HC-SR04 Ultrasonic Distance Sensor Module Arduino For Beginners This MQ-2 Smoke and gas

This MQ-2 Smoke and gas detector module works with 5V power

The battery holder puts the batteries in series so that you have 4x the voltage of an AA battery

and security devices

can be measured since the waves can penetrate through the water

The 5V Single-Channel Relay Module high level or low level trigger relay is a great little tool for anyone working with Arduino

HC-SR04 Ultrasonic Distance Sensor Module Arduino For Beginners This MQ-2 Smoke and gasHC SR04 Ultrasonic Sensor The HC SR04 Ultrasonic Sensor Module is a popular tool for measuring distance and detecting objects. Its small, easy to use, and combines everything you need: a transmitter, receiver, and control circuit in one module. It works like a sonar, sending out sound waves to measure the distance to objects, just like how bats and dolphins sense their surroundings. This makes it an ideal ultrasonic sensor module for robotics and IoT