Arduino / Microcontrollers

Board → specs and important pins

Chip
ATmega328P
I/O pins
14 digital (6 PWM) + 6 analog
ADC
10-bit ADC
Logic
5V

Best for: First board: learning, simple sensors, relays, servos

Key pins

  • •D0/D1 — UART (avoid during upload)
  • •D13 — built-in LED + SCK
  • •A4/A5 — I2C (SDA/SCL)
  • •D10–D13 — SPI
  • •Vin 7–12V or USB

ESP32 is 3.3V logic: 5V signals need a divider/level shifter. Uno/Nano are 5V but ≤20 mA per pin: relays/LED strips need transistors or drivers.