Requires a 10mmx7mm high gain electret element, 3.5MM  Stereo Jack Panel Mount Connector, and a ultra mini microswitch.   Here are the parts I used:

https://www.amazon.com/dp/B01FWWV5U4?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

https://www.amazon.com/uxcell-Electret-Condenser-Microphone-Sensitivity/dp/B01MYCFVIZ/   This is just what I had on hand and the highest gain I found on amazon.   But if you can find a higher gain, I would recommend it.  

https://www.amazon.com/Cylewet-25Pcs-Switch-Arduino-CYT1073/dp/B073TYWX86