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Audio Triggered by Light Answered


I'm an absolute beginner and I would appreciate some help.

I need to build a sensor that triggers sound either on Pro Tools/Logic Pro/Garage Band or any other kind of audio software when it detects a single red flash of light on it, much like the light a laser pointer would produce. The light will flash from left to right in intervals of 2.5 or 5 seconds apart. The sound is nothing too complicated. It's basically just single notes, pitched a fifth apart so for example, when the left light flashes, it needs to trigger middle C, then when the right light flashes, it needs to trigger G above middle C.

Problem is, I do not know how to go about this and where to start.

I would be deeply appreciative if someone could help me out here and point me in the right direction.

Thank you!

3 Replies

caitlinsdad (author)2014-04-29

Probably the easiest thing to do is to have an arduino output midi signals to your software. So one part of the project is to also make an arduino to midi hardware interface.

I not sure what you are doing with your lights. You mean to have an array of sensors in a row so that if you shine the laser pointer on the left sensor, it triggers a middle C and then if you shine the laser pointer on the right sensor, it triggers the high G?

You can look up any project on simple alarms with laser light detectors and get a feel for how to set that up. An arduino can the be programmed to respond to what sensor was triggered. And, you could mount a laser pointer on top of a servo to have it sweep back and forth based on the programmed timing if you want. Good luck.

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shuraifa (author)caitlinsdad2014-04-29

The lights are actually connected to an eye tracking device and software called the VNG and this is used to test whether patients have abnormalities when following a point of reference, in this case, being the lights.

These lights basically flash in two points only, left and right, and every time it flashes, the patient needs to follow it. So the middle C and G needs to sync with the lights. So yes, when the light is pointed to the left sensor, it needs to trigger middle C, and when on the right, it needs to trigger G at the precise moment the light is pointed/flashed.

When using arduino, which one would you suggest?

Thank you for replying!!

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caitlinsdad (author)shuraifa2014-04-29

Hmm, I think I did take do something like that in an eye test at the optometrist, don't recall what the setup was. As for just sounding out specific tones, the arduino is capable of doing that hooked up to a speaker so you don't need to mess with midi and a computer. I guess you are trying to modify the "goggles/glasses" type device where the lights are lit up on the eyeglass lens part? You could probably externally attach the photo light sensors with some kind of shield(encased in a straw) to focus on the lit up area or light. Go with an arduino UNO rev3 or any arduino leonardo. They interface easily by USB with PC or MAC. There are smaller form factor arduino boards that you can make it wearable on the headworn device but I think you will be better off with the full size one even if you might have long wires for prototyping.

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