This is a very basic four-channel summing amplifier, which collects the inputs from the shock-sensors. When a shock occurs, a trig pulse is sent to the programmable delay, which in turn triggers the flash.

The programmable delay is not much to show, as this is a home made circuit-board used for another project. Most DIY shops can provide a simple timer unit, which takes a trigger pulse and extend it for a specified time. In this case, I have used 1-5ms delay.