LIGHT UP YOUR CLOTHES WITH WEARABLE
By Pres Tuesley
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A while back, I had purchased some electroluminescent (EL) wire
from LiveWire ( www.elbestbuy.com) and used it to decorate a shirt
and a hat. The simple “on” or variable-speed flashing controller
quickly grew boring. The sequencers had up to five colors of wire,
but didn’t allow me to customize the patterns. I wanted more
control and creativity, as any self-respecting hobbyist does.
■ PHOTO 1.
Putting a voltmeter on the inverter output, I found
that it used 80 volts AC, driven at 1,600 Hz. I quickly
figured out that it was going to take something more than
a simple transistor driver to turn it on and off. I tried a
couple of miniature relays with limited success, but they
were just too bulky and power-hungry for wearable
electronics. I finally found the G3 series of opto-isolated
switches from Omron. These seemed to be the perfect
answer. Feed them a simple three volt DC signal and they
can switch up to 120 mA of 350 volts AC. Since EL wire
draws under 8 mA per meter, each switch could drive 15
meters. No moving parts, either. I breadboarded a simple
circuit with a G3VM- 2 and found that they would easily
make the EL wire turn on and off.
I had several goals in mind. I wanted to create a shirt
with custom blinking patterns. I wanted the shirt to be at
least hand-washable, so the electronics had to be
removable. I wanted the controller to be compact, so I
wasn’t dragging around a big box under my shirt. I didn’t
want to electrocute myself. I also had to work within my
own limited electronic knowledge.
I didn’t know enough about generating fairly high
voltage AC from a battery-powered source to create my
own driver. So, I decided to use the simple nine volt
battery powered inverter from Live Wire and just insert my
electronics between it and the EL wire.
I’ve used PIC processors before, so I thought this
would be a great way to expand my knowledge. They