Double-sided billboard principle
作者：苦伯元 | 发布日期：2024-09-24 21:51:52
Why can the pictures on the billboards on the road automatically jump one by one? What principle is used?
It is designed like a roll of paper. There is a shaft below that rotates, and the advertising screen is pulled down. After each pull is completed, the upper shaft rotates and pulls up, and so on.
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