Project Logs

Collapse

• Autodiscover MQTT in Home Assistant

  Simon Jansen • 04/24/2022 at 17:00 • 0 comments

  Because I spent so much time on this, doesn't mean we all have to. This python script configures a "doorbell" device in Home Assistant via MQTT.

  This device has:

  • A switch / toggle for the mute state. This also updates its own state;
  • A button to ring your own doorbell "cuzz ya can";
  • A trigger event as a "short button press" that you can use in automations;

    #!/usr/bin/env python
    # (c) 2022-04-24 S.E.Jansen.
    
    # Copyright (c) 2014 Adafruit Industries
    # Author: Tony DiCola
    
    #versie = "1.0"
    import time
    import paho.mqtt.client as paho
    import subprocess
    import MQTT_Config
    import GPIO_Config
    import json
    
    #call back function
    def on_connect(client, userdata, flags, rc):
        if rc==0:
            client.connected_flag=True #set flag
            print("connected OK")
        else:
            print("Bad connection Returned code=",rc)
            client.bad_connection_flag=True
    
    #Make connection with MQTT broker and
    paho.Client.connected_flag=False #Create flag in class
    paho.Client.bad_connection_flag=False #another flag
    
    client= paho.Client()                    #create client object
    client.username_pw_set(MQTT_Config.user,MQTT_Config.password)
    client.on_connect=on_connect #bind call back function
    print("Connecting to broker ",MQTT_Config.broker)
    client.connect(MQTT_Config.broker,MQTT_Config.port)	#establish connection
    client.loop_start() #start network loop
    
    while not client.connected_flag and not client.bad_connection_flag: #wait in loop
        print("In wait loop")
        time.sleep(1)
    if client.bad_connection_flag:
        client.loop_stop()    #Stop loop
        sys.exit()
    
    #the main loop starts here
    print("in Main Loop")
    
    print("Adding Doorbell " + GPIO_Config.ID + " action trigger")
    #Add doorbell button; as an action trigger
    topic = MQTT_Config.HA_name + "/device_automation/Doorbell_Button_" + GPIO_Config.ID + "/action_pressed"
    config_payload = {"automation_type":"trigger",
                      "payload": "visitor",
                      "value_template": "{{value_json.value}}",
                      "unique_id": "Doorbell_Button_" + GPIO_Config.ID,
                      "topic":topic + "/action",
                      "type":"action",
                      "subtype":"button_short_press",
                      "icon": "mdi:doorbell",
                      "device":
                          {"identifiers":[("Doorbell_" + GPIO_Config.ID)],
                           "name":("Doorbell_" + GPIO_Config.ID),
                           "manufacturer": "X",
                           "model": "001",
                           "suggested_area": GPIO_Config.location}}
    client.publish(topic + "/config",json.dumps(config_payload),0,True)
    
    time.sleep(1)
    
    print("Adding Doorbell_" + GPIO_Config.ID + " button")
    #Add doorbell; as output
    topic = MQTT_Config.HA_name + "/button/Doorbell_" + GPIO_Config.ID
    config_payload = {"name": GPIO_Config.location + " doorbell",
                   "unique_id": "Doorbell_" + GPIO_Config.ID + "_ring",
                   "name": "Doorbell_" + GPIO_Config.ID + "_ring",
                   "command_topic": topic + "/set",
                   "payload_press": "ring_short",
                   "icon": "mdi:alarm-bell",
                   "device":
                          {"identifiers":[("Doorbell_" + GPIO_Config.ID)],
                           "name":("Doorbell_" + GPIO_Config.ID),
                           "manufacturer": "X",
                           "model": "001",
                           "suggested_area": GPIO_Config.location}}
    client.publish(topic + "/config",json.dumps(config_payload),0,True)
    
    time.sleep(1)
    
    print("Adding Doorbell_" + GPIO_Config.ID + " mute switch")
    #Add doorbell; As switch. With state and command topic
    topic = MQTT_Config.HA_name + "/switch/Doorbell_" + GPIO_Config.ID
    config_payload = {
                   "unique_id": GPIO_Config.location + " mute switch " + GPIO_Config.ID,
                   "name": GPIO_Config.location + " mute switch",
                   "state_topic": topic + "/state",
                   "command_topic": topic + "/set",
                   #"payload_on": "{\"mute_set\":\"ON\"}",
                   #"playload_off": "{\"mute_set\":\"OFF\"}",
                   "state_on": "1",
                   "state_off": "0",
                   "value_template": "{{value_json.mute_state}}",
                   "retain": True,
                   "icon": "mdi:alarm-bell",
                   "device":
                          {"identifiers":[("Doorbell_" + GPIO_Config.ID)],
                           "name":("Doorbell_" + GPIO_Config.ID),
                           "manufacturer": "X",
                           "model": "001",
                           "suggested_area": GPIO_Config.location}
                   }
    client.publish(topic + "/config",json.dumps(config_payload),0,True)
    
    time.sleep(1)
    
    client.loop_stop()	#stop connection loop
    client.disconnect()	#gracefully disconnect
    client.connected_flag=False #reset flag 

   I updated the python daemon accordingly. It has to...

  Read more »

• Software and integration into the hive

  Simon Jansen • 01/12/2022 at 22:00 • 0 comments

  Now with everything connected it's time to setup the software side.

  I wrote a python script that can be run as a service. This way it has automatic startup at boot and if it fails.

  It subscribes to a "set" MQTT-topic for commands. It sends the actual state of the mute relay to a "state" topic. And when it senses the doorbell being rung, it sends a message to a "trigger" topic.

  This gives me full controll in Home Assistant.

• Assembly

  Simon Jansen • 01/12/2022 at 21:59 • 0 comments

  Ok, design is done. Now for the actual build. The Eagle board layout feature helped me to set up the components in a logical way with easy wiring. Trying to use single sided wiring as much as possible means the least crossing wires (in theory)

  Which translates to the following:

  And after one burned out transistor replacement (which was a pain to diagnose), I'm up and running!

• Figuring out schematic and components

  Simon Jansen • 01/12/2022 at 21:58 • 0 comments

  Ok. So the raspberry Pi GPIO's can only handle 3.3V max. I found some solutions that use a full rectifier and then pass the result through a linear voltage regulator. I bet this works, but it feels wrong somehow.

  I chose to go with only a single diode and a capacitor to rectify and dampen the signal.

  Some clamping diodes to VDD and GND will make sure I'm within GND - 0,7V and VDD + 0,7V. (I don't have any schottky's laying around). And a last voltage divider with two resistors to really make sure I don't go above VDD.

  First draft:

  This gave me the chance to (re)learn how to do schematics and simulation. So (quite) a few evenings later:

  Then I noticed the relays I had are double latching single coil (I had to google this too). It means they get stuck in ON or OFF position and need a reverse voltage to switch where they also get stuck.

  This turns out to be exactly what I want for the mute function that runs in series with the bell-actuator. It just means I have to learn how to do a proper H-bridge. The relays also switch on 5V and the Pi's GPIO-pins give me 3.3V. This means PNP's (I never liked PNP's, they seem upside down somehow and give me headaches)

  This also seems to work, but now I'm committed to learn something new...

  So another full day of research, and an eventual help-line to someone who knows what they are talking about:

  And the full schematic:

  I ended up using one double latching single coil relay for the mute function. The relay has two "sides". One inverted to the other. This gives me an input for the actual status, so I can check this on start-up and check if setting or resetting has worked. 

  The other relays is parallel to the doorbell button to ring it. It is a "normal" active to close 5V relay that I can operate with a transistor or a button on the board. 

  This all means the following functionality: I can ring the doorbell with a button on the board or with a GPIO-pin output. This is handy for testing and making my neighbours think I have loads of visitors. 

  I can mute my doorbell and still get a signal when the doorbell button is pressed (or when I operate the ring-relay. Using the on board button OR a GPIO-pin output).

  I also added connections for a DHT22 temperature and humidity sensor. Because, why not?

• Getting the idea

  Simon Jansen • 01/12/2022 at 21:51 • 0 comments

View all 5 project logs