouble. Mykle insisted I write up a list of all the problems, so anyone else struggling to use these boards might find this info. Click "read more" for the ugly details...

Peak holder

Submitted by paul on Mon, 2010-12-06 15:17

A simple peak holder circuit, for interfacing piezoelectric transducers to AVR analog inputs. (thanks to Laen's PCB group order!)

The analog circuit amplifies the signal (gain of 2), and the output capacitor holds it. The AVR should discharge the cap after reading a peak, by momentarily turning the pin to digital output.

Light Table

Submitted by paul on Sat, 2010-06-19 13:09

In my slow but steady quest for better macro photography of electronic projects, I decided to build a light table to (hopefully) eliminate shadows.

With boards from Laen's PCB group order, materials from TAP Plastics, 15 white LEDs and misc parts I mostly had laying around, this is how it turned out:

Read on for electronic details....

Accel-only breakout board (working)

Submitted by paul on Sun, 2010-06-13 11:10

Boards from Laen's PCB group order arrived today, and I'm happy to say the Accel-only breakout board works. This was inspired by Sott's design, but with support for 5 volts, and using I2C.

I'll have 4 more kits at the next Monday meetup. The kit has all parts except the MMA7455 chip, and the kit's FREE if you build it or wreck it trying. So far, I've only written a tiny test program. Here's the code:

Accel-only breakout board

Submitted by paul on Fri, 2010-06-11 16:52

At the last meetup, I handed out 4 kits for an accelerometer-only breakout board... sans the bare PCB since they're delayed. Anyway, here's the parts placement diagram:

On the next group order, I'm going to send in an Accel+Gyro breakout board. Thanks to Scott for finding these cool chips!