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here's a noob question, I am trying to build a controller for the Olympic double trap shooting sport. This means activing 2 of 3 target throwing machines whenever a shooter calls PULL in the microphone placed in front of him. There are 5 stations, each has its own microphone, my Python code knows which station the shooter is standing on, how would I connect 5 microphones to the GPIO so that my Python program only activates the microphone where the shooter is standing and leaves the other 4 microphones off. Also what would I need between the microphone and the GPIO to change the PULL audio command to an activate signal that emulates a button press.

Kind regards

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I've made the presumption that there is only ever one active shooter at a time. Introducing multiple shooters would substantially increase the difficulty.

The mics that you've referenced (goodness me those are expensive things!*) have, as far as I can tell from the manufacturer's deeply unhelpful website, a simple 2 pin connection. That being the case you should be able to use something similar to the 'Keyes Microphone Sound Detection Sensor' board. This comes with a 2 pin microphone soldered to the board. Desolder this and replace it with the lead to your microphone, or a suitable socket that you can plug the mic into. Repeat with all 5 mics.

The digital output level for the sensor is 5V. This is too high for the Pi's 3.3V GPIO pins, and may cause a magic smoke release. You can use something like the Adafruit 8-channel Bi-directional Logic Level Converter to convert the 5V output down to a safe 3.3V.

Connect each D0 output pin on the sensor board to a 5V pin on the logic level converter. Connect each corresponding 3.3V pin to a Pi GPIO pin.

You adjust the sensitivity threshold of the audio sensor boards using a small screw on the top. When the audio level at a microphone crosses this threshold, the output from the corresponding sensor board is driven high (5V). The logic level converter converts this to 3.3V and outputs it to a GPIO pin. Use Python to create some kind of association between stands and pins. If stand [x] is in use, listen to GPIO pin [x]. When it goes high you stop listening to the pin, fire your clay, wait for a second or two till the racket dies away, then start listening to the pin again for the next 'PULL'.

*Gadzooks those are expensive microphones. If it were me, I'd experiment with something like these EKULIT EMY-6027P/N-R-42 IP67 rated cheap things, possibly in a plastic cone to reduce off-axis audio from leaking in.

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  • Your assumption is correct, as in, a squad consists of six shooters and everyone takes their turn to shoot, one shooter at a time. My Python code knows what station's turn it is to shoot. Many thanks for the help, exactly the info I was looking for.
    – Shalimar
    Feb 16 '16 at 4:06
  • Instead of connecting the mics directly to the sound detection circuit I intend to connect female guitar jacks to the circuit board, so I can attach them to the controller box, and connect the mics to male guitar pickup jacks, which I can then attach to the outside of the controller box.
    – Shalimar
    Feb 16 '16 at 4:18

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