Short answer: PIR sensors detect moving heat signatures and suit simple on/off lighting control in corridors, entryways and storage areas at $2-8 per unit FOB. mmWave radar sensors detect micro-movements such as breathing, keeping lights on for seated or sleeping occupants — the right choice for offices, hotel rooms and bathrooms at $10-40. Most B2B buyers now stock both, matched to each room type.
1. How Each Technology Actually Works
| PIR (Passive Infrared) | mmWave Radar | |
|---|---|---|
| Principle | Pyroelectric element behind a Fresnel lens registers changes in infrared heat as a warm body crosses detection zones | 24GHz or 60GHz radio waves bounce off objects; the chip analyzes micro-Doppler shifts from movement down to breathing |
| Detects still person | No — times out after the set delay (30s-10min typical) | Yes — breathing-level motion is enough |
| Typical range | 3-7m (up to 12m on ceiling-mount long-range models) | 4-10m, with configurable distance gating on better firmware |
| Field of view | 90-120° (lens dependent) | 90-120° horizontal, narrower vertical |
| Power draw | Microamps — 2-3 years on a CR2450 or 2×AAA | Milliwatts — usually mains-powered; low-power chips allow ~6-12 months battery |
| Factory price band | $2-8 FOB | $10-40 FOB |
2. Where Each One Fails — The Return-Rate Drivers
PIR failure modes: the occupant sits still and lights cut out (the classic office complaint); false triggers from radiators, direct sunlight on the lens, HVAC airflow and large pets; detection dead zones directly below a ceiling unit. mmWave failure modes: false triggers from fans, swaying curtains and plants; partial penetration through glass and thin partitions causing triggers from adjacent rooms; sensitivity drift if firmware lacks zone configuration. A credible supplier tests both and ships firmware with adjustable sensitivity, distance gating and lux threshold — not a fixed-threshold board.
3. Room-Type Selection Matrix
| Space | Recommended | Why |
|---|---|---|
| Corridor, entryway, stairwell | PIR | People always moving; lowest cost per point; battery retrofit friendly |
| Office workstation, meeting room | mmWave | Seated occupants; PIR timeout complaints kill projects here |
| Hotel guest room / bathroom | mmWave (dual-tech ideal) | Shower and reading-in-bed presence; see our hotel smart lighting solution |
| Warehouse, storage | PIR long-range ceiling | 12m range models cover aisles cheaply |
| Bedroom night-light path | PIR + low-level strip | Motion is enough; mmWave overkill and mains wiring awkward |
4. 24GHz vs 60GHz mmWave
24GHz radar modules are the cost-effective mainstream: proven supply chain, adequate for room-scale presence at $10-20. 60GHz offers finer resolution (sub-meter zoning, more accurate still detection at longer range) and a cleaner regulatory path in some markets, at $20-40. For a distributor assortment, 24GHz covers 80% of projects; spec 60GHz for premium office and healthcare jobs where detection accuracy justifies the delta.
5. Specs To Put In Your RFQ
- Detection range and angle at stated mounting height (2.4-3m ceiling typical) — demand test data, not brochure numbers;
- Still-person hold time — mmWave units should hold presence indefinitely, not recycle every few minutes;
- Adjustability — sensitivity, distance gating, lux threshold and off-delay configurable in app, not fixed at factory;
- Protocol — Tuya Zigbee 3.0 or BLE Mesh for ecosystem projects (compare options in our PLC vs Zigbee vs BLE Mesh guide), Matter bridge path in writing;
- Power — battery chemistry and claimed life under real trigger rates, or mains voltage range 100-240V AC;
- False-trigger immunity — pet immunity for PIR (under 25kg typical), fan/curtain filtering for radar;
- IP rating — IP20 indoor default, IP44+ for bathroom zones;
- Certifications — CE-RED for the radio, RoHS, FCC for US-bound SKU; radar band approval varies by market.
6. The 8-Point Sourcing Checklist
- Seated-person test — sample must hold detection on a person reading for 10+ minutes (mmWave) before you discuss price;
- Firmware access — confirm sensitivity/zones adjustable in the Tuya app or vendor app, with OTA update policy;
- False-trigger soak test — run samples 72 hours against fans, curtains and HVAC; log triggers;
- Same-family pairing — sensors, smart switches and drivers from one panel family so installers mix freely;
- Real factory — own SMT line and burn-in racks; verify per our factory verification guide;
- MOQ reality — branding from 100-300 pcs/SKU; below 100 usually means a trader;
- Lead time in writing — samples 3-7 days, mass production 25-35 days;
- After-sales — 2-3 year warranty, 1-2% free spares, DOA replacement terms in the contract.
7. FAQ
Can mmWave presence sensors detect someone sitting still?
Yes — that is their core advantage. 24GHz/60GHz radar picks up breathing-level micro-motion, so lights stay on for a person reading or working at a desk. PIR only registers larger movements and typically times out within 1-10 minutes of stillness — the number-one complaint in office and bathroom projects.
Can mmWave radar see through walls?
Partially through glass, thin wood and plasterboard; blocked by concrete, brick and metal. In practice a radar sensor can false-trigger from movement behind a thin partition — solve it with sensitivity zoning and distance gating, and test on site before mass rollout.
Are there battery-powered mmWave presence sensors?
They exist but compromise: radar draws far more power than a passive PIR element, so most presence sensors are mains-powered. New low-power chips enable battery mmWave units with ~6-12 months of life versus 2-3 years for PIR on a CR2450. Battery-only retrofit stays PIR territory; true presence detection needs a mains feed.
What is the factory-level price difference?
Tuya Zigbee PIR motion sensors land around $2-8 FOB; mmWave presence sensors run $10-40 depending on band (24GHz vs 60GHz), power design and firmware features. Dual-tech models sit in between. A mixed assortment — PIR for volume corridors, mmWave for premium rooms — cuts return rates versus a one-technology lineup.
This article was contributed by SSW Lighting (Shanghai Shiwei Intelligent Technology Co., Ltd.), a smart lighting OEM/ODM manufacturer serving distributors and project contractors in 30+ countries. Explore the sensor and lighting product line, review our manufacturing capabilities, or check project cases. For samples and a quotation: info@shenshiwei.com · +86-21-58979139 · www.shenshiwei.com.
← Back to news