pThis book is about developing projects using the sensor-modules with Arduino Uno, Raspberry Pi and ESP32 microcontroller development systems. More than 40 different sensors types are used in various projects in the book. The book explains in simple terms and with tested and fully working example projects, how to use the sensors in your project. The projects provided in the book include the following:/pulliChanging LED brightness/liliRGB LEDs/liliCreating rainbow colours/liliMagic wand/liliSilent door alarm/liliDark sensor with relay/liliSecret key/liliMagic light cup/liliDecoding commercial IR handsets/liliControlling TV channels with IT sensors/liliTarget shooting detector/liliShock time duration measurement/liliUltrasonic reverse parking/liliToggle lights by clapping hands/liliPlaying melody/liliMeasuring magnetic field strength/liliJoystick musical instrument/liliLine tracking/liliDisplaying temperature/liliTemperature ON/OFF control/liliMobile phone-based Wi-Fi projects/liliMobile phone-based Bluetooth projects/liliSending data to the Cloud/li/ulpThe projects have been organized with increasing levels of difficulty. Readers are encouraged to tackle the projects in the order given. A specially prepared sensor kit is available from Elektor. With the help of this hardware, it should be easy and fun to build the projects in this book./p