The Arduino Uno is a microcontroller board based on the ATmega328 Chip. It features 14 digital input/output pins which six of can be used as a PWM output, along with six analog inputs, a 16 MHz low profile crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with an AC-to-DC adapter or battery to get started.
The geeekus MQ-2 Gas Vapor Sensor module is useful for gas leakage detection for home and industry. It is suitable for detecting H2, LPG, CH4, CO, Alcohol, Smoke or Propane. Due to its high sensitivity and fast response time, measurement can be taken as soon as possible. The sensitivity of the sensor can be adjusted by potentiometer.
The geeekus PIR (passive infrared motion) Pyroelectric micro sensor is designed to work with Arduino, Raspberry Pi, micro:bit and almost any other microcontroller. This geeekus sensor is based on the AM312, which also works on 3.3V and not just on 5V (like HC-SR501) which makes it perfect for ESP8266 devices without a 5V line. It is also less prone to false triggers due to Wi-Fi interference.
The geeekus Sound Sensor module is designed for measuring sound signals like voice, claps, snaps and knocks in your surroundings. It works through sound vibrations, which cause a plate inside the sensor to bend back and forth, producing a change in voltage that can be measured. Larger vibrations means higher values.
The geeekus 1-channel solid state relay module board can be controlled by a wide range of microcontrollers such as Arduino, Raspberry Pi, AVR, PIC, ARM, PLC and etc.