Nuts and Volts - November 2011

control cogs: 1) runs a menu-selected mini light show; and 2) when active, sends a message via Morse code using one of the LEDs. Have a look. I think that once you see how simple it is, you'll be very excited about doing big things with small LEDs.

PDBS IN A HURRY

The display that went to PAX was actually the second of two. Having been through one grueling build where I hand-wired hundreds of LEDs, I helped myself the second time by using PCBs instead of perfboard (which I could do now, knowing the size of each LED panel). The problem was cost; sending out for prototype PCBs would have been really expensive, and we had already set a budget for materials.

My good friend Peter suggested that I have a look at a product called PCB Fab-In-A-Box from Pulsar Pro FX — and man, am I glad I did. With this system, you can output your PCB design using a laser printer onto special paper that comes in the kit. The toner on the paper is transferred to the PCB (also in the kit) using a modified laminating machine. The laminator ensures proper heating and pressure to do a good transfer — something that's tough to get right with an iron.

There is another step before etching which is what allows this system to create such high quality boards: The board is run through a second time, this time with a green sealer. Toner is somewhat porous, so the sealer fills any pores which is what allows the system to create high quality traces, even when the line pitch is very fine.

Etching is handled as with any other home-etched PCB, and toner removal is easy with a bit of acetone. It took a bit of time to cut and drill the boards, but this was less time and far less expense than waiting on prototype PCBs from a traditional board house. Figure 5 shows one of my spare PCBs. After rough cutting the boards from the 8" x 10" master PCB, the shapes were refined and holes drilled using a Dremel tool. Finally, the boards were chemically tinned to prevent oxidation prior to soldering on the resistors, LEDs, and wires.

The other great aspect of this system is customer service. I didn't have time to make errors, so I was quick to pick up the phone and call company owner, Frank Miller, for guidance. He was fantastic. At every turn, he was there with good advice and support. I'm looking forward to trying his labeling product which uses similar processes and — he told me over the phone — he's working on a flexible PCB material that works with his system. For the kinds of things I do around the film industry — especially with costumes — building flexible PCBs at home will be fantastic.

Have a look at PCB Fab-In-A-Box — it can be a lifesaver. The great thing is I can now build PCBs over a weekend, especially for my quick-turn, small scale, and one-off projects.

Happy Holidays!

You know what? This is my final column for the year,

SPIN ZONE

■ FIGURE 5.

so let me bid you and yours the very best for the season and the coming new year. As ever, I am appreciative for my friends at Parallax and at Nuts & Volts for all their support for me and for The Spin Zone.