HC-SR04 Ultrasonic Distance Measuring Sensor Module

Microphone Module

Voice & Sound Detection Module

Mini Digital Stereo Audio Power Amplifier PAM8403 Module (3Watt Amp)

Stereo Audio Amplifier Module(Dual Channel AMP AUX Amplifier Board Module DC 1.8-12V, TDA2822M 2.0)

Voice Recording & Playback Module ISD1820 with Microphones + Loudspeaker (8Ohm, 0.25Watt)

MINI LM386 Audio Amplifier Board (3V-12V Power Amplifier)

Remote Audio Relay Kit (Phone Decoder)

Waterproof Ultrasonic Range Finder Module (JSN + B02)