PN532 NFC/RFID

Component/Hub

The pn532 component allows you to use PN532 NFC/RFID controllers (datasheet, adafruit) with ESPHome. This component is a global hub that establishes the connection to the PN532 via SPI and outputs its data. Using the PN532 binary sensors you can then create individual binary sensors that track if an NFC/RFID tag is currently detected by the PN532.

../../_images/pn532-full.jpg

See Setting Up Tags for information on how to setup individual binary sensors for this component.

As the communication with the PN532 is done using SPI for this integration, you need to set the two switches on the board to the SPI mode (usually by setting the first one to OFF and the second one to ON). Additionally, you need to have an spi bus in your configuration with both the miso_pin and mosi_pin set.

# Example configuration entry
spi:
  clk_pin: D0
  miso_pin: D1
  mosi_pin: D2

pn532:
  cs_pin: D3
  update_interval: 1s

binary_sensor:
  - platform: pn532
    uid: 74-10-37-94
    name: "PN532 NFC Tag"

Configuration variables:

  • cs_pin (Required, Pin Schema): The pin on the ESP that the chip select line is connected to.
  • update_interval (Optional, Time): The duration of each scan on the PN532. This affects the duration that the individual binary sensors stay active when they’re found. If a device is not found within this time window, it will be marked as not present. Defaults to 1s.
  • on_tag (Optional, Automation): An automation to perform when a tag is read. See on_tag.
  • spi_id (Optional, ID): Manually specify the ID of the SPI Component if you want to use multiple SPI buses.
  • id (Optional, ID): Manually specify the ID for this component.
../../_images/pn532-spi.jpg

Example for hooking up the PN532 via SPI. Notice the position of the two switches on the right.

on_tag

This automation will be triggered when the PN532 module responds with a tag. Please note that this can be called quite often (with an interval of update_interval) as it’s triggered repeatedly if the tag is re-read many times.

The parameter x this trigger provides is of type std::string and is the tag UID in the format 74-10-37-94. The configuration below will for example publish the tag ID on the MQTT topic pn532/tag.

pn532:
  # ...
  on_tag:
    then:
      - mqtt.publish:
          topic: pn532/tag
          payload: !lambda 'return x;'

NFC/RFID Tag

The pn532 binary sensor platform lets you track if an NFC/RFID tag with a given unique id (uid) is currently being detected by the PN532 or not.

# Example configuration entry
spi:
  clk_pin: D0
  miso_pin: D1
  mosi_pin: D2

pn532:
  cs_pin: D3
  update_interval: 1s

binary_sensor:
  - platform: pn532
    uid: 74-10-37-94
    name: "PN532 NFC Tag"

Configuration variables:

  • uid (Required, string): The unique ID of the NFC/RFID tag. This is a hyphen-separated list of hexadecimal values. For example 74-10-37-94.
  • name (Required, string): The name of the binary sensor.
  • id (Optional, ID): Manually specify the ID used for code generation.
  • All other options from Binary Sensor.

Setting Up Tags

To set up binary sensors for specific NFC tags you first have to know their unique IDs. To obtain this id, first set up a simple pn532 configuration without any binary sensors like above.

When your code is running and you approach the PN532 with an NFC Tag, you should see a message like this:

Found new tag '74-10-37-94'

Then copy this id and create a binary_sensor entry as in the configuration example. Repeat this process for each tag.