Pitcher to Catcher speaker

[Nikki2994]

I am trying to figure out how to create something that when a certain sound plays from a small speaker another speaker will finish it. So essentially you push a button lights turn on play part of a song and when it ends another thing hears it and finishes it. Think like a toy. Can anyone help me? I can figure out how to get something to play I just think it would be better if I could also get one to listen instead of another button. It's just extra

 

[kellys_eye]

Edge (slope) detector.

A circuit that detects when audio is being played (and switches it's output 'high') then, when the audio stops, switches it's output 'low'. You can then use the changing state - i.e. high-to-low transition - to activate the second audio stream.

You aren't so much 'listening' (from an external pespective) for one audio signal to stop but detecting when the ORIGINAL signal has finished and creating a signal to activate the second audio stream.

 

[danadak]

An old technique for something like this is to add an inaudible signal
to the audio stream, and detect it on the other side to trigger its player.
Often used was a PLL on the downstream side of the added trigged
signal in the source player.

Classic was a 567 PLL tone detector.

https://archive.org/download/bitsav...s_5800304/1972_Signetics_PLL_Applications.pdf

https://web.mit.edu/6.115/www/document/lm567.pdf


Regards, Dana.