Quantity   Component name
1 × Trinket pro
1 × MCP6041 Amplifier and Linear ICs / Operational Amplifiers
1 × BC557 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
3 × resistor 1k
2 × resistor 220k
1 × switch http://www.tme.eu/en/details/tact-64n-f/microswitches-tact-pcb/ninigi/
1 × beeper without internal sound generator http://www.tme.eu/en/details/ld-bzen-1205/electromagnetic-sounders-wo-generator/loudity/
1 × resistor 82Ohm
1 × resistor 1Ohm
1 × resistor 2Ohm
1 × MCP73831 Power Management ICs / Power Supply Support
1 × resistor 10k
2 × capacitor 10uF
1 × single-cell Li-Ion battery
1 × power switch
1 × 3D printed plastic case