Posts: 1
Joined: Fri Feb 26, 2016 11:37 am

Audio Selector

Fri Feb 26, 2016 11:42 am

Hi All,
I currently have a mechanical switch for selecting two 3.5mm jack inputs (basically an external radio and Bluetooth receiver) for one output. Im wondering if it is possible to us a raspberry pi to do this automatically. The Bluetooth input would only be selected when there is a signal on that channel.

Posts: 295
Joined: Fri Aug 03, 2012 5:25 pm
Location: Brazil

Re: Audio Selector

Fri Feb 26, 2016 6:23 pm

You not need a raspberry pi to do it. Its is very simple task.
Can do using a analog circuity or some µC (8pin AVR or PIC) with ADC.
Raspberry Pi don't have ADC, need a external module.
Analog or µC circuity consume few µA (on stand-by), RPi need hundreds of mA.
Both, Analog and µC have same basic idea.
Sound are detected using a peak detector, if have certain level, trigger a timer that activate a relay.
If sound are constant, timer are triggered.
If no sound for some time (seconds), timer expire and cut relay.
On this case, relay need to have two reversibly contacts.

This circuity is called sound activated switch or sound activated relay

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