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Hardware

An Everything Presence Pro device is a small sensor cluster, not a single chip. It carries two different mmWave radars, a PIR (passive infrared) motion sensor, environmental sensors (illuminance, temperature, humidity, CO2), and a network interface. Everything Presence Pro Grid's reliability comes from using all of them together — no single sensor is enough on its own. This page covers what each one does and how they complement each other.

Motion — fast infrared motion sensor

A traditional PIR (passive infrared) motion sensor (Panasonic EKMC1603111) is mounted on the device as a low-latency trigger. It sees heat-signature movement and reacts faster than either mmWave radar.

  • Field of view: 102° azimuth × 92° pitch.
  • Detection segments: 92 (lens elements that divide the field of view into discrete sensing zones).
  • Detection range: up to 12 m.
  • Strength: sub-second latency on entry, and a wider field of view than either radar.
  • Weakness: triggers only on heat-signature movement; goes quiet within seconds of stillness.

The mmWave radars

The device carries two mmWave radars, each for a different job.

LD2450 — movement tracker

The LD2450 is the workhorse. It's a phase-coded mmWave radar that reports 2D coordinates for each of three moving targets it sees. Everything Presence Pro Grid uses those coordinates to drive zone detection and target-count entities.

  • Field of view: 120° azimuth × 35° pitch.
  • Tracking depth: up to 6 m.
  • Concurrent targets: up to 3.
  • Strength: multi-target tracking with real coordinates.
  • Weakness: loses people who are genuinely still (reading, sleeping) after a few seconds, because the tracking relies on frame-to-frame radar signal changes.

SEN0609 — static-presence radar

The SEN0609 is a DFRobot static-presence mmWave module that fills in where the LD2450 drops off. It reports binary presence only — "someone is here" or "not here" — with no coordinates.

  • Field of view: 100° azimuth × 40° pitch.
  • Range: up to 16 m.
  • Strength: catches still-but-breathing occupants (reading, sleeping, showering) that the LD2450 loses. Much longer range than the LD2450's tracking circle.
  • Weakness: no per-target information — just a single room-wide presence signal.

Environmental sensors

Three environmental sensors ride along with the presence sensors. They're independent of presence detection — they just report room state.

  • BH1750 — digital lux meter for illuminance. Enabled by default.
  • SHTC3 — temperature and humidity sensor. Both enabled by default.
  • SCD4x / SCD40 — CO2 sensor. Optional add-on — not included with the device. Fit it yourself following the installation guide. Disabled by default in Home Assistant; enable it from the device page once fitted.

Note

The device runs warm, and ceiling or upper-corner mounting puts it where heat collects. Temperature and humidity readings skew higher than actual room conditions — useful for trends and deltas, but not reliable for climate control.

LED and relay

The device has a front LED which can reflect device state (occupancy, CO2 level) or be driven directly from your own automations. It also has a solid state relay output which can be used to make the device a smart sensor in your alarm system.

See the hardware overview for relay wiring and ratings.

Connectivity

The two current firmware variants differ only in which network interface is active:

  • wifi-ble-co2 — Wi-Fi. Needs SSID and password at flash time.
  • ethernet-ble-co2 — Ethernet. Plug in, power up, and the device shows up on the LAN. Supports Power over Ethernet (PoE), so a single cable handles data and power.

Both variants also include Bluetooth LE. Home Assistant exposes each device as a Bluetooth proxy for nearby BLE devices (temperature tags, buttons, presence badges). If you've got BLE hardware scattered around the house, each Everything Presence Pro device effectively becomes another reception point.

How the sensors complement each other

Each sensor has a blind spot that at least one other covers:

  • Motion sees heat-signature movement with the lowest latency.
  • LD2450 sees movement with coordinates, inside 6 m.
  • SEN0609 sees stillness without coordinates, out to 16 m.
  • Environmental sensors report room state independently of presence.

Azimuth coverage — LD2450, SEN0609, Motion overlaid at the same scale.

Pitch coverage — LD2450, SEN0609, Motion overlaid at the same scale.

The Occupancy binary sensor you'll typically automate against in Home Assistant is the combined output of all the presence signals — not any one sensor alone. That's why the device is a cluster rather than just an LD2450 board: each sensor individually has failure modes that the others cover.

A concrete example: someone walks into a bedroom, climbs into bed, and stays still while reading. The motion sensor catches the entry in a fraction of a second. The LD2450 tracks them moving to the bed. When they settle in and stop moving, the LD2450 drops them — but the SEN0609 keeps the room marked as occupied, so the lights don't turn off. The BH1750 reports falling illuminance as the sun sets, which you can use to trigger a reading light; the SHTC3 reports the room's temperature and humidity for the thermostat.

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