LD2410 mmWave Presence Sensor with ESPHome

Medium 45 min

LD2410 is a mmWave radar sensor that can detect human presence - even when you’re sitting completely still. Perfect for bathroom, office or other rooms where PIR sensors fail.

🤔 Why mmWave over PIR?

Feature	PIR Sensor	mmWave (LD2410)
Movement	✅ Yes	✅ Yes
Stationary person	❌ No	✅ Yes (detects breathing)
Through glass/plastic	❌ No	✅ Yes
Distance measurement	❌ No	✅ Yes
False positives	Many	Few (with tuning)
Price	~$3	~$7

Perfect for bathroom

PIR sensors turn off the light while you’re sitting on the toilet. mmWave detects your breathing and keeps the light on!

📦 What You Need

Hardware

Component	Model	Price
mmWave sensor	HiLink LD2410C (recommended)	$5-8
Microcontroller	ESP32 or ESP8266 (D1 Mini)	$4-7
Wires	Dupont jumper wires	$2
USB cable	Micro USB for power	$3
Enclosure	3D printed or bought	$0-7
Total		~$15-30

LD2410 Versions

Model	Pins	Bluetooth	Recommendation
LD2410	1.25mm (needs adapter)	No	⚠️ Hard to solder
LD2410B	1.25mm (needs adapter)	Yes	⚠️ Hard to solder
LD2410C	2.54mm standard	Yes	✅ Recommended

Choose LD2410C!

LD2410C has standard 2.54mm pins that fit directly to Dupont wires. Other versions require special adapters or soldering.

⚡ Wiring Diagram

ESP8266 (D1 Mini) to LD2410C

D1 Mini         LD2410C
───────         ───────
3.3V    ───────  VCC
GND     ───────  GND
D7 (RX) ───────  TX
D8 (TX) ───────  RX

RX and TX cross!

Remember that RX on ESP connects to TX on LD2410 and vice versa. That’s how serial communication works.

🔧 ESPHome Configuration

Basic Setup

substitutions:
  device_name: "ld2410-bathroom"
  friendly_name: "Bathroom Presence"

esphome:
  name: ${device_name}
  friendly_name: ${friendly_name}

esp32:
  board: esp32dev

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

logger:
  baud_rate: 0  # Important! Disable serial logging

api:
  encryption:
    key: !secret api_encryption_key

ota:
  platform: esphome
  password: !secret ota_password

# UART for LD2410
uart:
  id: ld2410_uart
  tx_pin: GPIO17
  rx_pin: GPIO16
  baud_rate: 256000
  parity: NONE
  stop_bits: 1

# LD2410 sensor
ld2410:
  id: ld2410_sensor
  uart_id: ld2410_uart

Binary Sensors (Presence)

binary_sensor:
  - platform: ld2410
    has_target:
      name: "${friendly_name} Presence"
      device_class: occupancy

    has_moving_target:
      name: "${friendly_name} Movement"
      device_class: motion

    has_still_target:
      name: "${friendly_name} Stationary"
      device_class: occupancy

Distance Sensors

sensor:
  - platform: ld2410
    moving_distance:
      name: "${friendly_name} Moving Distance"
      unit_of_measurement: "cm"

    still_distance:
      name: "${friendly_name} Still Distance"
      unit_of_measurement: "cm"

    detection_distance:
      name: "${friendly_name} Detection Distance"
      unit_of_measurement: "cm"

    moving_energy:
      name: "${friendly_name} Moving Energy"

    still_energy:
      name: "${friendly_name} Still Energy"

📊 Complete Configuration

Here’s the complete configuration ready to copy-paste:

substitutions:
  device_name: "bathroom-presence"
  friendly_name: "Bathroom"

esphome:
  name: ${device_name}
  friendly_name: ${friendly_name}

esp32:
  board: esp32dev

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  ap:
    ssid: "${device_name}-AP"
    password: "12345678"

captive_portal:

logger:
  baud_rate: 0

api:
  encryption:
    key: !secret api_encryption_key

ota:
  platform: esphome
  password: !secret ota_password

uart:
  id: ld2410_uart
  tx_pin: GPIO17
  rx_pin: GPIO16
  baud_rate: 256000
  parity: NONE
  stop_bits: 1

ld2410:
  id: ld2410_sensor
  uart_id: ld2410_uart
  timeout: 5s
  max_move_distance: 3m
  max_still_distance: 2.25m

binary_sensor:
  - platform: ld2410
    has_target:
      name: "${friendly_name} Presence"
      device_class: occupancy
    has_moving_target:
      name: "${friendly_name} Movement"
      device_class: motion
    has_still_target:
      name: "${friendly_name} Stationary"
      device_class: occupancy

sensor:
  - platform: ld2410
    detection_distance:
      name: "${friendly_name} Distance"
    moving_energy:
      name: "${friendly_name} Moving Energy"
      internal: true
    still_energy:
      name: "${friendly_name} Still Energy"
      internal: true

  - platform: wifi_signal
    name: "${friendly_name} WiFi Signal"
    update_interval: 60s

switch:
  - platform: ld2410
    engineering_mode:
      name: "${friendly_name} Engineering Mode"
      internal: true

button:
  - platform: restart
    name: "${friendly_name} Restart"

🎯 Calibration

Step 1: Enable Engineering Mode

1. In Home Assistant, find your LD2410 device
2. Enable the Engineering Mode switch
3. Now you can see energy values for each gate

Step 2: Adjust Thresholds

Rule of thumb:

• Move threshold: Set 10-20 above what you see when room is empty
• Still threshold: Set 5-10 above baseline
• Lower = more sensitive (more false positives)
• Higher = less sensitive (might miss presence)

🤖 Automations

Bathroom Light Automation

automation:
  - alias: "Bathroom light ON on presence"
    trigger:
      - platform: state
        entity_id: binary_sensor.bathroom_presence
        to: "on"
    action:
      - service: light.turn_on
        target:
          entity_id: light.bathroom

  - alias: "Bathroom light OFF when empty"
    trigger:
      - platform: state
        entity_id: binary_sensor.bathroom_presence
        to: "off"
        for:
          seconds: 30
    action:
      - service: light.turn_off
        target:
          entity_id: light.bathroom

🔧 Troubleshooting

No data from sensor?

1. Check that baud_rate: 256000 is set correctly
2. Check that logger: baud_rate: 0 is set (frees UART)
3. Verify RX/TX are crossed correctly
4. Try swapping RX and TX pins

Too many false positives?

• Avoid pointing sensor at windows (movement outside)
• Avoid metal/mirrors that reflect signal
• Raise threshold values
• Reduce max_distance to room size

📐 Placement Tips

Placement	Recommendation
Height	1.5-2m above floor
Angle	Point downward 15-30°
Avoid	Directly at windows/doors
Range	Max 6m effective range

🚀 Next Steps

🏠 Better Thermostat

Combine presence with intelligent heating control.

Set up Better Thermostat →

⚡ Automations

Create more automations based on presence.

Your first automation →