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The Useful Sensors Person Sensor is a compact, pre-programmed face-detection module that sends presence and face-position data to a separate controller over I2C. Pair it with an Arduino, Raspberry Pi Pico, Raspberry Pi, or another supported host, then use the host to wake a display, mute a microphone, steer a fan, or trigger another action.
What the Useful Sensors Person Sensor does
The module combines an image sensor with a small microcontroller. Its internal implementation is abstracted behind a standard I2C interface, so a maker can read detection data without building a camera-processing system from scratch. Useful Sensors says it can report how many people are present and where they are relative to the device; the documentation also describes facing, identity, and confidence information. See the official developer guide.
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It is an input device, not a standalone computer: the Person Sensor supplies structured data, while a host controller decides what that data should do and drives an output such as a screen, servo, LED, relay, or network module.
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1Fix the driver behind crashes, sound loss and screen glitches2Repair Windows errors before they cause bigger problems3Scan for outdated or missing drivers - takes under a minuteWhat you need for a typical build
- A Useful Sensors Person Sensor.
- A Qwiic-compatible I2C cable or a suitable I2C connection to your host.
- A host controller and its supported programming environment.
- An output device, if the project needs to act on detection data—for example, a display, LED, servo, relay, or network module.
A typical arrangement is Person Sensor → I2C/Qwiic cable → host controller → output. Check the host and sensor documentation for the correct wiring and power requirements for your particular board; the sources do not establish one universal wiring or power setup for every host.
#1 Best Overall
- ACCURATE PEOPLE COUNTER SENSOR: Infrared beam technology registers a visitor only when the beam is physically interrupted — over 98% accuracy with minimal false counts from lighting changes, air movement, or shadows. A reliable foot traffic counter for retail doors and entrances.
- WIRELESS & BATTERY OPERATED: Fully wireless door counter powered by 4 AAA batteries for up to 12 months of continuous use — no Wi-Fi, no app, no wiring or calibration. Read the live visitor count directly on the built-in display.
- TOOL-FREE INSTALL IN MINUTES: Mount the transmitter and receiver opposite each other with adhesive tape or screws and start counting right away. An effortless customer counter for any store, office, or business entrance.
- PROTECTED RESET CONTROL: The count resets only with the included magnetic key, preventing accidental or unauthorized resets and keeping your people counting data accurate in busy retail environments.
- BUILT FOR RETAIL & BUSINESS: A versatile door counter for stores, boutiques, museums, libraries, galleries, and offices. Track customer traffic, staff smarter, measure conversion, and flag off-hours security anomalies. Color: Grey.
Choosing a host controller
The official guide provides examples for Arduino, CircuitPython, Raspberry Pi Pico, Raspberry Pi, and Micro:bit. Choose based on your programming preference, available I/O, connectivity, power needs, and the size of the enclosure—not on the sensor alone.
| Host option | Documented software or example support | Useful when |
|---|---|---|
| Arduino | Arduino examples; the product is also identified as usable with Arduino IDE and C/C++ via I2C Qwiic by Make:’s December 20, 2024 review. | You want a microcontroller-based build and need to connect outputs such as LEDs, relays, or servos. |
| Raspberry Pi Pico | Official Raspberry Pi Pico examples. | You want a compact microcontroller host; check the exact board’s I2C wiring and available I/O for your project. |
| Raspberry Pi | Official Raspberry Pi examples. | Your project benefits from a small computer and its broader software or connectivity options. |
| Micro:bit | Official Micro:bit examples. | You want to build around a supported educational or prototyping board. |
| CircuitPython | Listed as supported by Make:’s December 20, 2024 review; see the official guide for examples. | You prefer a Python-style workflow on a compatible microcontroller board. |
The official examples and project links are collected in the Useful Sensors developer guide. Make:’s review lists Arduino IDE, Python, CircuitPython, and C/C++ support through an I2C Qwiic connection; those descriptions should not be read as a guarantee that every language runs on every host board.
Rank #2
- ACCURATE: More sensors = More accuracy. Conventional electronic stud finders have 1 or 2 sensors. The ProSensor 710+ has 13, making it the best stud finder on the market
- EASY: No calibration is required. Simply press and hold the button to begin scanning. Unlike other wall stud finders that give false readings, the ProSensor 710+ lets you start scanning anywhere, even over a stud
- SHOWS FULL WIDTH OF STUDS: Unlike magnetic stud finders that only find screws, the ProSensor 710+ detects the full width of studs. The LED display shows the whole stud and double studs, and the middle LED will turn green to indicate stud centers
- DEEP SCAN ALWAYS ON: One mode finds it all! The ProSensor 710+ stud finder for drywall has deep detection up to 1.6 in and finds both wood and metal studs
- EXTRA FEATURES: The 710+ stud finder includes a built-in bubble level and integrated ruler. Requires batteries, not included. NOT compatible with rechargeable batteries
Maker projects to build
Wake a kiosk or interactive display
Use a presence or face-detection result as the trigger for a host to wake a screen or start an interactive display. The sensor detects; the host handles the display’s power or software state. Useful Sensors gives a kiosk display as an example use case.
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A host can use detected presence to control a microphone mute state or an indicator showing whether the microphone is enabled. This is a privacy-oriented project idea, not a guarantee that the sensor can identify every person or every absence in all conditions.
Rank #3
- INFRARED TECHNOLOGY: The visitor counter uses infrared ray interruption technology, which provides accuracy over 98% and stability in case of minor changes in lighting conditions
- WIRELESS: The visitors counter works with batteries that can be bought anywhere
- PLUG & PLAY: The people counter is installed using supplied sticky plates or special holes in the device body
- POWERED BY BATTERIES. People Counter works more than 1 year without replacing batteries
- COUNTING BY THE HOUR: Hourly statistics provide greater detail and understanding of behavior, helps to identify patterns, plan workload, improving the efficiency of the enterprise
Orient a fan or pan-tilt mechanism
Feed reported face position into a host program that controls a servo or other actuator. Useful Sensors describes orienting a fan toward the nearest person; a pan-tilt mount is another possible maker adaptation. Mechanical limits and safe movement need to be handled by the build.
Make a screen-lock trigger
The official guide links a screen-lock project. A host can use presence data as one input to a lock or wake workflow, with the operating system or application responsible for the actual security behavior.
Rank #4
- Intelligent sensor design - easy to operate sensor switch, wave or touch to open and close automatically, no need to operate 5 minutes automatic operation
- All-weather auto-maintenance - Cycle purification every 3 hours, combined with 20-second cleaning and 100-second air drying to ensure a dry toothbrush
- Continuity - The toothbrush adopts Type-C fast charging technology, 5600 mAh battery, three hours fully charged, up to 160 days of battery life, not afraid of power outages
- Easy to Install - The strong backing that does not hurt the wall adapts to smooth walls, no need to drill holes, easy to complete the installation, load-bearing and firm without leaving marks
- Package Includes - 1 x 5-Person Toothbrush Cleaner, 1 x USB Cable (Adapter not included - please use 5V-1A adapter to charge the toothbrush cleaner), 1 x Wall Bracket, 1 x Backing Adhesive, 1 x Instruction Manual
Build an occupancy indicator or connected installation
Use detection data to drive an LED, an art installation, or an occupancy indicator. For a connected version, a host can forward data over a network. A Hackaday project combines the Person Sensor, a Blues Wireless Notecard, and a host microcontroller to relay person-detection data to the cloud; check current component and service costs independently.
What the published specifications tell you
Make:’s review, published December 20, 2024, lists dimensions of 19 mm × 16 mm and a price of $10 at the time of its review. Those are historical review details, not a current price or availability guarantee. Check a seller for current stock and pricing before planning a build.
The documented interface and supported examples help establish how the module can fit into a prototype, but the available sources do not provide a quantitative accuracy benchmark or environmental test matrix. Test it in the intended distance, lighting, enclosure, and placement rather than assuming a particular detection range or reliability.
Privacy and practical limits
The official guide includes a Privacy section and describes the module as hiding its internal implementation behind the hardware interface. That abstraction can simplify integration, but it is not an independent privacy audit. The sources also do not establish a universal accuracy guarantee or production-grade biometric performance.
Before using the module in a shared or public space, decide what detection information the host needs, what it will store or transmit, and how people will be informed. Validate behavior in the actual installation, especially if a detection result controls access, records presence, or triggers a safety-sensitive action.
Quick Recap
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