Concept

I created a small demonstration video to show you how it works.

The user interface features 5 tiles, each showing the icon of a scene, as a vertical list. You can navigate the list by swiping the UI up and down. The active lighting scene is highlighted in bright green (same color scheme as my main home automation touchscreen). Activating a scene can be done by ticking it.

The state of the control is synchronised with home assistant via MQTT.

The watch

Watch hardware

The watch features everything to make it a good remote control, except perhaps battery capacity. It's a bit small to use as such, but perhaps a bar shaped enclosure and larger lithium battery could fix that.

Lilygo twatch 2020 feature sheet

Mechanical integration

I hope to integrate the display into a blind faceplate.

90's niko switchplate formfactor

I'm aiming for the more modern cover plates, which should be possible. But fitting it in the older (1990's style?) plates will be easier since it won't require removing the display from the chassis.

Modern Niko wall socket

I tried to remove the display panel from the watch a few times by applying heat to soften the glue. This is how smartphone glass panels are removed. That did not work with the amount of heat I dared applying. At least I didn't burn the display.

Proof of concept development

I pushed the hacked watch firmware to http://www.github.com/thouters/MoodControlPoc in case you want to have a look or replicate this.

As of 2020/12/24, it can be called 'proof of concept', with these issues still present:

• The watch still sleeps, and after waking it up, it has to reconnect to WiFi and the MQTT broker
• you can still uncheck the icons (implemented as checkable image buttons).
• the green color (state indicator) (as server updates are received) is not reflected on the icons

Adding icon images

I have 5 lighting scenes, and each has an associated icon.

track-light icon converted to png and bucket-filled to white

I followed these steps to get them into the firmware

• download the SVG vector art from the material design icons website
• import into gimp at 180x180 resolution
• bucket-fill the black parts to white
• export as png
• use img_conv.core.php to convert it to a c array
• change the include "../lvgl/lvgl.h" line to include "lvgl/lvgl.h"

I used https://github.com/lvgl/lv_utils to convert the images to LVGL-supported C arrays:

php img_conv_core.php "name=book_open_page_variant&img=book-open-page-variant.png&format=c_array&cf=true_color_alpha"

development testing

to verify the watch sends status updates

mosquitto_sub -h hass -u mqtt -P mqttpass  -t twatch -v
mosquitto_pub -h hass -u mqtt -P mqttpass -t twatch -m "TV"

Integration with Home Assistant

I created two automations in Home Assistant that feed back the state of the watch UI and the state of the input_select to each other.

- alias: moodliving_mqtt_out
  trigger:
  - platform: state
    entity_id: input_select.mood_living
  action:
    service: mqtt.publish
    data_template:
      topic: "twatch"
      payload: "{{ states('input_select.mood_living') }}"
- alias: moodliving_mqtt_in
  trigger:
    - platform: mqtt
      topic: "twatch"
  action:
    service: input_select.select_option
    data:
      entity_id: input_select.mood_living
      option: "{{ trigger.payload }}"

Existing opensource touch UI's

If I were to take this project to the next level, building upon the work of existing open source home automation projects is essential.