Let's Make Robots!

a circuit to distinguish between 3 given sound clips.

hello guys I am totally new to the world of robotics but am trying to build my 1st robo. Please tell me how to make a circuit which can distinguish between 3 given sounds clips on the basis of frequency, amplitude or the sound itself prefarably without using a PIC because i dont know much programming. Thanks.

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However I follow IG and will thus post here :)

I agree with IG in that you're taking a big leap from beginner to not-beginner, nothing personal. If you have a background in electronics it will go a long way.

With that being said, I think you're looking for something like a color organ. It separates frequencies into low, middle and high ranges and lights up a set of LEDs that represent each range. Instead of lighting up LEDs you can have the signals go to a microprocessor for further analysis of what sound was sampled.

First off, why the double post? You posted the identical question with a slightly different subject elsewhere. This will split people's responses and make it more difficult to track your question. You should revise one of your two posts and point readers to the other one so you collect all the comments in one post.

Second, if you are very new to robotics and programming, is it safe to assume you are also new to electronics in general? This project may be a bit difficult to start with, if that is the case. Have you taken a look at the Start Here robot? It doesn't have any kind of sound sensor, but you will learn alot and that can help build both the knowledge and a phycical platform on which to build the robot you want.

Finally, I'll get around to answering your question. ; j

To build a circuit that can distinguish between three sounds that are a different frequencies, you will need several components.

  1. A microphone or audio input to receive the signal
  2. An audio amplifier to boost the received signal
  3. A set of filters to differentiate the frequencies.
  4. Logic to tell additional circuitry and/or your microprocessor what frequencies are being received.

It is a lot more difficult, BTW, if you are trying to distinguish between several audio clips, all of which have a range of frequencies. That's complicated stuff. If you want to distinguish between low-frequency, mid-frequency, and high-frequency tones, then the approach above may work, but still require significant skill to design and build

Take for example, what is known as a cross over network for a speaker. A set of filters divides the audio signal from your stereo into three parts for the bass (low-frequency), mid-range and tweeter (high-frequency) speakers. You are trying to do the reverse. You want your robot to hear an audio signal, break it down into separate frequency groups, and then signal the result to your robot in some way.

I've provided a high level answer, because I think it may be more valuable for you right  now to consider if you are ready for this, or if you should start with something simpler and build your knowledge. Just about everyone on this site has gone through the process of slowly building their capabilities over time.

So my advice is to start with the Start Here robot or other simple electronics projects (light an LED, make a 555 timer circuit, etc.) and build up to what you are trying to do.

at least the tones can be generated with that same 555 timer:

is there no way to make a reciever that is def to all but a very narrow
frequency range?

if there is one could make 3 individual units, each tied to a switch that triggers
whatever it is that need to be triggered, and avoid using anything digital.

hold on, here are schematics for a transmitter/reciever pair:


if u can tweak this to change its operating frequency, you should be in buisness.