Budget around 75 minutes. I'm assuming a tablet with the Home Assistant Companion app installed, set up along the lines described in Module 16.

A Real-Life Problem: A Tablet That Falls Asleep and Loses Sound

A tablet configured with default settings dims its screen after a minute of inactivity, and the OS mutes background app audio after a while, depending on battery-saving settings. The effect: a TTS announcement sent to the tablet at night doesn't wake it back up, and either doesn't play at all, or plays silently to a dimmed screen. The fix is deliberately configuring kiosk mode, disabling battery optimization for the HA app, and explicitly waking the screen before an announcement, instead of relying on the system's default settings.

Setting Up the Tablet as a Fixed Communicator

Waking the Screen Before an Announcement

script:
  kitchen_tablet_show_visual_announcement:
    alias: "Kitchen tablet: show a visual announcement"
    icon: mdi:tablet
    mode: queued
    max: 5
    fields:
      message:
        description: "The message to display and speak"
        example: "Someone's at the gate"
    sequence:
      - action: notify.mobile_app_kitchen_tablet
        data:
          message: "command_screen_on"
      - delay: "00:00:01"
      - action: script.turn_on
        target:
          entity_id: script.home_announcement_with_music_ducking
        data:
          variables:
            speaker: media_player.kitchen_tablet
            message: "{{ message }}"
      - action: notify.mobile_app_kitchen_tablet
        data:
          message: "command_activity"
          data:
            intent_action: "android.intent.action.VIEW"

command_screen_on is a Companion app command that wakes the screen remotely: the exact name and availability of this command depends on the app version, so check the current mobile_app integration documentation for your platform. The script deliberately calls the previously built script.home_announcement_with_music_ducking from Lesson 6, instead of duplicating the TTS logic: that's good practice, reusing components instead of copying code between scripts.

Showing the Camera After a Doorbell Press, Tying Back to Module 21

automation:
  - alias: "Tablet: show the intercom camera after a doorbell press"
    id: tablet_show_intercom_camera_on_doorbell
    mode: single
    triggers:
      - trigger: state
        entity_id: binary_sensor.doorbell_button
        to: "on"
    actions:
      - action: notify.mobile_app_kitchen_tablet
        data:
          message: "command_screen_on"
      - action: notify.mobile_app_kitchen_tablet
        data:
          message: "command_dashboard"
          data:
            dashboard: "/lovelace-outdoor/intercom-camera"

This directly ties back to Module 21's doorbell and intercom lesson: the tablet automatically switches to the camera view whenever someone presses the doorbell, instead of requiring you to manually open the app. After a set amount of time, it's worth adding an automation restoring the default dashboard, so the tablet doesn't stay stuck on the camera view permanently.

Night Mode: Dimming and Touch Lock

automation:
  - alias: "Tablet: night dimming"
    id: tablet_night_dimming
    mode: single
    triggers:
      - trigger: time
        at: "22:30:00"
    actions:
      - action: notify.mobile_app_kitchen_tablet
        data:
          message: "command_screen_brightness_level"
          data:
            data:
              brightness: 15

  - alias: "Tablet: restore brightness in the morning"
    id: tablet_restore_brightness_morning
    mode: single
    triggers:
      - trigger: time
        at: "07:00:00"
    actions:
      - action: notify.mobile_app_kitchen_tablet
        data:
          message: "command_screen_brightness_level"
          data:
            data:
              brightness: 180

Night dimming is part of the silence mode built in Lesson 9: a tablet blasting harsh white light at 2am in the entryway is disruptive all on its own, regardless of sound. Adjust the brightness values (0-255 on a typical Android scale) to your screen and ambient lighting.

Fully Kiosk: What You Actually Control Over MQTT, and What License It Needs

Fully Kiosk Browser has supported MQTT natively since version 1.34, letting you control the tablet without a middleman REST integration. Over MQTT you can read battery state, screen state, and motion detected by the front camera, and send commands: turn the screen on/off, set brightness, set volume, load a specific URL, or launch a given app.

The alternative to Fully Kiosk is the official Home Assistant Companion App in kiosk mode, simpler to set up, but with fewer technical options: it doesn't offer, for example, as extensive an MQTT surface, or the hundreds of settings available in Fully. For a simple panel with no extra requirements, it's a faster start; for full control over screen behavior, the screensaver, and motion detection, Fully Plus is still the richer option.

Mounting the Tablet: Wall Brackets and Permanent Power

A tablet working as a fixed home communicator, unlike a tablet for regular use, should be permanently powered from the mains, not the battery: continuously displaying a dashboard plus periodic voice announcements drain a battery quickly, and a tablet that dies at a critical moment (a security alert, say) defeats the whole point of its role. Dedicated wall mounts with built-in power (available for popular tablet models) solve this neatly, without a visible cable trailing across the wall.

Child Safety Around a Wall Tablet: Access Restrictions

A tablet mounted within reach of children, showing the home dashboard, is worth securing according to the practices from the Home Assistant maintenance module: a dedicated, restricted user account instead of an admin account, and a dashboard showing only functions safe for a child to control (lighting, music), with no access to gate or alarm settings. Fully Kiosk, covered in this lesson, additionally lets you lock access to the tablet's own system settings, preventing an accidental exit from kiosk mode.

The Tablet as an Intercom Between Rooms

Beyond showing a dashboard and system announcements, a tablet configured per this lesson can serve as a simple intercom: a voice message recorded on one tablet (in the kitchen, say) and played on another (in a child's room, say), replacing shouting across the house. This requires an additional automation recording a short message and playing it back on the target device, built on the same TTS and media_player mechanisms covered earlier in this module.

Power Consumption of a Tablet Running 24/7, and Power-Saving Modes

A tablet running around the clock as a fixed communicator uses more power than one used occasionally, though over a year that's usually a small cost compared to other household devices. It's worth considering automatic screen dimming at night (tying back to the night mode from this lesson's main content) not just for household comfort, but to reduce power use and extend the display's own lifespan, especially with OLED technology, which is prone to burn-in under a constant, bright image.

Integrating the Tablet With the Video Intercom System From Module 21

A tablet configured as a home communicator in this lesson naturally ties into the doorbell automation from Module 21: the doorbell camera's feed can be shown on the tablet automatically instead of requiring you to manually open the app, giving you an almost instant view of whoever's at the door on a device that's already hanging on the wall, right where household members can see it.

Alternative Accessories: Stylus and Tempered Glass

A tablet used as a fixed communicator, touched regularly by multiple household members, benefits from extra protection: tempered glass guarding against scratches under frequent use, and, if the tablet also gets used for notes or drawing, a stylus compatible with that model. It's a small but practical detail that extends the lifespan of a device running nonstop for years in a spot accessible to the whole family.

Recycling an Old Tablet as a Home Communicator

A tablet set up as a fixed home communicator doesn't have to be a new purchase: an older tablet, already too slow for everyday, intensive use but still functional, works perfectly well in this role, since displaying a simple Home Assistant dashboard doesn't need much compute power. It's a practical way to give a second life to hardware that would otherwise end up in a drawer.

How to Test This Lesson

Common Mistakes

Practical Task

Key Takeaways

What's Next

Next lesson: The TV as an Information Hub: the TV App, Dashboard, Cameras, Notifications, and Remote Limitations. A similar topic, a different medium, different limits.