BLE iTag Button

This example shows how to use a cheap BLE keyring tag to trigger arbitrary events. An ESP32 is used, which provides a BLE peripheral.

../_images/esp32_ble_itag.png

These tags can be had for a couple of dollars each and run for several months on a coin cell. Using the BLE features of ESPHome, you can use these as small and cheap remotes to control any automation.

Quickstart

Use the configuration block below for a basic setup which will provide a binary_sensor that is momentarily turned on when the button is pressed.

You will need to find the MAC address of your tag. See the documentation for BLE Client for how to find this out. You may also wish to change the name and id fields where appropriate to suit your device(s).

Note that a maximum of three devices are supported due to limitations in the ESP32’s BLE stack.

Configuration example:

esp32_ble_tracker:

ble_client:
  # Replace with the MAC address of your device.
  - mac_address: FF:FF:20:00:0F:15
    id: itag_black

binary_sensor:
  - platform: template
    id: black_button
    name: "Black iTag Button"
    filters:
      delayed_off: 200ms

sensor:
# This entry registers and awaits notifications for the
# characteristic that signals button presses. Each time
# a notification is received, the corresponding binary_sensor
# is briefly toggled.
  - platform: ble_client
    ble_client_id: itag_black
    name: "Black iTag btn"
    service_uuid: 'ffe0'
    characteristic_uuid: 'ffe1'
    notify: true
    update_interval: never
    on_notify:
      then:
        - binary_sensor.template.publish:
            id: black_button
            state: ON
        - binary_sensor.template.publish:
            id: black_button
            state: OFF
# This entry queries the battery level. Some tags may not
# support this characteristic, you will see 'Unknown' in the
# HA frontent.
  - platform: ble_client
    ble_client_id: itag_black
    name: "Black iTag Battery"
    service_uuid: '180f'
    characteristic_uuid: '2a19'
    icon: 'mdi:battery'
    unit_of_measurement: '%'

Explanation

The first thing enabled is the esp32_ble_tracker component. This sets up the BLE stack on the device and listens for available devices.

Next, the ble_client component will listen to devices discovered by the tracker, and establish a connection to the given device when it is available.

The binary_sensor provides a template sensor which will export to the HA frontend the sensor that’s switched by the BLE tag’s button.

The first entry in the sensor component is used to configure the specific Service and Characteristic UUIDs for an iTag’s button. It also enables BLE notifications and sets up an automation to toggle the binary_sensor when a notification is received from the tag. Automatic updates are disabled, there is no point querying the tag for the device state, as we will be immediately notified when the button is pressed.

The next sensor entry listens for a well-known Service and Chacteristic that is used by many BLE devices to give battery level information. This sensor will be exposed in the HA frontend to determine the state of the tag’s battery. Note that many tags will not provide this service, so you will not see a valid value. If not, you can remove this from the config.

See Also