Satyajit Ray's signature score - theme tune of Feluda as a doorbell.

Used hardware package/board with Arduino IDE 2.1.0 : MicroCore

BOM

IC1 - ATtiny13A
OPT1 - PC817
MOD1 - PAM8403 Audio Amplifier board
MOD2 - TP4056 LiPo Charge/Protection board
D1 - IN4007
LED1 - Red LED 3mm
LED2 - Green LED 3mm
LED3 - Blue Led 3mm
R1 - 10K 0.25W
R2 - 1K 0.25W
R3 - 100K 0.25W
VR1 - 50K
C1 - 0.1uF Ceramic
C2 - 1uF Polar
SW1 - Momentary push switch
SPK1 - 4 Ohm 3W
B1 - Nokia BL 5C or any 1S LiPo
H1 - 7 Pin female header
H2, H3 - 2 Pin male header
IC BASE - 8 Pin
Strip or Perf board - 10x10 holes

CAD: DIY Layout Creator 4.37.0 (1.0) | Homepage

Details: Coming soon...