This is Day 20 of a 30-day deep-dive into the venerable PIC16F877A microcontroller, and it tackles one of the trickier problems in embedded design: juggling three serial peripherals on a chip that only has one hardware UART. The project wires up a SIM800L GSM module, a NEO-6M GPS receiver, and an RFID reader — then orchestrates them to send an SMS containing a card scan event plus the device's latitude and longitude.

What makes this worth watching is the focus on serial communication interfacing as a discipline. You'll see how to share or multiplex UART lines, parse NMEA sentences from the GPS, send AT commands to the GSM module, and read RFID tag data — all on a constrained 8-bit MCU. These are the same skills that show up in real asset-tracking, fleet management, and access-control systems.

The PIC platform is also a refreshing change from the Arduino/ESP32 monoculture. Working closer to the registers forces you to understand baud rate generation, interrupt handling, and buffer management in a way that wrapped libraries often hide. As part of a structured series, it benefits from context built up over prior days while still being approachable as a standalone interfacing tutorial.