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.
NXP Semiconductors' BSS138PS,115 is a N-CHANNEL FET with 60V DS breakdown voltage and 0.32A max drain current. Ideal for switching applications, it features a 1.6 ohm max on-resistance and operates in enhancement mode. The transistor comes in a small outline package with GULL WING terminals, making it suitable for surface mount designs.