NFC Binary Sensor

The nfc binary sensor platform provides an easy way for you to determine if an NFC tag is presented to the reader. The tag may be identified in one of three ways:

By given unique ID (uid) – for example 74-10-37-94
By a given NDEF tag “name”, or…
By a given string contained in the tag’s NDEF message/data

Note that this platform is currently supported by the PN7150 and PN716x only; one of these components must be present in your device’s configuration in order to use it.

# Example configuration entries
binary_sensor:
  - platform: nfc
    ndef_contains: pulse
    name: "NFC 1 Tag"
  - platform: nfc
    tag_id: pulsed
    name: "NFC 2 Tag"
  - platform: nfc
    uid: 74-10-37-94
    name: "MFC Tag"

Configuration variables:

ndef_contains (Optional, string): A (sub)string that must appear in the tag’s NDEF message. May not be used with tag_id and/or uid (below).
tag_id (Optional, string): A string that identifies the tag; in effect, its name. Specifically, this looks for the Home Assistant URI encoded into one of the tag’s NDEF records and then looks for this specific string. May not be used with ndef_contains and/or uid.
uid (Optional, string): The unique ID of the NFC tag. This is a hyphen-separated list of hexadecimal values. For example: 74-10-37-94. May not be used with ndef_contains and/or tag_id (above).
All other options from Binary Sensor.

Setting Up Tags

To set up a binary sensor for a given NFC tag, you must first know either its unique ID (uid), tag ID (if it was prepared using the Home Assistant Companion app) or (part of) a string that is contained within its NDEF message.

To obtain a tag’s UID:

Set up a simple NFC component (such as the PN532, PN7150 or PN716x) configuration without any binary sensors.
Approach the NFC reader with an NFC tag. When the tag is sufficiently close to the reader, you’ll see a message in the ESPHome device’s logs similar to this:
```
Read tag type Mifare Classic with UID 1C-E5-E7-A6
```
Either:
- Copy this ID and use it to create a binary_sensor entry as shown in the configuration example above, or…
- Use the tag ID (as determined when it was prepared with the Home Assistant Companion app) to define the tag_id parameter for the binary_sensor as shown above, or…
- Choose a substring contained within the tag’s NDEF message and use this to define the ndef_contains parameter as shown in the example above. If present, the tag’s NDEF records will appear in the log on the lines just below the message shown above.

Repeat this process for each tag.

Note that, since you are able to define the NDEF message, this approach is more flexible and even allows multiple cards/tags to share the same message.