Traditional mechanical door locks generally use keys to open the door, while the main unlocking methods of smart door locks include: fingerprint recognition, password unlocking, NFC device unlocking, mobile APP unlocking, etc. These unlocking methods are mature, safe and stable. So, what role does laser play in smart door locks?

Laser is mainly used in smart lock sensors, such as infrared and lidar sensors. The principle of the infrared sensor is to use an infrared transmitter to emit infrared rays at a certain angle, and the receiver to receive the signal at a certain angle. Infrared sensors are widely used in medicine, military, environment and other fields, such as common temperature measuring guns, infrared thermal imaging cameras, etc. Infrared sensors are low cost, simple in structure and highly responsive. But at the same time, the measurement distance and accuracy of infrared rays are relatively poor. The light is easily absorbed by black and difficult to be captured by the receiver.

There are two main types of lidar sensors, single-point TOF and structured light. The TOF principle is that the laser transmitting tube emits infrared laser, the receiver calculates the time difference between emission and reception, and the distance can be calculated based on the speed of light. Structured light is a laser emitter that emits a light spot, and the distance is determined by calculating the size of the light spot. The advantages of lidar are measurement accuracy and high precision. The disadvantages are high cost and susceptibility to environmental factors.