Arduino UNO

The Arduino Uno R3 is an open-source microcontroller board based on the ATmega328 chip, designed to simplify electronics projects for beginners and professionals alike. It features 14 digital input/output pins (6 of which support PWM), 6 analog input pins, a 16 MHz ceramic resonator, a USB connection port, a DC power jack, an ICSP header, and a reset button. This comprehensive setup ensures users can start working on their projects immediately by connecting the board to a computer via USB or powering it with a DC adapter or battery. The Uno R3 replaces the FTDI USB-to-serial driver chip used in earlier models with an Atmega16U2 (or Atmega8U2 in versions up to R2) for USB-to-serial conversion. It supports dual power sources, automatically selecting between USB or an external power supply. External power can be supplied using an AC-to-DC adapter or a battery. The adapter connects through a 2.1mm center-positive plug to the power jack, while battery leads attach to the GND and VIN pins. The board operates on an external supply voltage of 6 to 20 volts, though stability and safety considerations dictate a recommended range of 7 to 12 volts. If supplied with less than 7V, the 5V output may become unstable, and voltages exceeding 12V risk overheating the voltage regulator, potentially damaging the board.