Home Assistant Text Display

Home Assistant text-display is a custom component to send text to remote displays. You can send text from HomeAssistant's automations selecting the row and column where the text will be printed.

This component adds some services to HomeAssitant and currently supports serial LCD-Displays and remote displays through MySensors network.

The image is an example with a 4 rows LCD-Display showing internal/external temperature/humidity, a clock, de CPU load, CPU temperature and a alarm message. This example is explained below in this Readme.

Example configuration.yaml using a RS232 display

text_display:
  - platform: text_display_serial
    name: Controller Display
    serial_port: /dev/ttyS0
    baudrate: 14400
    rows: 4
    cols: 20

Example configuration.yaml using a MySensors remote display

text_display:
  - platform: text_display_mysensors
    name: Remote display
    rows: 4
    cols: 20
    node_id: 0
    child_id: 1

Example of automations.yaml for the image shown before as example

automation:
  # Simple clock using templates
  - alias: clock
    trigger:
        - platform: time_pattern
          seconds: 30
    action:
        - service: text_display.write_text
          entity_id: text_display.mysensors_display
          data_template:
                row: 0
                text: "CPU Load: 0.0 {{'%2.2d'|format(now().hour)}}:{{'%2.2d'|format(now().minute)}}"

        - service: text_display.write_text
          entity_id: text_display.mysensors_display
          data_template:
                text: "Line 1"
                row: 1

        - service: text_display.write_text
          entity_id: text_display.mysensors_display
          data_template:
                row: 2
                text: "Line 3"

Instalation

Copy /custom_components/* in your HomeAssistant configuration directory <config_dir>/custom_components

Detailed explanation

This component add three services to HomeAssistant: backlight, write_text and command

Service write_text

Sends some text to the display at row and column passed in the parameters row and col.

Service command

Allows send extra commands to displays using the parameter cmd as described in the table

cmd
clear	Clear screen
blink_on	On cursor blink
blink_off	Off cursor blink
cursor_on	On cursor
cursor_off	Off cursor

Configuration

The configuration in configuration.yaml depends of platform used. Valid platforms are text_display_mysensors and text_display_serial

Serial display configuration example

text_display:
  - platform: text_display_serial
    name: Controller display
    rows: 4
    cols: 20
    serial_port: /dev/ttyS0
    baudrate: 14400

MySensors configuration example

text_display:
  - platform: text_display_mysensors
    name: Remote display
    rows: 4
    cols: 20
    node_id: 115
    child_id: 1

Configuration variables

Key	Platform	Description
rows	all	Number of rows in the display
cols	all	Number of columns in the display
name	all	Custom name
serial_port	text_display_serial	Serial port where the display is connected
baudrate	text_display_serial	Default 14440
node_id	text_display_mysensors	MySensors node for display
child_id	text_display_mysensors

Configuration example with a serial display

The example uses the display NHD-0420D3Z, from Newhaven Display International, Inc. with RS-232 (TTL) protocol. In the image it has been connected to the serial port available in a RaspberryPI where HomeAssistant is running.

configuration.yaml

text_display:
  - platform: text_display_serial
    name: Display Controlador
    serial_port: /dev/ttyS0
    baudrate: 14400
    rows: 4
    cols: 20

This configuration is easy but I detected some issues in the serial communication. In a long run the display data is corrupted but it can be solved adding an extra automation to clear and refresh the display. It can be seen in the following automation examples:

automation:
    - alias: Clear display
      trigger:
        - platform: time_pattern
          hours: 6
      action:
        - service: text_display.command
          entity_id: text_display.display_controlador
          data_template:
            cmd: clear
        - service:  automation.trigger
          entity_id: automation.temperatura_display

    - alias: Temperatura display
      trigger:
        - platform: time_pattern
          seconds: 40
      action:
        - service: text_display.write_text
          entity_id: text_display.display_controlador
          data_template:
                text: "In: {{states.sensor.habitacion_trastos_119_8.state}}T {{'%2.2s'|format( states.sensor.habitacion_trastos_119_9.state)}}%  {{'%2.2d'|format(now().hour)}}:{{'%2.2d'|format(now().minute)}}"
                row: 0
        - service: text_display.write_text
          entity_id: text_display.display_controlador
          data_template:
                text: "Ex: {{states.sensor.patio_trasero_temperatura.state}}T {{'%2.2s'|format(states.sensor.patio_trasero_humedad.state)}}% "
                row: 1

        - service: text_display.write_text
          entity_id: text_display.display_controlador
          data_template:
                text: "Load: {{'%3.3s'|format(states.sensor.load_1m.state)}} CPU: {{states.sensor.patio_trasero_cpu.state|int}} "
                row: 2

Configuring MySensors remote displays

To use this component as a remote display troughn MySensors network it necessary add extra layer to MySensors V_TEXT messages.

This component needs a remote MySensors device with a S_INFO sensor type. Only a text message is supported in default MySensors implementation hence this implementation adds support for send the row and col, embedded in the V_TEXT message.

In gatewayserial.ino there is an Arduino sketch with a I2C display and a function to decode in right way the V_TEXT messages received to be printed at row and col selected as shown in the image.

Example of configuration.yaml

text_display:
  - platform: text_display_mysensors
    name: Display controlador
    rows: 4
    cols: 20
    node_id: 115
    child_id: 5

The node_id and child_id parameters are mandatory. Even though the HomeAssistant-MySensors integration detects S_INFO sensors this implementation not attach to the detected entity yet. Currently two entity are created, I'll try fix it soon.

More doc about MySensors implementation is available at mysensors.md

paulino / home-assistant-text-display