【Training Camp】Little self-written clock

Project summary: 1. A USB to TTL circuit and an external battery interface are added, which can be independently powered. 2. The four pins related to the USB to TTL circuit are led out with pin headers. They can be burned using an external programmer alone, or a serial port can be used. At the same time, the development board can also be used as a burner to increase its functional diversity. Optimization suggestions: 1. The 3D shell of this project does not use official cases. It is designed by itself. The 3D printing material uses toughened photosensitive resin, and the material strength is completely It is enough to be used. If you want to further reduce costs, you can further expand the opening of the support plate so that the support plate becomes a support frame structure. 2. The thickness of the 3D shell is 3mm. Same as above. If you want to further save costs, you can modify the thickness to 2mm or 1.5mm. 3. The position of the servo installed on the 3D shell should be appropriately elevated. You can use auxiliary spacers or modify the file directly. 4. The diameter of the fixing hole in the shell design is 1.75mm and the depth is 6mm. In actual printing, due to There will be an error of 0.1mm due to material reasons, and the thickness of the two arm fixings can be up to 6mm, so when purchasing self-tapping screws, you must pay attention to the length. It is also recommended to purchase the corresponding anti-slip nuts. Disadvantages: 1. Mainly because the actual design is ignored The material had an error of 0.1mm when printing, so there was a problem with the fixing screws. The homemade simple fixing device used had a great impact on the accuracy. 2. The purchased servo did not have a corresponding 3D size, but after careful measurement The impact of the steering gear can be ignored.