The UNO R4 was created with maximum compatibility in mind and keeps the same physical factor, compatibility with shields, and 5V operating voltage as its predecessor. The Renesas RA4M1 32-bit Cortex-M4 CPU, which powers the UNO R4, significantly increases processing speed, memory capacity, and functionality. The Arduino UNO R4 WiFi combines the processing power and exciting new peripherals of the RA4M1 microcontroller from Renesas with the wireless connectivity power of the ESP32-S3 from Espressif. On top of this, the UNO R4 WiFi offers an on-board 12x8 LED matrix, Qwiic connector, VRTC, and OFF pin, covering all potential needs makers will have for their next project. Renesas' RA4M1 (Arm Cortex-M4) running at 48 MHz powers the Arduino UNO R4, which outperforms its predecessor by three times. To support more sophisticated projects, SRAM has also been increased from 2kB to 32kB and flash memory from 32kB to 256kB. In response to user feedback, the USB connector has changed to USB-C, and an improved thermal design has allowed the maximum power supply voltage to be increased to 24V. The board includes a CAN bus and an SPI port, enabling users to reduce wiring and perform parallel tasks by connecting multiple shields. On the new board, there is also a 12-bit analog DAC.