Make: More Electronics

Chapter 14. Experiment 14: A Successful Protest

First I will restate the problem. Using the original concept of the Noise Protest Device that I developed in the previous experiment, if someone shouts loudly, the Protest Output will start and never stop. How can I deal with this?

One solution would be an audio filter on the microphone input so that the Noise Protest Device can’t hear its own noise but still hears when someone shouts. This would be possible, but I’m not confident that it would work reliably.

Another solution would be simply to limit the duration of the Protest Output to, say, a couple of seconds. Then there’s a pause while the Protest Output is suppressed. At the end of the pause, the Protest Output is now silent so it cannot retrigger ...