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Light Dependent resistor as volume control?

E

Electricblue

Feb 1, 2011
1,204
49
Norfolk
#1
Hi guys, at 1.45am in the morning, with my room smelling like hippies, I had a brainwave. I'm thinking of using a light-dependent resistor as a volume control in a circuit I'm making which I will possibly put in my bass.

I was thinking of having a strong light source near the bass, and a LDR acting as a volume pot, and a switch to toggle between the standard volume pot and the LDR. So basically, waving your hands about in front of it would change the volume.

Sound reasonable? I'm wondering, would a 500k ldr in parallel across the output do the job?

Thanks guys :bassist:
 
#6
Let's say that you're playing some awesome music, and your lighting guy decides to put you in the spotlight to take a solo! Now, all of a sudden, your photoresistor's impedance drops across the signal path, causing your awesome playing to go silent. You are so totally in the moment that you don't notice you are silent, and the crowd, also deep into the music, assumes the sound guy has screwed up and taken you out of the FOH mix. When the lighting guy realizes that you are silent, he takes you out of the spotlight and gives the lead guitarist a moment of glory. Now that the light on your bass has dimmed, the photoresistor increases its impedance, and you become audible again. The audience takes note of the sudden earful of awesome, but the moment for your cool solo has passed, and they divert their attention to the sound guy, who now appears to be a douche that's playing sick jokes on everyone by messing with your volume. A couple of angry drunks stumble their way back to the sound guy's booth, and beat the crap out of him for dishonoring the bass. As your gig ends, you pack up and leave, only to find the sound guy pointing a gun at you for having caused this unfortunate mishap. At this point, you realize that your photoresistor has angered your audience, ruined good music, injured your dear sound guy, and endangered your life...

:hiding:
 
#9
You could possibly do something like they used on this pedal.


The photo cell could be rigged up to produce more volume with more light, or less volume with more light. It's all in what kind you get and how you wire it.

I actually built one as an extra credit project. One of my teachers stumbled across it and wanted to see if it worked. I totally redesigned the discs to get the tremolo to sound "smooth" and it turned out OK.

It would be a mess to rig up on a bass though. If I were going to do this (and I probably wouldn't) I would probably just put the LDR on the front of the control plate near the other knobs. You could then put a pin spot next to you on stage or something like that. And then while you are playing you could "wave your hand" in front of the thing and maybe get some coolish effects. All of this is a huge stretch though. It would probably sound like crap even if you could get it to work. But what the heck. It wouldn't take long to do. And I could be totally wrong. It might just be great. Don't be in a room that smells like hippies when you try it though.
 
#10
I was thinking of using in my bass, and for a synth, possibly with an led 2 inches above the ldr to even things out a little. It's just an experiment and I have enough free time. Does the impedance drop or increase in bright light compared to in the dark?
 

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