Thinking of how to do a wired intercom. Need at least three stations, expandable to four. I have CAT5 cable (four pairs, 8 wires) running to the locations where the remotes need to be. I would like to make it so any remote could do n "All Page" that comes out all speakers in all the other remotes.
I don't need selective calling, just a Push-to_Talk switch at each remote such that audio from the local speaker-mic comes out of all the other speakers.
I'm thinking that an LM386 at each remote would work. When the local PTT switch is pushed, I would use the local speaker as a mic, amplify it using the LM386, and switch the LM386's output onto the common speaker bus. That way, only a single LM386 is active at one time, and you never have multiple LM386's driving the speakers at the same time. All the speakers in the remotes can be wired in parallel.
I can send 12Vdc to each remote to power the LM386s on the CAT5. Since it is a Push-to-Talk, Release-to-Listen, type of system, it can't be used for eavesdropping. None of the LM386s need to be powered when the system is idle.
Is the LM386's max gain of 200 sufficient to amplify a 16Ω speaker used as a mic?
Can a LM386 drive three 16Ω speakers wired in parallel?
Comments?
Better suggestions?
Any body have a link to a pre-built system that works this way? (No power-line wireless stuff)
I don't need selective calling, just a Push-to_Talk switch at each remote such that audio from the local speaker-mic comes out of all the other speakers.
I'm thinking that an LM386 at each remote would work. When the local PTT switch is pushed, I would use the local speaker as a mic, amplify it using the LM386, and switch the LM386's output onto the common speaker bus. That way, only a single LM386 is active at one time, and you never have multiple LM386's driving the speakers at the same time. All the speakers in the remotes can be wired in parallel.
I can send 12Vdc to each remote to power the LM386s on the CAT5. Since it is a Push-to-Talk, Release-to-Listen, type of system, it can't be used for eavesdropping. None of the LM386s need to be powered when the system is idle.
Is the LM386's max gain of 200 sufficient to amplify a 16Ω speaker used as a mic?
Can a LM386 drive three 16Ω speakers wired in parallel?
Comments?
Better suggestions?
Any body have a link to a pre-built system that works this way? (No power-line wireless stuff)
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