I've worked on this, on and off, for the past couple of weeks. Basic flasher we've got; I've been working on the audio-triggered flash.

Built the color organ, couldn't get it to do what I wanted...think the impulse of the gun just confuses the simple filters.

However, I used the front amplifier from it into the comparator input of a 555-based monostable multivibrator, and got it to work tonight... LED flashes at the rate of the gunfire playing on the smart phone. The flash seemed to skip a bit, now and then, and I thought I had a problem. Until I listened carefully to the sound, and realized the skip was where the audio looped.

Biggest problem is that there seems to be a slight delay...the flash comes slightly after the bang. Gonna look into that a bit more.

Overall, I'm not too happy with the circuit...two transistors (three when I add the power transistor for running the big LED), a 555 timer, half-dozen resistors and a batch of capacitors. We'll see.

Ron Wanttaja
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