Based on the low-cost 8-bit ATmega328P processor, the Arduino Uno R3 board is likely to score as the most popular Arduino family member so far, and this workhorse has been with us for many years. Recently, the new Arduino Uno R4 was released, based on a 48-MHz, 32-bit Cortex-M4 processor with a huge amount of SRAM and flash memory. Additionally, a higher-precision ADC and a new DAC are added to the design. The new board also supports the CAN Bus with an interface. Two versions of the board are available: Uno R4 Minima, and Uno R4 WiFi. This book is about using these new boards to develop many different and interesting projects with just a handful of parts and external modules, which are available as a kit from Elektor. All projects described in the book have been fully tested on the Uno R4 Minima or the Uno R4 WiFi board, as appropriate. The project topics include the reading, control, and driving of many components and modules in the kit as well as on the relevant Uno R4 board, including LEDs 7-segment displays (using timer interrupts) LCDs Sensors RFID Reader 4×4 Keypad Real-time clock (RTC) Joystick 8×8 LED matrix Motors DAC (Digital-to-analog converter) LED matrix WiFi connectivity Serial UART CAN bus Infrared controller and receiver Simulators ... all in creative and educational ways with the project operation and associated software explained in great detail. All programs discussed in this guide are contained in an archive you can download free of charge from the Elektor website www.elektor.com/20619.