sensor

ThirdReality Door Sensor

budget local: excellent Zigbee

Price: $17.99 verified Nov 2, 2026
HA fit: good
Offline: yes
Setup: easy
Hub needed: yes

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ThirdReality Zigbee door and window sensor

Quick verdict

The ThirdReality Door Sensor is a straightforward Zigbee contact sensor that prioritizes reliability and price over extras. For entry alerts, auto-lock routines, and occupancy logic, it gives Home Assistant users dependable open/close state updates without cloud dependence.

Standout: Low-cost Zigbee contact sensing that scales well across many doors and windows.

Notes last checked May 31, 2026.

Compatibility snapshot

Home Assistant good

Apple Home none

Google Home none

Alexa none

Works offline yes

Setup easy

Extra hub needed yes

Power battery

Local control facts

Home Assistant: zha integration, Local Polling (home-assistant.io, checked Oct 10, 2026)
Zigbee2MQTT: supported device, listed as Third Reality 3RDS17BZ (Door sensor) (zigbee2mqtt.io, checked Oct 10, 2026)

Why it stands out

extremely affordable and great for covering every door and window
reliable open/close detection with solid Zigbee support
long battery life on 2x AAA batteries (up to 2 years)

Reasons to hesitate

no temperature or lux sensor like some pricier alternatives
requires a Zigbee coordinator
plastic build feels cheap, though it holds up fine

Best for

blanketing your home with door and window sensors on a budget
Zigbee-based Home Assistant setups needing basic contact sensors

Avoid if

you want a multi-sensor (contact + temperature + lux) in one device
you have no Zigbee coordinator

Privacy and local-control notes

Runs locally over Zigbee with no required cloud account. Open/close telemetry can stay entirely on your local hub and automation server.

Home Assistant support: supported · integration path: ZHA / Zigbee2MQTT.

Buying reality check

Price notes: One of the best value picks in Zigbee contact sensors, especially when purchased in multi-packs.

Verified price reads: lowest seen $13.99, latest $17.99 on Nov 2, 2026.

Nov 2, 2026$17.99amazon
Oct 31, 2026$19.99amazon
Oct 24, 2026$19.99amazon
Oct 17, 2026$19.99amazon
Oct 10, 2026$19.99amazon
Oct 8, 2026$13.99amazon
Oct 7, 2026$13.99amazon
Oct 6, 2026$13.99amazon

Compare side by side: see sensor comparisons →

What changed for this product

Oct 10, 2026 · Brief

Black Friday smart home deals for Home Assistant: the prices to beat

Black Friday 2026 smart home deals for Home Assistant and local-control homes: the lowest price I've recorded for 100+ Zigbee, Z-Wave, Matter and Wi-Fi devices.

From the change log and the news briefs that name this product.

Verified against

The compatibility notes above have not been through the source audit yet. The manufacturer's page is here; the notes were last checked May 31, 2026.

Spotted something wrong? Report an error on this page and I will check it against the source and fix it.

Buying guide for this category

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Articles that mention this product

Black Friday smart home deals for Home Assistant: the prices to beat

Black Friday 2026 smart home deals for Home Assistant and local-control homes: the lowest price I've recorded for 100+ Zigbee, Z-Wave, Matter and Wi-Fi devices.

Read article →