Can a light dimmer be activated by noise: Advice for novice

Thread Starter

mondo_johns

Joined May 13, 2011
3
I was wondering if anyone out there could help with this.

What I'd like to do is to have a set-up that automatically dims the lights in a room when it picks up noise in said room. ie. there's a direct correlation between light and noise: the louder it gets, the darker it gets.

As I said I'm a complete novice to this kind of stuff and would much appreciate any help and advice with this project.

Thanks
 

Bernard

Joined Aug 7, 2008
5,784
Yes. If you use a " Dawn to Dusk " light control yhen you can supply the controlling light with a LED shining into its window. Use Bill Marsden's flickering LED circuit to control the LED; uses music as input, noise should work. How long should dimming last after noise stops?
 

Thread Starter

mondo_johns

Joined May 13, 2011
3
thanks for your replies.

Bernard, there should be an almost direct correlation. so if the noise slowly petered out then the light would slowly get brighter again. or if there was a sudden change in volume they would flick back up quickly(you get the idea)

where can i find out about Marsden's flickering LED circuit??

thanks again
(i'll use protection next time)
 

Bernard

Joined Aug 7, 2008
5,784
A slightly simpler way: I connected a Radio Shack electret condenser mike, 270-092A, to a RS Mini Amplifier-Speaker, 277-1008C, & from the external output jack connected two diodes, a 1.2k resistor & a red LED. Dropping a quarter an a hard floor, killed a 100W bulb[ turned it off].May want to add some filtering to output for longer delay. The amplifier is still stocked by RS.
 

Bernard

Joined Aug 7, 2008
5,784
Another version: Breadborded & tested using one TL 082 OP AMP, with an 8 V battery supply, 4, AA Ni-Cd & 2 AAA alk. Parts were those within arms reach, but generally in right range. I wanted a 100 K pot, but the 30 K already had leads. One OP AMP was a little low on gain, so used second OP AMP as gain of 100 +_, LED responds to breathing, or rattling keys in pocket. Suggested power supply - a 9 V AC/DC adapter.The Dimmer from ACE Hardware, has a plug in light shield, which makes mounting LED easy with cork washer. Woops- lost C5, 220 uF, + to junction D2 & R7; - to gronnd. If a longer than 2 sec. delay is desired, then add transistor as emitter follower [ MPSA 14 etc ].
 

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