Monday, August 12, 2013

Almost Perfect

The WIZ jacket finally failed in performance.

I'd been making a repair about once a weekend.  Each of the ballast resistors came loose once, and several of the solder joints to the flexible LED strip on the collars broke, but until Sunday matinee it had a flawless run.

I am still deeply satisfied, because I am not a little surprised.  It was thrown together so quickly, and I never had the in-depth testing cycle I wanted.  I didn't honestly expect it to make it through Opening Weekend without flaws.  And it failed in a good way; it didn't turn on.  If it had failed to turn off, or if the lights had gone dead along one side, the audience would have realized something was broken.  As it was, the scene was merely a little less magical than we had intended.

I'm not 100% sure of what went wrong, and this is because my procedure was diagnostic, not forensic.  When I looked at the coat, the 9V style battery jack had pulled entirely off the battery pack.  Presumably the dangling length of battery cable had gotten snagged when he was dressing for the scene.  I've taped that now, and tacked up the dangling cable as well.

But when I plugged it back in, the coat still didn't answer the controller.  The picture above was taken by a co-worker after I'd pulled all the equipment boxes out of their pockets in the back of the coat and was probing at them. 

Blinkenlights on the Arduino and the XBee Shield showed they were getting power -- so battery cable, that part of the wiring harness, and the power regulators all checked out.  When I opened up the power switch box (the Altoids tin) I confirmed power at the busses there as well.

I plugged in a USB cable and via the Arduino IDE looked to see if I was getting a serial response out (there are several serial print commands written into the coat's software for debugging purposes.)  Nothing came out.  I reloaded the Arduino software.  Still nothing.

Rebooted the control software on the laptop (a Processing application that talks to the XBee transmitter on a Sparkfun USB breakout).  At that point, the Assoc Light lit up on the coat's XBee module, the coat confirmed reception of controller commands by echoing them back through the Arduino IDE...and the lights lit.

So my best guess is that simultaneously, the Processing ap borked (possibly because someone had jiggled the USB connection and it didn't restore it properly), and the plug pulled off the battery pack in the coat.  But I can't rule out that the software on the Arduino went bad (this does happen) and it needed to be reloaded before it would work again.

Wasn't a waste of my lunch break, though.  I took the opportunity to tack down the bags holding the equipment boxes, and tack down more of the wiring.  I've been tempted to take the whole thing home and re-stitch the equipment bags and add proper velcro closures...but it works, and it made it this far, and we've only got two weekends to go.

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