Radar Tech Reinvents Smart Doorbells for Designers
New Tech Tuesdays
Join Mouser's Technical Content team for a weekly look at all things interesting, new, and noteworthy for design engineers.
Published December 2, 2025
Smart doorbells are learning a new trick: seeing without cameras. Rather than relying on cameras and motion sensors, new designs and research projects are incorporating compact mmWave radar chips that can detect when someone is standing still at the door, waving, or even breathing. Since they work by reading radio wave reflections instead of recording videos, they can detect in the dark and rain without recording an image.
As a result of recent improvements in radar design, there are now compact, low-power sensors that can fit easily into consumer devices. In a smart doorbell, the technology can sense if someone is approaching, differentiate between a person and a passing car, and operate in harsh and dark conditions (Figure 1).
Figure 1: Even with porch lights on, standard cameras can struggle to capture clear details at night, missing quick movements like passing cars or people outside the frame. (Source: EFA/stock.adobe.com; generated with AI)
In this week’s New Tech Tuesdays, we look at how these radar capabilities are already appearing in products today, as well as how future designs are adding more detailed gesture input and even the ability to identify recurring visitors without a camera.
Why Radar for Smart Doorbells?
The sensors integrated into most doorbells, such as cameras, passive infrared (PIR) detectors, and microphones, all come with their own weaknesses. PIR sensors can miss slow or subtle motions and be fooled by small animals or trees, while cameras cannot always see in certain lighting, making privacy a frequent concern.
Radar helps overcome these weaknesses by emitting high-frequency radio waves and analyzing the reflected signals to determine an object’s distance, speed, and even small motions. As a result, it can detect someone standing still, differentiate between a person and an animal, and monitor vital signs without contact.
Radar in Consumer Devices Today (And Soon)
Radar is already shipping in consumer products and moving into more categories. For example, the Aqara G410 Smart Doorbell uses mmWave radar to enhance presence detection and reduce false alerts caused by passing cars, pets, or blowing leaves.[1] It still includes a camera but adds radar as a second layer, combining on-device facial recognition, Matter support, and hub functionality into one system.
Researchers are also making headway with radar. With RaGeoSense, mmWave point cloud data can be used to read hand movements, making it possible to trigger a doorbell or open a lock with just a wave.[2] GesturePrint builds on that concept by using those same radar readings to identify specific people based on how they move, with reports indicating a 98 percent accuracy rate.[3] This could allow doorbells to confirm familiar users and still keep privacy intact.
How It Works
Modern mmWave radar modules combine transmitters, receivers, antennas, and signal processing in compact, power-efficient units. The sensor emits radio waves that reflect off objects in its detection zone. By analyzing the timing, frequency shift, and amplitude of the reflected signals, the system can determine how fast and how far away an object is, as well as detect micro-movements like breathing.
When this technology is integrated into a doorbell, radar data is processed locally by a microcontroller or system-on-chip using classification algorithms. These algorithms make it possible to separate relevant and irrelevant activity, filter out false triggers, and enable more advanced features such as gesture recognition or occupancy-based automation.
Integrating radar enables designers to balance power use, handle RF-sensitive layouts, and process raw data in real time.
The Newest Products for Your Newest Designs®
The Texas Instruments IWRL6432FSPEVM sensor evaluation module (EVM) is an ideal fit for radar-enabled smart doorbells because it combines a compact 60GHz mmWave radar sensor with onboard processing, low power consumption, and a wide field of view. This allows designers to achieve highly accurate presence and motion detection—even in darkness, rain, or through obstructions—while filtering out irrelevant movement, such as pets or passing cars. Its integrated hardware accelerators and Arm® Cortex®-M4F core enable real-time gesture recognition and micro-motion sensing without requiring heavy external computation, supporting privacy-focused features like camera-free operation and user-specific recognition.
Tuesday’s Takeaway
Radar is moving beyond automotive and industrial systems and into everyday smart home devices. For smart doorbells, it delivers precise detection that works in any lighting, rain or shine, and cuts down on false alerts, all while creating new user experiences like gesture control. With research advancing toward user-specific recognition and more micro-motion detection, designers have the opportunity to reinvent the doorbell as a multifunctional entryway device, rather than just a single-purpose alert system.
Sources
[1]https://us.aqara.com/products/aqara-video-doorbell-g410
[2]https://www.nature.com/articles/s41598-025-00065-8
[3]https://arxiv.org/abs/2408.05358