Synoptic Labs

My prototype boards for the striplight came in this week, woohoo! Now starts the process of putting the design through its paces and making sure it works but before that can begin the boards have to be first assembled.

According to the guys over at SparkFun there’s no better way to do bulk surface-mount soldering in the home than with skillet reflow. According to universal truth, there’s no better use for a skillet than for making delicious fluffy pancakes. Thus it follows that any activity combining the two must be a doubleplus good.

Besides, heavy metals poisoning is the sweetest sauce.

(more…)

Rob and I have recently been talking about doing some wireless projects. A friend loaned us a Cypress CYM6935 module which is an evaluation module for the CYWUSB6935 chip and today we attempted to hook it up. We chose an Arduino board simply for convenience though connecting the module to it actually took the bulk of our time today since the 2mm pitch pin headers on the module won’t fit into a breadboard. Also, the Arduino runs at 5V and the Cypress chip can’t tolerate voltages that high so we had to drop the 5V signals from the Arduino down to 3.3V. Fortunately I had a Futurlec 5V to 3.3V level shifter board on hand so that problem was easily solved.

Once we got the module wired into the Arduino we had to figure out how to communicate with it. Thankfully, that work has largely been done already and we borrowed code written by Lars Englund (available here) to test the communications with the chip. This code was written for an ATMega8 so a few of the port definitions needed to be changed to make it run on the Arduino’s ATMega168, but this was fairly painless.

It should be noted to avoid possible confusion that, while we used the Arduino board, we did not use the Arduino programming environment to compile and run Lars’s code. His code is not compatible with the Arduino framework and would require significant porting. (this is not a criticism of the code but rather a disclaimer intended for those who may find this post. It’s not commonly understood that the Arduino hardware is perfectly happy functioning without its development environment).

Anyways, once we got the code to compile and talk back to us via the USART and once we got the Cypress module wired up to the board, we were pretty much done. Much to our surprise the software found the chip and was able to talk to it on the first try. Honestly, we had expected to be chasing stupid wiring mistakes for another few hours so this was a pleasant shock.

That’s pretty much where we left it. We got the software to recognize the chip and talk to it and we called it a productive day. Now what’s left to do is get it to scan the wireless spectrum and send that data back to the host computer for analysis and display.

(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)

(more…)

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.

(more…)

A week or so ago I picked up a modest quantity of Wood’s Metal, a low melting-point alloy which melts around 158 degrees F. I’ve been playing with the idea of using it as a dynamic circuit element in a display of some sort.

On saturday I built a LED array with pins that extended through the bottom of the circuit board as a proof of concept. The idea being that the LED’s would all be wired up with their cathodes tied to ground above the board and their anodes extending as naked pins beneath the board. Power would also be wired as separate naked pins beneath the board. Liquid metal could then be flowed underneath the board, randomly connecting and disconnecting the LED’s from power, turning them on and off as the metal flows by.

(more…)

My friend Rob’s birthday was coming up and a few of us got together to throw him a surprise party. Since Rob has been running a with a streak of high-voltage projects these past few months, what could be more appropriate than incorporating some extra volts into the surprise?

Solution: a high-voltage themed birthday cake with little Jacob’s ladders for candles.

A picture of the candle assembly before installation. The picture doesn’t show the arcs very well as they were a fair bit bigger than this picture suggests:

(more…)