Quantity   Component name
1 × LM393 U1 Amplifier and Linear ICs / Comparator ICs
1 × BC547 Q1 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
5 × 100nF 0603 C1, C2, C8, C9, C10
4 × 470pF 0805 C3, C4, C5, C7
1 × 1nF 0805 C6
1 × 10uF 0805 or SMD electrolytic C11 or C12
1 × TRRS Jack J2 PJ-327F-5A (Get it from LCSC or Ebay/Aliexpress)
1 × 2.54mm male pin headers (breakable) 20 pins - one row is typically 40 pins
1 × 47k resistor 0805 R1, R4, R7, R9, R11
1 × ~100k to ~680k resistor 0805 (Needs a bit more testing) R2, R3
1 × 100k resistor 0805 R5
1 × 120k resistor 0805 R6
1 × 1M resistor 0805 R8
1 × 2k2 resistor 0805 R10
1 × 470k resistor 0805 R12
1 × 6k8 resistor 0805 R13
4 × 2.54mm female jumpers To select which pins are input, output and ground in the minijack