Presence & mmWave

PIR died in 2024. mmWave radar is the 2026 differentiator that makes lights stay on while you read, automatically dim when you doze, and detect a person sleeping vs. an empty room. Cheap (~$10 sensors), accurate, and natively supported in ESPHome.

For the hub above this layer see Smart Home Hubs; for the firmware that wraps the radar see IoT Firmware Platforms; for BLE-based presence see BLE & Bluetooth IoT.

Why mmWave matters

• PIR (passive infrared) — sees motion only. You sit still on the couch → the lights turn off.
• mmWave radar (24 GHz / 60 GHz / 77 GHz) — sees micro-movements (breathing, heartbeat). You're there, even still → the lights stay on.
• 2026 sweet spot: an ESP32 + a $5-15 radar module + ESPHome; HA gets occupancy, often per-zone (with the LD2450 / FP2).

The cheap radars (ESPHome-friendly)

• ★ HiLink LD2410 / LD2410B / LD2410C — 24 GHz; presence + motion + distance; 5-6 m range. Single-target. The gateway drug. ~$8 / $10 with the BLE Bluetooth-config app. ESPHome native component.
• ★ HiLink LD2412 — newer; better through-wall rejection; same form factor.
• ★ HiLink LD2420 — 24 GHz; lower-priced; less mature than 2410.
• ★ HiLink LD2450 — 24 GHz; multi-target tracking with X/Y coordinates; up to 3 people; ~$15. The "I want zones" answer.
• HiLink LD1115H / LD1125H — earlier generations; mostly superseded.
• Seeed MR60BHA1 / MR60FDA1 — 60 GHz; breathing / heart-rate detection; pricier; ESPHome support.

Productized presence sensors

• ★ Aqara FP2 — Zigbee/Wi-Fi; multi-zone; up to 5 people; HomeKit + HA. The "buy this and stop fiddling" pick. ~$80.
• ★ Apollo Automation MS24 / MSR-2 — ESPHome-based; combines mmWave + voice satellite + air-quality sensors + ambient light + temp/humidity. The all-in-one room sensor. ~$80.
• Apollo MTR / Apollo PLT-1B — bare mmWave plus presence; cheaper Apollo SKUs.
• Everything Smart Tech (EST) presence sensor — small US shop; ESPHome firmware; Zooz partnership.
• EspressIF ESP32-S3-BOX-3 — has a radar in some variants; not its main role but works.
• GL.iNet "Presence Sensor" — newer entrant; verify firmware openness.

Productized presence sensors (Zigbee)

• ★ Aqara Presence Sensor FP1 / FP1E / FP2 — Zigbee or Wi-Fi; multi-zone (FP2); the polished commercial pick.
• Tuya mmWave sensors — many models; flashable to ESPHome via LibreTiny if Tuya cloud's a no-go.

DIY pattern

Standard 2026 ESPHome presence sensor:

1. ESP32-C3 / C6 ($3) + LD2410 ($8) + 5 V → 3.3 V regulator + USB-C.
2. ESPHome ld2410 / ld2412 / ld2450 component → Bluetooth or web config.
3. Mount in a 3D-printed case in the room corner / ceiling.
4. ~$15 per room, ~30 min to set up after the first one.

Repos with proven configs:

• ★ EverythingSmartTech ESPHome configs — open YAML repo.
• ESPHome's docs ld2410.html — official.

Presence detection (BLE-based, complementary)

• ★ ESPresense — ESP32 firmware that uses BLE RSSI from your phone / wearables / iBeacons → room-level presence. Less accurate than mmWave for "is the room occupied" but answers "where am I in the house" with one ESP32 per room.
• See BLE & Bluetooth IoT for more on BLE proxies / gateways.

Sensor fusion (the 2026 best practice)

For a bedroom: mmWave (room occupancy) + bed sensor (a load cell or contact sensor under the mattress) + lux sensor + CO2 = an HA template that knows whether you're awake-in-bed, asleep, or out of the room. The new generation of HA users does this routinely.

Frameworks / blueprints:

• ★ HA Adaptive Lighting + Mushroom dashboard — the surface area on top.
• home-assistant/blueprints "Bedtime detector" — community starter blueprint.

Practical guidance

• ★ Mount mmWave at human-torso height (1.0-1.5 m), not ceiling. Most chips are tuned for chest detection; ceiling mounts are weaker.
• ★ Sweep a fan in front of an LD2410 to test — moving fan blades trigger motion; useful to isolate "is the sensor live."
• Glass and thin drywall don't block 24 GHz. Your bedroom sensor will hear the hallway. Tune sensitivity.
• Avoid metal ducts behind the sensor. Reflections create phantom targets.
• Don't expect mmWave to replace doorbells / leak sensors / switches. It's an occupancy sensor; ask it occupancy questions.
• Pair with PIR for redundancy in critical automations (e.g., security). PIR has fewer false-positives for the "is anyone moving?" question.

Pick this if…

• Cheapest possible presence: ESP32 + LD2410 (DIY).
• Multi-zone room: LD2450 (DIY) or Aqara FP2 (productized).
• All-in-one with voice + AQ: Apollo MS24.
• Plug-and-play, no DIY: Aqara FP2.
• Where-am-I-in-the-house presence: ESPresense.