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From time to time the photo module in MagicMirror hangs. I used to restart it manually by logging into the Raspberry and using the command “pm2 restart mm”. Now I want to make it so that it automatically restarts when I scan the NFC tag stuck to the back of the monitor.

So I divided big problem to smaller ones:
1. Restart MM,
2. Connection HA to MM machine,
3. Automation when HA apk scan tag,
4. Stick the NFC tag to the monitor xD

1. Restart MM – Easy

pm2 restart mm

2. Connection HA to MM mashine

HA needs to let MM know to shut down for a while, so I guess the easiest way to do this is with mqtt broker.
I have used before Mosquitto, so I will use it.

MM site:
I created 2 files in my home directory: restartmm.sh and restartmm.py

restartmm.sh:

#!/usr/bin/env python

sleep 20
python /home/pi/restartmm.py &

restartmm.py basen on mqtt-screen-power project:

mqtt_host = "192.168.xxx.xxx"
mqtt_port = 1883
mqtt_topic = "/screen/restart"
mqtt_username = "xxxxxxxx"
mqtt_password = "xxxxxxxx"
power_on_command = "pm2 restart mm"
power_off_command = " "


import paho.mqtt.client as mqtt
import subprocess


def on_connect(client, userdata, flags, rc):
    # The callback for when the client receives a CONNACK response from the server.
    print("Connected with result code "+str(rc))

    # Subscribing in on_connect() means that if we lose the connection and
    # reconnect then subscriptions will be renewed.
    client.subscribe(mqtt_topic)


def on_message(client, userdata, msg):
    # The callback for when a PUBLISH message is received from the server.
    print(msg.topic+" "+str(msg.payload))
    if str(msg.payload) == "ON":
        subprocess.Popen(power_on_command,
                         shell=True, stdout=subprocess.PIPE)
    else:
        subprocess.Popen(power_off_command,
                         shell=True, stdout=subprocess.PIPE)


client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message

client.username_pw_set(mqtt_username, mqtt_password)
client.connect(mqtt_host, mqtt_port, 60)

# Blocking call that processes network traffic, dispatches callbacks and
# handles reconnecting.
# Other loop*() functions are available that give a threaded interface and a
# manual interface.
client.loop_forever()

Both files chown is 755. Autostart with command “crontab -e” – “@reboot sh /home/XXXXX/restartmm.sh”

HA site:

HA configuration.yaml

switch:
  - platform: mqtt
    name: "MM restart"
    command_topic: "/screen/restart"

automations.yaml:

- alias: turn_off_restart_mm
  trigger:
    platform: state
    entity_id: switch.mm_restart
    to: 'on'
    for:
      seconds: 1
  action:
    service: switch.turn_off
    entity_id: switch.mm_restart

3. Automation when HA apk scan tag,

HA automations.yaml:

- alias: mm_tag
  initial_state: true
  trigger:
  - platform: tag
    tag_id: 7275ecff-27a1-4c4d-a7fd-69647998dbf8
  action:
  - service: switch.turn_on
    entity_id: switch.mm_restart

4. Stick the NFC tag to the monitor. Formality.