Automatic time synchronization stamp

Project Introduction:
This is a palm-sized mechanical Bluetooth stamp that fits easily in a pocket. When needed, simply press a button and wait a few seconds for automatic time synchronization. It costs only around 50 yuan. It connects to Bluetooth for time synchronization, and when the button is pressed, it activates a stepper motor to drive the corresponding gears to the designated position, thus printing the hour and minute of the current time. Normally, it enters a low-power sleep mode.
Hardware
Solution: The main controller uses an STC8H microcontroller (programming requires a USB-to-TTL programmer). To save space, the circuit board does not include a programming chip or Bluetooth module, so the Bluetooth module needs to be connected externally via USB.
The clock chip used is the DS1302, a classic clock chip that needs no further explanation.
Instructions: Upon
initial power-up, you can connect via Bluetooth and control the time and calibrate the gear positions through a mobile app. Pressing the button sends 10 bytes of data via serial port. Excluding the header byte 0XA5, the second-to-last checksum, and the tail byte 0X5A, the data in the middle represents the hours, minutes, seconds, and the current position of the four gears. You can also calibrate it by sending corrected hour, minute, and second data, along with the required number of pulses for each of the four motors, in the same data format. See the attached code for the specific
software code . Note: The power can be restored via USB; a green light will illuminate when fully charged. Circuit board components can be purchased online. I used a stepper motor model 21SRA0605021, but you can use other models; simply modify the casing according to your needs. Project casing models are attached. [ Image of the actual product]