I believe that many electronic enthusiasts, especially the enthusiasts who have been in contact with the microcontroller, have a topic that can’t go around, that is, to make an electronic clock. If I make one, the effect is pretty good.
(1) Design principle diagram. There are several main parts: 51 single -chip microcomputers and its peripheral circuits, digital tubes and LED driver circuits for second display, DS3231 high -precision clock circuit (annual error is about 1S), key circuits, optical detection circuits, and power conversion circuits.
(2) Design PCB and hairboard factories. Here I chose to only do the core board. It is also considered that the 2.3 -inch digital tube is a bit large. In addition, the board factory (a certain creation) has 5 yuan per month for free shipping 10cm* 10cm* 10cm proofing opportunities, so there are many costs left.
(3) Welding PCB of reserve devices. I specially chose this large packaging device such as 1206, 0805 to facilitate novice welding.
(4) After the welding is completed, the “soul” must be injected to burn the program to the single-chip machine. For details, please refer to the STC-ISP single-chip recording method of Hongjing Company.
(5) The next thing is to find a large universal board and arrange 4 2.3 inches and two LED lights. Then connect the terminals of the core board to the data bus corresponding to the universal board. The universal board is relatively thin. I give a reinforcement role to the two -day thick copper paint. In the end:
(6) The previous is that the digital tube definitely does not conform to my aesthetics. The acrylic of an acrylic with a tea colors is taken out of 502 glue, and the face value is instantly improved.
(7) Link the 12V power supply to see the final effect.
(8) After running for a period of time, the brightness is high during the day, the digital tube automatically increases the brightness, the lights are extinguished at night, and the digital tube automatically reduces the brightness. Thanks to large -sized digital tubes, it can be seen very clearly. The accuracy of this clock chip is very high, and it is basically no error in running for a period of time.