In this circuit, quartz crystal oscillator is used as a time-based pulse oscillator, and second time-based signal is obtained after digital frequency division. The time is displayed through the counter, decoder and display. The crystal oscillator is used as the time base pulse, so the travel time is accurate.

Circuit installation and debugging:
Weld according to the sequence of the component list, and install the lower component first and then the higher component. The integrated circuit shall be installed on the pipe socket first, and then the integrated circuit shall be installed on the pipe socket finally.
Elements that do not distinguish the pin direction: resistor, crystal oscillator, ceramic chip capacitor, toggle switch.
Elements with positive and negative poles: the long legs of the LED and electrolytic capacitor are positive poles, facing the position marked with+on the circuit board, and the position with black circle of 1N4148 faces the position with white mark on the circuit board.
The notch position of the IC base is aligned with the direction of the notch position of the circuit board. Similarly, the notch position of the integrated circuit is aligned with the notch mark of the circuit board. The position that can be installed normally by touching the switch is correct.
Pin sequence recognition: the chip text is aligned with itself, and the first pin from the lower left corner is 1 counter clockwise.