You can count visitors entering and leaving with an ESP32 by detecting the order in which they pass through two sensing zones. A documented approach uses a VL53L1X time-of-flight sensor, ESP32 firmware and MQTT to report each completed passage to Home Assistant or another service that maintains the room count. It is a practical project pattern—not a validated commercial counter—so placement and thresholds need testing at the actual doorway.
How an ESP32 visitor counter determines direction
A single sensor that reports only an interruption can tell that something crossed its sensing line, but not whether it was entering or leaving. Direction requires additional information. The Andrea-Fox peopleCounter project uses two virtual zones and infers direction from their activation order.
For one direction, the project recognizes this sequence: neither zone is occupied, zone one is occupied, both zones are occupied, zone two is occupied, then neither is occupied. The reverse order indicates travel in the opposite direction. The completed sequence becomes a passage event.
The VL53L1X measures distance using time-of-flight laser pulses. In the project’s logic, a zone is occupied when the measured distance falls below a configured threshold. This is not person identification: the system counts detected passages, and its success depends on the sensor seeing the expected sequence.
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What you need
- An ESP32 development board. The project also describes ESP8266 support, but this guide focuses on ESP32.
- A compatible VL53L1X breakout board. The project names SparkFun’s library and reports that it can also work with a Pololu VL53L1X board; it says other boards were not tested.
- Wiring appropriate to the breakout and the selected ESP32 board.
- Firmware built with Arduino-ESP32 or Espressif’s ESP-IDF.
- An MQTT broker and a receiver such as Home Assistant if you want to report passage events to a larger system.
Connect the VL53L1X to the ESP32
The project’s example wiring is shown below. These are example connections, not mandatory pins for every ESP32 board or sensor breakout. Espressif documents I2C support through the GPIO matrix, so confirm your board’s pinout and the breakout’s voltage requirements before connecting it.
| VL53L1X breakout | Example ESP32 connection |
|---|---|
| VIN | 3V3 |
| GND | GND |
| SDA | GPIO21 |
| SCL | GPIO22 |
The cited project describes its pulses as invisible and eye-safe, but that description is not a substitute for a broader safety certification. Check the sensor manufacturer’s current documentation for product-specific guidance.
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Mount and tune the sensing zones
The project suggests mounting the sensor above the door frame or at the side; side placement may be more convenient for a wide doorway. Choose a location where the intended path through both zones is detectable, then adjust the zones and distance thresholds to the doorway’s geometry.
The project describes ToF distance readings as independent of ambient lighting and target color, shape and texture, while noting that those target characteristics can affect maximum range. It does not publish a validated maximum doorway width, mounting tolerance or accuracy under crowding.
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Before using the result operationally, test the installation with people moving in both directions and at different walking speeds. If side-by-side traffic is possible, test that too: overlapping or occluded movement can prevent the expected sequence from being detected reliably. Do not assume a result from a narrow, one-person-at-a-time doorway applies to a wider entrance.
Build the firmware and send passage events
You can implement the sensing logic with Arduino-ESP32 or Espressif’s native ESP-IDF framework. The current Arduino documentation page identifies Arduino Core for ESP32 version 3.3.12 as based on ESP-IDF 5.5; the ESP-IDF guide describes version 6.0.1. Follow the documentation for the version actually installed rather than combining APIs from different releases: Arduino-ESP32 documentation and ESP-IDF v6.0.1 guide.
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The reference project publishes passage events over MQTT. A receiver such as Home Assistant can update the occupancy count, keeping the sensor’s job—detecting and reporting a passage—separate from the service’s job of maintaining the count. The project’s code takes the Wi-Fi network name and password, broker address and port, and optional MQTT credentials as configuration. Keep secrets out of public repositories and shared code.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.When to consider break-beam sensors instead
Two break-beam sensors can also infer direction from the order in which their beams are interrupted. They may be easier to reason about when a clean line across the entrance and mounting access on both sides are available. A two-zone ToF arrangement may suit a site where its distance-based sensing and mounting position are more practical. These are design considerations, not results from a controlled comparison; the cited sources establish no accuracy winner.
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For a wide opening or side-by-side traffic, assess sensing coverage and occlusion before choosing either design. The cited project does not report controlled accuracy results, a throughput limit or a visitor-count accuracy percentage, so none should be assumed.
What the ESP32’s pulse counter can and cannot do
Espressif’s ESP32 datasheet documents a hardware pulse counter, or PCNT, for counting input pulses. It can help count signal edges, but a single pulse stream does not inherently identify whether someone entered or exited. Direction still requires multiple sensors or another source of directional information.
For the documented ToF approach, the useful output is not simply an edge count: it is a completed sequence across two zones. That distinction matters when choosing a design and deciding what the receiving software should count.
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