Detecting loss of wifi signal with rssi

Below is my automation to detect loss of connection to a nodemcu. I can’t get the trigger working. Tried different values in the from field which would be a signal value such as -65db. Action works fine. Any ideas? Below is my automation.

alias: Dryer off line
description: 'detect loss of rssi signal'
trigger:
  - platform: state
    entity_id: sensor.laundry_sensors_signal
    to: unavailable
    for: 00:00:00
    from: ''''''
condition: []
action:
  - service: notify.mobile_app_x_iphone
    data:
      message: Device is off line
mode: single

You don’t need the from field, just remove the from: line.

Thanks. Works great now.