How does the automatic door sensor work?

Time-of-flight, referred to as ToF technology, its core principle is to calculate the distance between the sensor and the target object by measuring the time it takes for light (usually invisible infrared laser light) to travel back and forth between the sensor and the target object.

The transmitter inside the sensor continuously emits modulated infrared laser pulses with a specific waveform across the entire detection area. When these photons encounter people or objects within the detection area, they are reflected, and some of them return to the sensor along the same path. A high-precision receiver inside the sensor captures these returning photons and calculates the time difference between "transmission" and "reception," thereby calculating the distance.

3D-TOF camera: The sensor emits an array of light covering a wide area, and its receiver is a pixel array. This is equivalent to a 3D image. When used in automatic door sensors, TOF technology can clearly identify a person's complete outline and determine whether they are approaching the door, standing still in front of it, or moving away. For stationary people, TOF can continuously sense their presence and command the door to remain open, greatly improving safety.

Scanning TOF: By using technologies such as micro-electromechanical systems (MEMS) lenses to allow a single laser beam to quickly and systematically scan an area, constructing a depth map through point-by-point measurement.

Like CANBO 903 series, laser safety curtain sensor, utilizes TOF technology, with six beams forming a light curtain. It is used for anti-pinch and anti-collision safety for automatic swing doors.