What is it?

This is an extremely small NFC RFID Reader PN532 Breakout Board with Card Proximity Sensor. It is possibly the smallest PN532 reader board on the market. Most NFC breakout boards on the market are not optimized for size like this one. It measures only 30mm x 18.4mm.

Instead of using a 4-layer board, I designed it with two 2-sided 0.8mm PCB boards soldered back-to-back in order to reduce the cost and make it more affordable. The bottom board houses the PN532 NFC chip along with supporting passives. The top board contains the fine-tuned trace antenna along with a SI1141 proximity sensor. This proximity sensor allows the user to keep the PN532 in standby mode. The PN532 can be turned on only after the proximity sensor detects that an RFID card is close by. This can drastically reduce the power consumption normally required for RFID sensing.

To use it, connect the left side headers to the I2C interface of the MCU. (SCA, SCL, INT). Then connect the right side headers to the SPI interface of the MCU, along with 3.3V-5V power and ground. The RST pin can be used to pulled LOW in order to put the PN532 to standby mode. Once the SI1141 sensor detects that a card is near, you can pull the RST pin HIGH in order to turn on the PN532 RFID reader.

This breakout board comes pre-soldered, tested and ready to use. This board runs on 3.3V logic.

Datasheet for PN532: https://www.nxp.com/docs/en/nxp/data-sheets/PN532_C1.pdf Datasheet for SI1141: https://www.silabs.com/documents/public/data-sheets/Si114x.pdf

Some open source library files: https://github.com/elechouse/PN532 https://github.com/moderndevice/SI1143_Pulse_Prox_Sensors