Use a speaker as a Microphone

Other Hardware Sensors
1

Hello,
How can I use a Speaker as a microphone or sound sensor to receive voice commands.
Thanks

2

This is done by using an amplifier for the tiny signal the speaker puts out. You have to be very careful with that circuit as usually the currents are very small so it's hard to get a useful signal from a speaker.

Why do you want to use the speaker and not a microphone? The majority of speakers won't provide a clear enough signal to recognize voice commands. Speakers are optimized to generate sound and not to sense it. I doubt that you can get a signal out of a standard speaker to actually recognize a voice command.

3

you need a very small speaker, about 2" / 50 mm across. a speaker is a dynamic mic, a dynamic mike is a low grade speaker.

4

pylon:
This is done by using an amplifier for the tiny signal the speaker puts out. You have to be very careful with that circuit as usually the currents are very small so it's hard to get a useful signal from a speaker.

Why do you want to use the speaker and not a microphone? The majority of speakers won't provide a clear enough signal to recognize voice commands. Speakers are optimized to generate sound and not to sense it. I doubt that you can get a signal out of a standard speaker to actually recognize a voice command.

Thank you
It used in Trap Shooting and clearance of voice is not important. just sensing a signal by shooter is enough.

5

Thanks a lot

6

Hi Navab; there is no reason why you cant use a speaker as a microphone; however the impedance of a speaker (typically 3 - 60 ohms) is a poor match to any arduino input, and the signal you get will be very small.

An electret microphone may give you enough output with very little amplification so why not just use one of those?

If you really MUST use a speaker then I'd suggest you get a matching transformer or small mains transformer - say 240 - 3V (ie 80:1) which again may give a big enough signal. However you would need to disconnect it somehow if you are also intending to use the speaker for output, as the big signal to the speaker would fry anything connected to the transformer.

7

The smaller the speaker the higher the frequency range and likely more sensitive generally, which helps as a microphone. However you lose bass and power handling used as a speaker. This is why speakers are rarely used as microphones.