diff --git a/homeai-esp32/PLAN.md b/homeai-esp32/PLAN.md
index 0816133..8c8f377 100644
--- a/homeai-esp32/PLAN.md
+++ b/homeai-esp32/PLAN.md
@@ -67,6 +67,7 @@ ESP32-S3-BOX-3
 | Sensor dock I2C SCL | GPIO40 | sensor bus (AHT-30, AT581x radar) |
 | Sensor dock I2C SDA | GPIO41 | sensor bus (AHT-30, AT581x radar) |
 | Radar presence output | GPIO21 | AT581x digital detection pin |
+| Battery voltage ADC | GPIO1 | dock battery holder, voltage divider (×2) |
 
 ---
 
@@ -117,6 +118,14 @@ Optional accessory dock connected via secondary I2C bus (GPIO40/41, 100kHz):
 - **AT581x mmWave radar** — presence detection via GPIO21, I2C for settings config
 - **Radar RF switch** — toggle radar on/off from HA
 - Radar configured on boot: sensing_distance=600, trigger_keep=5s, hw_frontend_reset=true
+- **Battery monitoring** — ADC on GPIO1 with voltage divider (×2), reports voltage + percentage (Li-ion 3.0–4.2V curve)
+
+### Display Brightness
+
+Screen brightness adapts to context:
+- **Radar presence** → wakes at configurable dim level (default 30%, adjustable 5–100% via "Radar brightness" entity in HA)
+- **Voice activity** (listening, thinking, replying, error, timer) → full 100% brightness
+- **Idle timeout** → screen off (configurable 1–60 min)
 
 ### Voice Assistant
 
diff --git a/homeai-esp32/esphome/homeai-living-room.yaml b/homeai-esp32/esphome/homeai-living-room.yaml
index b0f4fcf..dc77848 100644
--- a/homeai-esp32/esphome/homeai-living-room.yaml
+++ b/homeai-esp32/esphome/homeai-living-room.yaml
@@ -147,7 +147,9 @@ binary_sensor:
     id: radar_presence
     device_class: occupancy
     on_press:
-      - script.execute: screen_wake
+      - script.execute:
+          id: screen_wake
+          brightness_pct: !lambda return id(radar_brightness).state;
       - script.execute: screen_idle_timer
 
 # --- Display backlight ---
@@ -371,22 +373,22 @@ script:
                         - lambda: |
                             switch(id(voice_assistant_phase)) {
                               case ${voice_assist_listening_phase_id}:
-                                id(screen_wake).execute();
+                                id(screen_wake).execute(100.0f);
                                 id(s3_box_lcd).show_page(listening_page);
                                 id(s3_box_lcd).update();
                                 break;
                               case ${voice_assist_thinking_phase_id}:
-                                id(screen_wake).execute();
+                                id(screen_wake).execute(100.0f);
                                 id(s3_box_lcd).show_page(thinking_page);
                                 id(s3_box_lcd).update();
                                 break;
                               case ${voice_assist_replying_phase_id}:
-                                id(screen_wake).execute();
+                                id(screen_wake).execute(100.0f);
                                 id(s3_box_lcd).show_page(replying_page);
                                 id(s3_box_lcd).update();
                                 break;
                               case ${voice_assist_error_phase_id}:
-                                id(screen_wake).execute();
+                                id(screen_wake).execute(100.0f);
                                 id(s3_box_lcd).show_page(error_page);
                                 id(s3_box_lcd).update();
                                 break;
@@ -400,7 +402,7 @@ script:
                                 id(s3_box_lcd).update();
                                 break;
                               case ${voice_assist_timer_finished_phase_id}:
-                                id(screen_wake).execute();
+                                id(screen_wake).execute(100.0f);
                                 id(s3_box_lcd).show_page(timer_finished_page);
                                 id(s3_box_lcd).update();
                                 break;
@@ -560,14 +562,12 @@ script:
 
   - id: screen_wake
     mode: restart
+    parameters:
+      brightness_pct: float
     then:
-      - if:
-          condition:
-            light.is_off: led
-          then:
-            - light.turn_on:
-                id: led
-                brightness: 100%
+      - light.turn_on:
+          id: led
+          brightness: !lambda return brightness_pct / 100.0f;
 
 # --- Switches ---
 
@@ -689,6 +689,18 @@ number:
     max_value: 60
     step: 1
     initial_value: 1
+  - platform: template
+    name: Radar brightness
+    id: radar_brightness
+    icon: "mdi:brightness-6"
+    entity_category: config
+    unit_of_measurement: "%"
+    optimistic: true
+    restore_value: true
+    min_value: 5
+    max_value: 100
+    step: 5
+    initial_value: 30
 
 # --- Sensor dock (ESP32-S3-BOX-3-SENSOR) ---
 
@@ -709,6 +721,31 @@ sensor:
             window_size: 5
             send_every: 5
     update_interval: 30s
+  # --- Battery voltage (dock battery holder, GPIO1 with voltage divider) ---
+  - platform: adc
+    pin: GPIO1
+    name: Battery Voltage
+    id: battery_voltage
+    attenuation: 12db
+    update_interval: 60s
+    filters:
+      - multiply: 2.0  # voltage divider ratio on dock
+      - sliding_window_moving_average:
+          window_size: 5
+          send_every: 5
+  - platform: template
+    name: Battery Level
+    id: battery_level
+    unit_of_measurement: "%"
+    device_class: battery
+    accuracy_decimals: 0
+    update_interval: 60s
+    lambda: |-
+      float v = id(battery_voltage).state;
+      if (v >= 4.2) return 100.0f;
+      if (v <= 3.0) return 0.0f;
+      // Simple linear approximation for Li-ion 3.0V–4.2V
+      return (v - 3.0f) / 1.2f * 100.0f;
 
 at581x:
   i2c_id: sensor_bus