ATMEGA328P-AU by Microchip: 8-bit RISC CPU, 20 MHz clock, 23 I/O lines. Ideal for industrial applications with SPI, TWI, USART connectivity and low power mode. Features include 2048 RAM bytes, 1024 EEPROM size, and 16384 ROM words.
ULN2803ADWG4 by Texas Instruments is a peripheral driver with 8 functions, open-collector output characteristics, and built-in transient protections. It operates at temperatures ranging from -40 to 85°C and has a max supply voltage of 3V. Ideal for applications requiring sink current flow direction in a small outline package style.