Archive for March, 2008

Explody Easter Peeps (High Speed Photography)

Sunday, March 23rd, 2008

Explody Easter PeepExplody Easter Peep

(Note: these photos were taken not by me but by my friend David Lindes, who has a ton of other amazing photos on Flickr)

It’s 3 a.m. and a phone rings in the White House…

Or actually, it was about 3 p.m. and a phone rang in my pocket. By luck the phone happened to be mine and on the other end of it was 3ric asking if I’d be able to help with a project that evening. Seems he had acquired about 10 liters of liquid nitrogen and among other things was hoping to use it to do some high-speed flash photography of frozen things shattering into a million pieces upon being shot with a pellet rifle.

All was well and good and according to plan, except for the flash trigger, which was stuck in the mail somewhere. Could I hack one together by evening? Thus is how I got my project for the day.

A flash trigger for high-speed photography is a really simple device. Basically all you need to do is take an audio signal and use that to trigger a flash if the signal exceeds a certain level. Rather than muck about with $10 worth of op-amps, transistors, voltage dividers and a bunch of so-called “electrical engineering”, I splurged for the $2 solution and threw the equivalent of a mid-1980’s personal computer at the problem… i.e. a microcontroller. Specifically, a AVR ATMega168 (mounted on a $30 Arduino).

Long story short and after overcoming two rather significant obstacles (#1 being not having a microphone, #2 being not having a flash) we were able to kludge together a workable flash trigger in just a couple hours. With the flash trigger in place and David at the camera, by the end of the evening we had walked away with some decent shots.

(and made one *hell* of a mess)

(our peep torture from last year)


Serial LED Strip pt3

Tuesday, March 18th, 2008

Here’s a crude mockup of one particular idea I’ve had in mind for the serial LED strips. One particular idea would be to use this as a network traffic visualization.

This was all done in Processing which I have to say, this being the first time I’ve used it, is really pretty awesome. Thanks to Phil for turning me onto it.

Serial LED Strip pt2

Thursday, March 13th, 2008

LED Striplight pt2

It truly astounds me sometimes how much work can go into a PCB layout, even a relatively simple one. I’ve spent a better part of this week refining the design of the serial LED striplights I’ve been working on. I believe they’re just about ready to be sent off to a board house for a prototype run. Infinite thanks to Dan for helping to catch my gotchas before they became design show-stoppers.

Note the bendy circuit traces and teardropped holes. These are apparently things you have to do when you’re designing with flexible circuits in mind.

A Perfect Date

Monday, March 10th, 2008


There’s nothing like spending the evening with your favorite lady sipping homemade vodka infusions and building a capacitor bank to blow stuff up with.

It was totally her idea, too.

Revisiting Old Projects

Sunday, March 2nd, 2008


Today while cleaning up the lab I came across a little blue ball lamp thing which was my first ever LED project some many years ago. I had found the little guy at a garage sale and later swapped out the incandescent light bulb inside of him with a small array of 22 blue super-bright LED’s.

Not really knowing any better at the time, I had wired all 22 LED’s up in parallel with each other, all of them “sharing” one resistor. Ah how naive. No wonder the lamp got progressively dimmer and dimmer over the years as the LED’s fought each other over current, seeing which of them could burn itself out first.

For fun and nostalgia today I decided to revisit my little blue ball lamp and do it proper (or at least more proper). I yanked out the (now half-dead) 22-LED array and replaced it with a 5-watt blue power-LED.