yetanotherchris Posted January 4, 2007 Report Share Posted January 4, 2007 Ok folks, I'm preparing my second reworking of an old guitar, and I've had a bit of an odd idea for a kind of 'killswitch/tremolo'. Basically what I want to do is have a toggle switch on the guitar where the output goes to the jack. In one position the output just goes to the jack as normal. Consider it the 'off' position for the 'tremolo'. In the other position the output is rerouted through an LDR (Light Dependent Resistor) mounted on the front of the guitar. When there's lots of light hitting the LDR, the signal is unaffected. But if there's little/no light (ie when I pass my hand over the LDR) the volume is reduced/cut. What I really need is some advice on components/wiring. For example, Maplin stocks loads of LDRs, but I don't know which would work for my purposes. http://www.maplin.co.uk/SEODynamicPages/mo...asp?ModNo=35962 Also, how best to wire in the LDR and toggle switch, and whether any other components would be needed... any advice would really be appreciated! Thanks folks! Chris Quote Link to comment Share on other sites More sharing options...
rhoads56 Posted January 4, 2007 Report Share Posted January 4, 2007 .... what happens when the lighting guy turns the red lights on you, and the sound just dies? Or he hits the strobe lights? Quote Link to comment Share on other sites More sharing options...
weezerboy Posted January 4, 2007 Report Share Posted January 4, 2007 correct me if im wrong...but the LDR would work opposite to that, with the volume rising as you cover it. Quote Link to comment Share on other sites More sharing options...
Mr Alex Posted January 4, 2007 Report Share Posted January 4, 2007 The LDR's resistance will increase as you reduce the light, but you'd have a hard time getting it to zero resistance. In full sunlight all the ones I have don't even get close. LDR's are the worst toleranced part I've ever come across too. Quote Link to comment Share on other sites More sharing options...
yetanotherchris Posted January 7, 2007 Author Report Share Posted January 7, 2007 ... Putting worries about the lighting guy and the tolerances aside... any advice? Quote Link to comment Share on other sites More sharing options...
psyche Posted January 7, 2007 Report Share Posted January 7, 2007 Hi there, the best you can do is to build an active circuit using the ldr as a "controller".Active circuit means that it needs a 9 volt battery.Do you have space for a 9 volt battery in the guitar?Answer me and i can give answers and even a circuit for the job.But have in mind that you have to move your hand pretty close to the ldr in order to affect the light which goes the LDR.I think that the best thing that would the job would be somekind of a "proximity" sensor which is used by some synths to control some parameters. Quote Link to comment Share on other sites More sharing options...
yetanotherchris Posted January 11, 2007 Author Report Share Posted January 11, 2007 Hi there, the best you can do is to build an active circuit using the ldr as a "controller".Active circuit means that it needs a 9 volt battery.Do you have space for a 9 volt battery in the guitar?Answer me and i can give answers and even a circuit for the job.But have in mind that you have to move your hand pretty close to the ldr in order to affect the light which goes the LDR.I think that the best thing that would the job would be somekind of a "proximity" sensor which is used by some synths to control some parameters. Thanks for your post Psyche, I think I'll be putting this one on the back burner for now. If I do plan on continuing I'll pick up the post where I've left off. Cheers, Chris Quote Link to comment Share on other sites More sharing options...
Prostheta Posted January 11, 2007 Report Share Posted January 11, 2007 Bias the upper and lower conditions using a pair of miniature preset potentiometers - one in series to add a minimum resistance, and one in series to provide a maximum. Quote Link to comment Share on other sites More sharing options...
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