1. Introduction to application scenarios
The projector is installed in the elevator car, projecting directly to the elevator door, and playing advertisements and other videos to passengers in the elevator. When the elevator door is opened, the projector turns off projection; when the elevator door is closed, the projector plays projection. The HPS-3D160PRO lidar can be embedded in the projector as a sensor to detect the opening and closing status of the elevator doors. It can detect the opening and closing status of the elevator doors in real time and output related signals according to the status to control the linkage of the projector.
2. Application Principle
When the elevator door is closed and opened, HPS-3D160PRO can measure the distance from the elevator door to the outside of the elevator door from the inside of the elevator car. According to the difference between the two distance values, the open and closed state of the elevator door can be judged, so as to control the operation of the projector to turn on and off the projection.
A distance threshold can be set, which is greater than the distance between the inside of the elevator and the elevator door, but less than the maximum distance between the inside of the elevator and the outside. (As shown below: A＜C＜B)
The distance threshold (Th) is C, which is a fixed value, but should be adjustable.
When the elevator door is closed, the distance measurement (Distance) is A.
When the elevator opens the door, the distance is B.
Distance＜C, indicating that the elevator door is closed; Distance＞C, indicating that the elevator door is open. In this way, the opening and closing status of the elevator door can be monitored in real time, so that the associated signal can be generated at the back end to control the action of the projector.
Three, application development program example
As an application to monitor the opening and closing status of elevator doors, the distance value can be converted into a switch state to facilitate the reading of the status of the projector controller. Lidar can be converted through the conversion board and output the switch value. Customization can be accepted according to demand.
The installation height and position of the projector should consider the actual installation environment of the elevator. It can be installed at a higher position at a certain angle to avoid the projection light being blocked by passengers. At the same time, the light emission angle of the lidar should be considered to ensure that all the emitted light can exit the elevator door and not be blocked by the edge of the elevator door.
In order to avoid the jitter of the ranging distance value in a short period of time, causing the projector to malfunction, a protection function can be added for outputting after n consecutive data meet the conditions. At the same time, in order to ensure the timeliness of the switching action, the value of n is not easy to be too large.