As long as the single chip microcomputer (including crystal circuit) and digital tube (4 bit) and 5 triodes (used as bit drivers and buzzers of digital tube), then a few buttons and buzzers. However, beginners are more difficult to make, because the program is more complex, coupled with no ready-made circuit board, welding is not reliable, hardware and software problems affect each other, the possibility of success is relatively small, it is better to buy a single chip microcomputer development board, which has a digital tube and LCD screen, and some clock chip (ds1302), after the success of the experiment, if you want to do it yourself, design your own circuit board. It can also be joined with a universal board