Shelly's Presence Gen4 Counts Up to 10 People With Radar, No Camera Required

Shelly announced the Presence Gen4 this week, a mmWave radar presence sensor that can track up to 10 people moving through a room without a camera lens in sight. It went on sale for $84.99 at Shelly's online store, with Amazon, Best Buy, Micro Center, and Newegg to follow, according to CE Pro. The launch comes about a month after Shelly's $50 subscription-free security camera, and together the two products sketch the company's pitch clearly: the sensing smarts of a camera-heavy home, without the cameras and without the monthly fees.

The sensor uses millimeter-wave radar to detect micro-movements, including people sitting still, which is the classic failure of passive infrared motion sensors. A PIR sensor needs something to move across its field of view; sit on a sofa with a book for twenty minutes and the lights decide you left. Shelly says the Gen4 picks up the small movements of people, pets, and objects whether they are in motion or stationary, so automations react to actual presence rather than motion events.

Ten people, ten zones, one radar

The headline numbers are straightforward: up to 10 people tracked simultaneously, and up to 10 independently customizable detection zones that can each trigger their own automation. The lamp only turns on when someone actually sits at the desk; the home theater only powers up when someone settles onto the sofa. Wall-mounted, the sensor covers a 140-degree horizontal field across up to 650 square feet. Corner-mounted, it narrows to a 90-degree field covering up to 525 square feet. It can also sit on a shelf or table on its built-in stand.

Shelly includes a real-time occupancy map that shows where people are detected in a space, plus ready-made radar configurations through a presets menu for common room layouts. A built-in light sensor reports three ambient levels, dark, twilight, and bright, so light-aware automations can factor in whether the sun is already doing the job.

Tuning is where these sensors usually live or die. Adjustable minimum and maximum height thresholds let the Gen4 filter out pets, robot vacuums, and other low-to-the-ground objects, or restrict recognition to human-sized movement. Coverage notes you can choose to include small objects like pets, or dial the sensitivity so the automations ignore the robovac's nightly rounds instead of treating them like a home invasion.

The sensor knows the room is occupied without ever seeing it, and that distinction is the whole point.

No camera, and no cloud if you do not want one

The privacy argument writes itself: a radar blip is not a video feed. CE Pro calls it a more privacy-friendly option compared to video-based monitoring, and for bedrooms, hallways, and rental properties, that matters. A camera in the living room is a trust decision; a radar sensor is a configuration choice.

Shelly backs that up with architecture, not just marketing. The Gen4 supports cloud-free local control, so the sensor can run on the local network without phoning home, alongside custom scripting and an embedded web interface for direct management. That timing is notable: CE Pro points out that Anthropic recently warned the public about the potential for AI agents to unintentionally set up self-replicating botnets on home internet devices. Home IoT gear has a long history of being conscripted into botnets, and keeping the sensor off the cloud removes a whole class of attack surface.

The specs, and the fine print

Connectivity is the full Shelly Gen4 spread: Wi-Fi 6, Bluetooth 5 LE, Zigbee 3.0, and Matter over Wi-Fi, with native interoperability listed for Google Home, Amazon Alexa, Apple Home, Samsung SmartThings, and Home Assistant. Shelly's model number is S4SN-0U61X, and it ships in white and black finishes.

Power is the one constraint: this is not a battery device. The Gen4 needs a wired USB-C power source, and Shelly warns against multi-port or fast-charging adapters whose fluctuating output can damage the unit, recommending a dedicated high-quality 5V adapter instead. Placement still matters; Shelly's own documentation says to plan the mounting position carefully, since reflective surfaces can create false targets, a familiar caveat for mmWave gear that reviewers of Aqara's competing sensors have flagged as well.

At $84.99 it sits just above Aqara's FP400, the $79.99 spatial sensor with eight zones that smart-home buying guides have been comparing it against. Shelly's answer is broader protocol support, more people and more zones, and the local-control story the brand is known for. It is the kind of launch that does not pretend to reinvent the category. It just fixes the two complaints that have dogged presence sensing for years: the lights should not turn off while you are still in the room, and the device that watches the room should not need to watch you.

Installation deserves one more note: the Gen4 wants USB-C power and a thoughtful mounting spot, which makes it a weekend project rather than a stick-it-anywhere gadget. But that is also why Shelly's core audience, the local-control tinkerers who run Home Assistant and write custom scripts, will likely be the first buyers. For everyone else, the pitch is simpler than a wiring diagram: a sensor that keeps the lights on while you are home and knows nothing about what you look like.