Presence (+Light) Sensor Case - ESP32-C3 SuperMini

Meet the ultimate guardian of light and presence: a compact, screw-free 3D-printed case housing a presence sensor that’s basically a tiny overachiever. Powered by an LD2450 and a BH1750, it keeps a vigilant eye on motion and light intensity like a miniature security guard who never sleeps.

At its core, the ESP32-C3 Supermini handles all the smarts—like a tiny wizard running ESPhome spells—without breaking a sweat. The whole setup is snug, sleek, and doesn’t need screws (because who has time for tiny hardware battles?). Just plug it in, let it live its best life, and enjoy a sensor that’s as compact as it is clever.

Warning: may cause sudden urges to automate everything in sight.

Features:

• Tiny but Mighty: Leverages the ESP32-C Supermini – soldering skills required!
• Presence Detection via 24Ghz Radar (not only distance, but also position and speed)
• Light intensity measurement
• ESPHome Powered: Can be integrated into homeassistant.
• Compact Design: 55mm x 38.8mm x 11mm

Parts list:

• ESP32-C Supermini (can be found on Aliexpress for example)
• LD2450 (and optional wires with connector - all can be found on Aliexpress for example)
• BH1750 ((can be found on Aliexpress for example))
• 4 small pieces of wire and 2 small pieces of heat-shrink tubing
• Double sided Tape (something like Tesa Nanotape worked for me)
• Ball joint mount e.g. this

Equipment:

•  soldering iron

Soldering:

My ESPHome config:

esphome:
 name: wohnzimmer-presence
 friendly_name: wohnzimmer_presence

esp32:
 variant: ESP32C3
 board: esp32-c3-devkitm-1
 framework:
   type: esp-idf

# Enable logging
logger:

# Enable Home Assistant API
api:
 encryption:
   key: "whoopsdeletedit^^"

ota:
 - platform: esphome
   password: "whoopsdeletedit^^"

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

 # Enable fallback hotspot (captive portal) in case wifi connection fails
 ap:
   ssid: "Wohnzimmer-Presence"
   password: "whoopsdeletedit^^"

captive_portal:

uart:
 id: uart_bus
 tx_pin: GPIO21
 rx_pin: GPIO20
 baud_rate: 256000

i2c:
 id: i2c_bus
 sda: GPIO01
 scl: GPIO00
 scan: true

interval:
 - interval: 2s
   then:
     - switch.toggle: led
     - logger.log: "LED toggling"

ld2450:
 id: ld2450_radar
 uart_id: uart_bus

switch:
 - platform: gpio
   pin:
     number: 8
     mode: output
   id: led
 - platform: ld2450
   ld2450_id: ld2450_radar
   bluetooth:
     name: "Bluetooth"
   multi_target:
     name: "Multi Target Tracking"

number:
 - platform: ld2450
   ld2450_id: ld2450_radar
   presence_timeout:
     name: "Timeout"
   zone_1:
     x1:
       name: Zone-1 X1
     y1:
       name: Zone-1 Y1
     x2:
       name: Zone-1 X2
     y2:
       name: Zone-1 Y2
   zone_2:
     x1:
       name: Zone-2 X1
     y1:
       name: Zone-2 Y1
     x2:
       name: Zone-2 X2
     y2:
       name: Zone-2 Y2
   zone_3:
     x1:
       name: Zone-3 X1
     y1:
       name: Zone-3 Y1
     x2:
       name: Zone-3 X2
     y2:
       name: Zone-3 Y2

sensor:
 - platform: bh1750
   name: "BH1750 Illuminance"
   address: 0x23
   update_interval: 10s
 - platform: ld2450
   ld2450_id: ld2450_radar
   target_count:
     name: Presence Target Count
 - platform: ld2450
   ld2450_id: ld2450_radar
   still_target_count:
     name: Still Target Count
 - platform: ld2450
   ld2450_id: ld2450_radar
   moving_target_count:
     name: Moving Target Count
 - platform: ld2450
   ld2450_id: ld2450_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
   target_2:
     x:
       name: Target-2 X
     y:
       name: Target-2 Y
     speed:
       name: Target-2 Speed
     angle:
       name: Target-2 Angle
     distance:
       name: Target-2 Distance
     resolution:
       name: Target-2 Resolution
   target_3:
     x:
       name: Target-3 X
     y:
       name: Target-3 Y
     speed:
       name: Target-3 Speed
     angle:
       name: Target-3 Angle
     distance:
       name: Target-3 Distance
     resolution:
       name: Target-3 Resolution
   zone_1:
     target_count:
       name: Zone-1 All Target Count
     still_target_count:
       name: Zone-1 Still Target Count
     moving_target_count:
       name: Zone-1 Moving Target Count
   zone_2:
     target_count:
       name: Zone-2 All Target Count
     still_target_count:
       name: Zone-2 Still Target Count
     moving_target_count:
       name: Zone-2 Moving Target Count
   zone_3:
     target_count:
       name: Zone-3 All Target Count
     still_target_count:
       name: Zone-3 Still Target Count
     moving_target_count:
       name: Zone-3 Moving Target Count