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THIRDREALITY Smart Presence Sensor R2

Compiled by SmartHomeWorkflow Research · THIRDREALITY · Sensors & Detectors · ~$39.99 (thirdreality.com listed the Smart Presence Sensor R2 at $39.99 on 2026-08-14, and the same figure still shows as the regular price on 2026-09-18. It was not a discount: the 'compare at' price shown was the same as the selling price. Price at time of research, never a live price. ⚠ THE PRICE DOES NOT BUY ONE TODAY: on 2026-09-18 the maker's own store shows the sensor as 'Sold out'. Nothing on the page says the model is discontinued, so this reads as a stock gap rather than an end of sale — but it is the maker's own storefront, and it is the only place we have seen this sensor sold.)

⚠ Similar names, different products: Third Reality's sensor shelf carries several devices a shopper will read as interchangeable and which detect completely different things: this mmWave PRESENCE sensor (radar — sees a still person), a 'USB Motion Sensor' at $14.99 (PIR — sees movement only) and a 'Vibration Sensor' at $19.99. Presence and motion are the distinction that decides whether the bathroom light stays on while you are standing still. The 'R2' is the generation marker; the model string on the SKU is P1MSR1A1-1.

Compatibility

? Inconclusive means we researched that ecosystem and the evidence doesn’t settle it — the catch says why, and the sources are listed below. It is a statement about the available evidence, never a verdict on the product. A Setup Check researches your exact setup where the official sources don’t answer.

Protocols: ZIGBEE^[2][9]

Needs before it works: A Zigbee hub or coordinator is REQUIRED — the vendor states 'Requires a compatible Zigbee hub or coordinator' and names the platforms it supports: 'Home Assistant (ZHA or Zigbee2MQTT), SmartThings, Aeotec, Homey, Hubitat, and Echo devices with built-in Zigbee hubs'. There is no direct-to-phone or Wi-Fi mode.^[2][9]

What it can do^[5][9]

Listed capabilities are what we could establish from vendor documentation. An ability missing here is unestablished — not necessarily absent.

Subscription reality^[2][9]

✓ Works without a subscription: Yes.

Vendor account required: Not established — we have not sourced this yet.

No subscription, plan or fee appears anywhere in the vendor's copy. A Zigbee sensor has no vendor cloud in its path once a hub adopts it; any recurring cost belongs to the hub's ecosystem rather than to this device.

Maintenance reality^[2]

• Batteries: 3 × AA — expect roughly 36 months per set
• Works without the internet: Inconclusive — we read the vendor's own material and it does not answer this either way. It does not mean the product fails without the internet.
• The vendor quotes '3 AA batteries, up to 3 years in typical usage' — an unusually long claim for a radar sensor, and the reason this one can go where no outlet exists ('hallways, bathrooms, cabinets, storage rooms, and other areas where wired power is inconvenient'). Detection is 24 GHz mmWave radar with five sensitivity levels and a stated range of roughly 1 to 5 metres; the vendor says it detects 'through common non-metallic materials such as wood and glass' and stays stable 'across changes in light, temperature, and humidity'. ⚠ It also publishes its own false-positive limit rather than hiding it: 'Environment learning helps reduce false triggers from everyday background movement, such as airflow or slight curtain movement. Strong or repetitive motion, such as fans, may still trigger detection.' In the box: the sensor and three AA batteries.
• Security updates: THIRDREALITY publishes no security-update support date for this model. That is a gap in what the manufacturer has published, not evidence either way — some makers declare a support period and some say nothing at all.^[2][9]

The catch

Two things decide whether this $39.99 sensor is a bargain or a brick. First, it needs a Zigbee hub — no Wi-Fi, no direct phone pairing — and the vendor's list of what qualifies is specific: Home Assistant (ZHA or Zigbee2MQTT), SmartThings, Aeotec, Homey, Hubitat, or an Echo that has Zigbee built in. Second, it is a radar sensor and radar has a characteristic failure the vendor publishes rather than hides: 'Strong or repetitive motion, such as fans, may still trigger detection.' Point it at a ceiling fan and it will see a person forever. What you get for the money is genuinely useful — presence rather than motion, so a light stays on while you sit still, through a cabinet door or a pane of glass, on three AA batteries the vendor rates for up to three years.

Who it's for

A Home Assistant, SmartThings or Hubitat household adding presence detection to rooms where people sit still and PIR sensors turn the lights off on them — bathrooms, offices, reading chairs — and that can place it away from fans and airflow. It is not for anyone without a Zigbee hub, and not for an Apple Home household: unlike this brand's plug, the sensor's page names no Apple route at all.

Sources & method

Numbered sources below back the facts marked with the matching number above. This is a research profile: compiled from manufacturer documentation, certification registries, and published testing — we state facts, not verdicts, and we have not physically tested this unit. How we work →

Compatibility and lifecycle information reflects the last-verified date above and can change without notice (firmware updates, cloud-service changes, discontinuations). It is provided as-is, for information — verify with the manufacturer before purchasing. Spot an error? Tell us and we'll fix it. Full terms: Terms of Service.

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