Annotated BOM

DesignatorDesignationQuantityMarkingUsage
BT13.6v-4.5v1n/aPower; wires to 3*AAA battery pack
C1,C5220uF1n/aBig bypass cap, Amp output
C31uF1n/aAmp gain
C2,C4,C6.1uF3104Bypass caps, RESET pin cap (C4)
D1LED_CRGB1n/aOn/off+playing indicators
J1AudioJack2_SwitchT1n/aLine out headphone jack
J2Conn_01x06_Male1n/aProgramming header
LS1Speaker, AZ40R 40mm wide1n/aWires to output speaker
R1,R22202Red Red BrownLED current limiters
R3,R510k1Brown Black OrangeBrings volume closer to ear-safe level for line out, "pull up" resistor for RESET pin
R41m1Brown Black GreenDrops volume even more before amp
RV110k Log1n/aVolume control
SW1SW_SPST1n/aOn/off power switch
SW2-SW18SPST, 6mm tall17n/aKey buttons
U1ATmega328P-PU1n/aMicrocontroller chip
U2LM3861n/aAmplifier chip
Y116.00MHz1n/aCeramic oscillator for microcontroller

Also:

  • 2 2-wire ribbon cables (or similar small gauge, stranded wire)
    • 1 7" for BT1
    • 1 3" for LS1
  • 4 battery terminal contacts for BT1
    • 2 dual spring+button wire contacts (Keystone 181)
    • 1 tabbed spring contact (Keystone 5204)
    • 1 tabbed button contact (Keystone 5226)
  • 2 DIP sockets
    • 1 28 pin for U1
    • 1 8 pin for U2
  • 4 nuts and bolts
    • 2 4/40 square nuts
    • 2 4/40 3/4" machine screws