[March 2013] I was at a rave Wreck beach last night and for some reason there was a shopping cart down there.  It could be debris from the 2011 Japanese Tsunami. It was a plastic shopping cart with a hexoganal (honeycomb) basket. I started thinking about how amazing it would look if each of the cells were lit up by RGB LEDs. When I got home (after being chased off the beach by a police helicopter), I designed an LED PCB to fit the shopping cart.

 

The board uses WS2803 LED driver chips. A WS2803 can drive 18 PWM channels up to 30 volts  (6 R,G,B channels).  To make sourcing parts easy I’ll use a 12v car/rv/boat battery, so each cell needs to run at 12v. This means 3 3v Blue in series, 3, 3v green in series, and 4,2v red in series. This means 9-10v per series group. If I go all the way to 12v the LEDs won’t work when the battery goes down to 11.9v due to the low operating voltage range of LEDs.

 

I CNC’d and populated the circuit boards the next day. They work very well.

 

 

 

This project calls for 121 of the circuuit boards, so I’ve spend the last two weekends running the CNC machine and soldering.