Motion Sensor with ESP32

Easy 20 min $8

ESP32 Motion Sensor

PIR sensors are perfect for detecting motion. Turn on lights automatically, get notified when someone comes home, or build a simple alarm system.

PIR sensor to ESP32 wiring diagram

📋 Prerequisites

✅ ESP32 set up with ESPHome
✅ Home Assistant running

🛒 Components

Part	Description	Price
ESP32 DevKit	WiFi microcontroller	$5
HC-SR501 PIR	Motion sensor	$2
Jumper wires	3 pcs male-female	$1
Total		~$8

🔌 Wiring

Red (VCC) → ESP32 5V or VIN pin
Yellow (OUT/Signal) → ESP32 GPIO5
Black (GND) → ESP32 GND

⚙️ ESPHome Configuration

esphome:
  name: hallway-sensor
  friendly_name: Hallway Sensor

esp32:
  board: esp32dev

logger:
api:
  encryption:
    key: "your-key"
ota:
  platform: esphome

# PIR Motion Sensor
binary_sensor:
  - platform: gpio
    pin: GPIO5
    name: "Hallway Motion"
    device_class: motion
    filters:
      - delayed_off: 10s  # Keep "on" for 10 sec after motion

# Optional: Status LED
light:
  - platform: status_led
    name: "Status LED"
    pin: GPIO2

wifi:
  ssid: "your-wifi"
  password: "your-password"

📤 Upload and Test

Click INSTALL → Wirelessly (or USB first time)
Go to Home Assistant → Developer Tools → States
Search for binary_sensor.hallway_motion
Walk past the sensor - status changes to on

🔧 Adjust PIR Sensor

HC-SR501 has two small screws you can adjust:

┌─────────────────────────┐
│                         │
│   [Time]     [Sens]     │
│     ↑          ↑        │
│   Duration  Sensitivity │
│                         │
└─────────────────────────┘

Screw	Counter-clockwise	Clockwise
Time	Shorter “on” time (~3s)	Longer “on” time (~5min)
Sensitivity	Shorter range (~3m)	Longer range (~7m)

🤖 Automation: Turn on Light on Motion

Simple Automation

automation:
  - alias: "Turn on hallway light on motion"
    trigger:
      - platform: state
        entity_id: binary_sensor.hallway_motion
        to: "on"
    action:
      - service: light.turn_on
        target:
          entity_id: light.hallway

Advanced: Only at Night

automation:
  - alias: "Turn on hallway light at night"
    trigger:
      - platform: state
        entity_id: binary_sensor.hallway_motion
        to: "on"
    condition:
      - condition: sun
        after: sunset
        before: sunrise
    action:
      - service: light.turn_on
        target:
          entity_id: light.hallway
        data:
          brightness_pct: 50
      - delay: "00:02:00"
      - service: light.turn_off
        target:
          entity_id: light.hallway

Smart: With Timeout and Dimming

automation:
  - alias: "Smart hallway light"
    mode: restart  # Restart timer on new motion
    trigger:
      - platform: state
        entity_id: binary_sensor.hallway_motion
        to: "on"
    action:
      - service: light.turn_on
        target:
          entity_id: light.hallway
        data:
          brightness_pct: "{{ 30 if is_state('sun.sun', 'below_horizon') else 80 }}"
      - wait_for_trigger:
          - platform: state
            entity_id: binary_sensor.hallway_motion
            to: "off"
            for: "00:02:00"
      - service: light.turn_off
        target:
          entity_id: light.hallway

🔧 Troubleshooting

💡 Project Ideas

Project	Description
Automatic light	Turn on lights in hallway on motion
Security alarm	Send notification when away
Activity log	Track when rooms are used
Smart heating	Heat only used rooms

🚀 Next Steps

🌡️ Temperature sensor

Combine with temperature for complete room sensor.

Build temperature sensor →

💡 LED Strip

Turn on LED strip on motion for ambient light.

Build LED strip →