Shelly Blu Motion Review: Tiny, Fast and Long-Lasting Bluetooth Sensor, but You Need Another Shelly to Bridge It
This ultra-compact Bluetooth motion and lux sensor responds almost instantly, runs for years on a battery and is highly configurable, but it requires another Shelly (or a BLU Gateway) to reach WiFi, isn't suited to outdoor use, and Shelly's instructions are sparse.
The Shelly Blu Motion is a tiny Bluetooth LE motion sensor with a built-in lux sensor, and owners rate it decently (a 3.9-star average). Its strengths: it's extremely compact (almost invisible once mounted), responds fast (often within 100ms to a few seconds), and is remarkably easy to set up, it ships already powered on (no pull tab), and Home Assistant auto-detects it via BTHome as long as you have another Shelly nearby acting as a Bluetooth-to-WiFi bridge. It's highly configurable (multiple sensitivity levels with pet filtering, adjustable timeout), has a long battery life (up to ~5 years on a CR2477), and includes a lux sensor so you can trigger lights only when it's dark. It integrates with Home Assistant, Alexa and Google, and owners praise the value, buying several. The main caveat is architectural: being Bluetooth, it needs another Shelly device (a Plus/Pro model or a Shelly BLU Gateway) to reach WiFi and the rest of your smart home, and to actually switch lights you'll want another Shelly (like a Shelly 1). It's also not suited to outdoor use, owners report very limited range and spurious triggering outside, even under eaves. As with battery sensors generally, the lux value only updates when motion is detected, Shelly's instructions are sparse (expect to read up to configure it), and the included adhesive doesn't hold on glossy surfaces. A few had Bluetooth connection trouble. For a Shelly household wanting a small, responsive, long-lasting indoor sensor, it's a strong value, provided you have the bridge.
- Existing Shelly households (with a Plus/Pro bridge)
- Home Assistant users (BTHome auto-detect)
- Tiny, discreet indoor motion sensing
- Fast, low-latency lighting automations
Pros
- Ultra-compact and discreet; fast, low-latency detection
- Very easy setup (ships powered on; Home Assistant BTHome auto-detect)
- Highly configurable (sensitivity levels, pet filter, timeout); built-in lux sensor
- Long battery life (up to ~5 years); strong value
Cons
- Requires another Shelly (Plus/Pro) or BLU Gateway to bridge Bluetooth to WiFi
- Not suited to outdoor use (limited range, spurious triggers)
- Lux value only updates on motion; sparse instructions
- Included adhesive doesn't hold on glossy surfaces; occasional Bluetooth connection issues
Who is the Shelly Blu Motion for?
This is an ultra-compact Bluetooth LE motion sensor with a built-in lux sensor, rated to about 9m/30ft range with a long battery life. Being Bluetooth, it requires another Shelly device (Plus/Pro) or a Shelly BLU Gateway to bridge it to WiFi, and it integrates with Home Assistant, Alexa and Google. It's ideal for people already using Shelly hardware, especially Home Assistant users, who want a small, fast, configurable indoor sensor for lighting automations. It's not for you if you have no Shelly bridge device, need outdoor use, or want a standalone sensor that connects directly to WiFi.
What buyers love
Ease and responsiveness lead. It arrives already powered on (no plastic tab to pull), and Home Assistant offers to add it automatically via BTHome the moment it's nearby, provided you have a Shelly device acting as a Bluetooth-to-WiFi bridge, so setup can be as simple as mount and go. It's very fast (owners cite responses from under 100ms to a few seconds), tiny and discreet, and highly configurable, with multiple sensitivity levels, pet filtering, and an adjustable timeout. The lux sensor enables dark-only lighting triggers, battery life is long (up to around five years), and owners repeatedly praise Shelly's value and reliability, buying multiples and integrating them with Shelly plugs and Home Assistant. It's a favorite for turning lights on by presence in kitchens, entries and living rooms.
What to know before you buy
The key thing to understand: it's Bluetooth-only, so it needs another Shelly device (a Plus/Pro model) or a Shelly BLU Gateway to bridge it to WiFi and the rest of your home, and to actually switch lights you'll want a Shelly relay (like a Shelly 1). If you don't already have Shelly hardware, factor that in. It's also not designed for outdoor use, owners who tried it under eaves report very limited range even at high sensitivity, plus spurious on/off triggering. As with any battery-powered motion sensor, the lux reading only updates when motion is detected (to save battery). Shelly's instructions are sparse, so expect to read up to configure it the way you want (once you do, it's very flexible). The included double-sided tape doesn't stick well to glossy trim, and a few owners had trouble getting it to connect over Bluetooth at all.
Is the Shelly Blu Motion worth it?
For a Shelly setup, yes. It's tiny, fast, long-lasting and highly configurable, with easy Home Assistant integration and strong value, which is why owners who have the bridge love it (and the 3.9-star average is dragged down partly by architecture confusion and outdoor attempts). Just plan around the requirements: you need another Shelly device or a BLU Gateway to bridge Bluetooth to WiFi, it's indoor-only, the lux updates only on motion, and Shelly's documentation is minimal. If you already run Shelly hardware and want a small, responsive indoor sensor for lighting automations, it's an excellent, affordable choice; if you have no Shelly bridge or need outdoor detection, look elsewhere.
Frequently asked questions
Can it work on its own without other Shelly devices?
No. It's Bluetooth-only, so it needs another Shelly device (a Plus/Pro model) or a Shelly BLU Gateway to bridge it to WiFi and your smart home. To actually control lights, you'll also want a Shelly relay like a Shelly 1. If you don't already own Shelly hardware, budget for a bridge device.
Is setup really that easy?
For Home Assistant users with a Shelly bridge nearby, yes. It ships already powered on (no tab to pull), and Home Assistant auto-detects it via BTHome, so you can mount it and it's ready. Note Shelly's written instructions are sparse, so more advanced configuration takes a little reading.
Can I use it outdoors?
It's not designed for outdoor use, and owners who tried it (even under eaves) report very limited detection range and spurious on/off triggering. For reliable outdoor motion sensing, choose a weatherproof sensor instead; the Blu Motion is best kept indoors.
How long does the battery last, and how does the lux sensor work?
Battery life is long, up to about five years on a CR2477. The built-in lux (light) sensor lets you trigger lights only when it's dark, but as with any battery-powered motion sensor, the lux value only updates when motion is detected, to conserve battery, rather than continuously.
Does it work with Home Assistant, Alexa and Google?
Yes. It integrates with Home Assistant (via BTHome, using a Shelly device as the Bluetooth bridge), as well as Alexa and Google. It's highly configurable in the Shelly app, with adjustable sensitivity (including pet filtering) and timeout, making it flexible once you have the bridge in place.









