Laser microphone

Hello,

im pretty new to arduino and would like to build a laser microphone. My idea was to use a laserpointer to point it on a window and let the reflected beam point on a LDR and use the values of the light intensity to play them through a 0.5 Watt 8 Ohm speaker. Now my question is how i use the LDR values to generate sound. I'm using a Ardunio 2560.

Firstly, use the laser on and off the LDR to see if it actually senses the laser. I also don't think the response will be quick enough for audio.

The next problem is the level of the returned laser. If you are able to get a direct reflection onto a very small surface area of the LDR, you will be doing well. I doubt you will be able to do this over a very short distance.

Weedpharma

Search for "Laser Spy PhotoResistor". Here's the video https://youtu.be/7bSG3ThL2L8

weedpharma: Firstly, use the laser on and off the LDR to see if it actually senses the laser. I also don't think the response will be quick enough for audio.

The next problem is the level of the returned laser. If you are able to get a direct reflection onto a very small surface area of the LDR, you will be doing well. I doubt you will be able to do this over a very short distance.

Weedpharma

Already tried to point the laser on a window and use the reflection to point on my LDR, thats working fine so far (i can register the changes if a laser is pointing on it and if the beam is moving a little bit) only need to know how to output the LDR input to a speaker

need to know how to output the LDR input to a speaker

Use an audio amplifier. Hint: a small solar cell works better than an LDR.

The video shows a good example with a strong signal - the mirror is directly on the loudspeaker. To do this off a window will require a better method. I'm sure there's interferometer circuits that can use the phase of the returned signal compared to the outgoing signal to determine the doppler shift of the laser coming off the window.

I'd go with a photodiode rather than an LDR (I think a solar cell's response is more like a photodiode). In the distant past, I built an analogue audio transmitter/receiver using not much more than a couple of 741s, a visible red LED and a photodiode. Line-of-sight with a very simple lens system over about 20 metres.

Reflected light off a window is going to be subject to external sounds too, like traffic noise, wind etc.