Quantity   Component name
1 × RAS0510 5 Volt Relay
1 × LM311 Amplifier and Linear ICs / Comparator ICs
1 × LM7805 Power Management ICs / Linear Voltage Regulators and LDOs
1 × Potentiometer 5KOhm
1 × Recycled audio amplifier Any old audio amplifier such as bluetooth speaker or pc speaker. Try to find the datasheet to locate the output that drives the speakers. Remove all capacitors from the output.
1 × Old wifi enabled smartphone Needed for wifi connection. If bluetooth speaker is used then it is not needed.