ESP32 Relay Board with LD2450

I had a PIR movement sensor in the basement controlling the light, but it sucked pretty bad and I had an LD2450 mmWave sensor lying around. I also found the relay board relatively cheap and just combined both things in a compact(ish) case.

BOM

• The Relay board (AC90-250 variant)
• The LD2450 (select it and not a cable or so)
• Some short cables
• (A Serial to USB converter)

Preparation

Connect the LD2450 to the relay board. Use 5v as the power supply and choose any of the GPIO pins to connect with the RX and TX pins from the sensor. Soldering the serial header on also makes sense to flash the esp with ESPhome for initial setup.

The Case

Print the 2 parts how you want, but I'd recommend to face the vent holes up. The sensor can be slid into the lid.

Software

esphome:
  name: device_name
  friendly_name: DeviceName

esp32:
  board: esp32dev
  framework:
    type: arduino

# Enable logging
logger:

# Enable Home Assistant API
api:
  encryption:
    key: "SOMETHING"

ota:
  - platform: esphome
    password: "SOMETHING"

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

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "DeviceName Fallback Hotspot"
    password: "SOMETHING"

captive_portal:
    

uart:
  - baud_rate: 256000
    rx_pin: GPIO32 # Adjust these pins (RX on ESP to TX on sensor)
    tx_pin: GPIO25 # Adjust these pins (TX on ESP to RX on sensor)
    parity: NONE
    stop_bits: 1
ld2450:
  - id: radar
    throttle: 500ms
binary_sensor:
  - platform: ld2450
    ld2450_id: radar
    has_target:
      id: has_target
      name: Presence
    has_moving_target:
      name: Moving Target
    has_still_target:
      name: Still Target
  - platform: copy
    source_id: has_target
    id: light_on
    filters: 
      - delayed_off: 0s # Adjust here for off delay
    on_press: 
      then:
        - switch.turn_on: light_relay
    on_release: 
      then:
        - switch.turn_off: light_relay
switch:
  - platform: gpio
    pin: GPIO16
    name: "Light"
    id: light_relay
  - platform: ld2450
    ld2450_id: radar
    bluetooth:
      name: "Bluetooth"
    multi_target:
      name: Multi Target Tracking"
button:
  - platform: ld2450
    ld2450_id: radar
    factory_reset:
      name: "LD2450 Factory Reset"
      entity_category: "config"
    restart:
      name: "LD2450 Restart"
      entity_category: "config"
text_sensor:
  - platform: ld2450
    ld2450_id: radar
    version:
      name: "LD2450 Firmware"
    mac_address:
      name: "LD2450 BT MAC"
    target_1:
      direction:
        name: "Target-1 Direction"
    target_2:
      direction:
        name: "Target-2 Direction"
    target_3:
      direction:
        name: "Target-3 Direction"
sensor:
  - platform: ld2450
    ld2450_id: radar
    target_count:
      name: Presence Target Count
  - platform: ld2450
    ld2450_id: radar
    still_target_count:
      name: Still Target Count
  - platform: ld2450
    ld2450_id: radar
    moving_target_count:
      name: Moving Target Count
  - platform: ld2450
    ld2450_id: radar
    target_1:
      x:
        name: Target-1 X
      y:
        name: Target-1 Y
      speed:
        name: Target-1 Speed
      angle:
        name: Target-1 Angle
      distance:
        name: Target-1 Distance
      resolution:
        name: Target-1 Resolution