I started the fully integrated Arduino Uno shield schematic and renamed the project to Arduino RFID SD Relay Shield.
Completed:
- Added PN532 RFID IC, microSD socket, relay, relay driver, flyback diode, MP1584 buck, 3.3 V LDO, SPI level shifter, terminal blocks, Arduino header placeholders, and support passives.
- Wired the initial 28 V input, 5 V rail, 3.3 V rail, SPI level-shift path, relay driver, and relay contacts.
- Created:
Important: the schematic is not layout-ready yet. Review still reports unresolved floating pins, mainly because the MP1584 buck support network and PN532 crystal/antenna/matching/reset circuitry need to be completed from the datasheets before moving to PCB layout.