The Strobe Array is a matrix of 8 x 3 small 10W stroboscopes. Each strobe has a relay soldered into it which forces it to flash, and the relays are controlled indenpendantly by a MPLI DMX512 interface. Patterns where selected using a single DMX channel. It was built for the Highway to Hell Party at the Polytechnic School of Montreal, in october 2009 (you can see it's effect at 0:45 in this video).
The Strobe Array
The DMX Interface
The Strobe Array needs 2 DMX channels to be controlled: one to select the pattern (a value of 0 is a null pattern) and another channel to set the speed at which the pattern is to be played back. Unfortunatly, it was getting quite complex to control the exact strobing effect of each strobe. To keep things simple, I simply soldered a small 12V relay inside each strobe which shorts the potentiometer which control the rate of flashing. So by carefully adjusting the potentiometer, you can set the circuit to charge up without triggering the flash, and when the relay is closed, it starts flashing immmediatly. The short circuit on the potentiometer simulate a fully-turned potentiometer and the strobe flashes at its maximum rate.
What a mess!
The 10W strobes used
I ordered 24 small 10W strobes from Eliminator Lighting. I guess all of the similar models come from the same factory, so the challenge was to find the cheapest and make it ship in time for the party. Each of the 24 strobes needed it's own 120V power connection and 2 wires to control the relay, which explains the mess behind the frame. I didn't want to cut and rewire the strobes' power cords so I ended up strapping power bars directly onto the frame. Quick tip: don't put your fingers there when it's plugged in.