Need help in interfacing an electret microphone to a microprocessor and then to a speaker? Plz

[yaantey]

What I want to achieve is, I want to connect the output from electret microphone to Microprocessor (arduino) and to a speaker. So when I scream or whisper the microprocessor will detect the voltage and print out for me on the computer. And if the voltage is higher than a certain value it will on the speaker and output the voice. So, to achieve this I am using an electret microphone, a speaker with 8ohms and 0.5W and arduino Uno. I would like to know how and what I I should do to achieve this?

[DsX]

Hi,

I am not sure what this post has to do with NI hardware or software; if it doesn't you may have more luck on some more dedicated forum 😉

Anyway here is how I would go about your task (note: I am not familiar with the microprocessor (mP) you are using, so I will give you some general pointers).

Here is the basic idea: Microphone (analog signal) --> A/D converter (digitized analog signal) --> mP (signal processing - your software) --> D/A converter (back to analog signal) --> Amplifier --> Speaker

1. First of all, when talking about microphones and sound, you are dealing with analog voltage signals. So the first issue is does your mP have A/D converters built in? If not you cannot connect the microphone directly or you will most likely damage the mP. Also your mP won't be able to make much sense from an analog signal because mP usually communicate in discrete voltage levels (digital I/O) whereas analog signals vary in amplitude and frequency. Also if you are going to use an external A/D you have to take your time and select the right one for the job (there are many available but they differ in the way they transform analog to digital). Pay attention especially to synchronizing the A/D and mP clock rate otherwise you can end up loosing samples (not good).
2. On your mP you will have to design software that will do the signal processing and condition the output.
3. Again if the mP doesn't have built in D/A converters you will need external ones. Here you have to pay attention on how "powerful" the output of the D/A actually is.
4. If the D/A is not powerful enough, you will need an amplifier to which you can finally connect your speaker.

I hope you get something useful from this

Best regards,

Matej