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How to get the right voltages to make a circuit with laser pointer, LDR and motor? Answered

In short, it is for a uni project, and what I would like to do is shine a light (laser or white light) onto a prism that would have a LDR to detect the light and trigger a motor - the motor is attached to the prism to make it spin and refract the light to the next prism for a chain reaction mechanism to happen (I'd have 3 of them operating in a circle, maybe..)
What I really need to know is what types of components to buy as there seems to be different kinds of every one, different voltages. (for example, how strong a laser do I need to be detected by the LDR, etc etc...) Don't want to fry anything!
Thank you very much for you help! :)



7 years ago

If you're using a laser, you need only a very very small one to detect on an LDR.

Your biggest problem is going to be positioning the prisms - what are you going to use for servos to point them ?



Answer 7 years ago

Hi Steve,
I'm afraid I don't really know, I was thinking of step motors maybe? In order to reduce the speed of the rotations to make the next detection/triggering easier...
Also, can I link the LDR and the motor through a relay or will it have to be through Arduino?


Answer 7 years ago

An instrument to measure spectra replaces a prism with a diffraction grating.
Depending on resolution a linear array is used but you could fine step the
grating to shoot an LDR. Do you know the color response of your LDR ?



Answer 7 years ago

I think you need to draw this thing up and decide how you are going to get to your end point.

Ask yourself.:

You have a laser source, not pointing at the LDR. Now, how are you going to bring the laser to bear on the LDR ? What, algorithmically, will you need to do ?