Design and Application of LED Rocker Based on Single Chip Microcomputer (1)

LED light-emitting diode

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

100V, 250mA, surface mount, high speed switching diode

0 Preface

With the development of modern technology, high-tech products have brought great convenience to people because of their simplicity and portability. The “shake stick” brings people a refreshing feeling with its simpler and more novel information transmission method, and will also bring people a new convenient cultural transmission method, which is often used in parties and large-scale entertainment programs. occasion.

This article uses interesting research to design and design an electronic device (referred to as a "shake stick") that uses 16 pre-programmed programs to control 16 LEDs and display the characters and simple graphics with the shaking of the left and right hands. This device uses the AT89C51 microcontroller to control the LED array. The ball switch is used to detect the current shaking state, and the single-chip microcomputer controls 16 LEDs to perform refreshing and refreshing of different frequencies, so that the information such as the output text and the pattern can be displayed by shaking, thereby achieving the function of conveying information on the visual plane.

1 The composition of the hardware system

The simple and interesting LED rocker of this design is an electronic device based on single-chip control. With buttons for screen switching and ghosting, the screen is clearly displayed. It is mainly composed of the control part of the MCU, the LED driving part and the LED display part. The hardware composition block diagram is shown in Figure 1.

1.1 button module

In this design, the displayed content is switched by a screen change switch. In the design, the ball switch can be used to control the rocker to display information when it is shaken to one side. Otherwise, a mirror image or mirror image will appear, which is a phenomenon of ghosting. The optional rocking control switches are available in both mercury and ball switches. Mercury switches have higher stability but are less secure. Although the ball switch is slightly less stable, it is not easily broken and has a high degree of safety. Considering the actual application environment, the ball switch is selected as the shaking control of the system, and the instability caused by the ball switch can be compensated by software. The function of the manual reset switch is to control the start and stop of the system.

1.2 Control section

As the control core of the whole system, the minimum system of the single chip microcomputer is mainly responsible for controlling the brightness and display of the diode. The display effect of the rocker is controlled by software programming and external interruption of the microcontroller.

1.3 LED display module

In this design, the display portion is designed according to the display principle of the LED dot matrix. The display of the dot matrix is ​​divided into two types: row scanning and column scanning. The column scanning is to input the font array through the row driving of the dot matrix screen, and then scan each row through the column, when the column is low (high) level. When the behavior is high (low) level, it means that the point is a part of the pattern, and it is read and displayed. The LED display stick data transmission principle of this design is similar to that of the LED dot matrix screen. Think of the LED display stick as a column in the LED dot matrix screen. In order to make the displayed pattern clear, 16 high-brightness LED tubes are used in the design to arrange them in a row. The entire screen is equivalent to 16 rows × 1 column when it is still. Data transmission and column scanning are also used for data transmission. In the swinging process, applying the principle of visual persistence of the human eye, the illuminated column does not disappear quickly, but continues to move forward with the direction of the swing, as long as the moving speed is higher than the shortest time of the visual persistence. The display content will not go out, so that a pattern can be "swinged" out like this.