Changshu Polytechnic Lichuang Cup Group B Li Haowei Huang Tianqi's work

This project uses a 38-bit decoder, a 555 timer and a binary counter 74LS191 to realize the lighting effects of running lights, constant lights and delayed lights.

The left and right running water lamp circuit uses the 555 chip as a multivibrator to generate rectangular pulses to provide a pulse source for the counter, and its duty cycle can be changed by adjusting the resistance of the potentiometer to achieve the effect of controlling the water flow rate of the running water lamp. The 74ls191 in the subsequent circuit is used for counting and can control the high and low levels of pin 5 ( U/D counting control terminal) through the switch to control the left and right flow direction of the water lamp. A piece of 74ls138 controls the on and off of 8 small LED lights.

The touch delay lamp uses a 555 timer to form a monostable trigger. Its working principle is that it can flip from a stable state to a temporary stable state under the action of an external trigger pulse. After maintaining the temporary stable state for a period of time, the circuit Can automatically return to steady state.

This design is a basic digital electrical circuit. In order to simplify the circuit and facilitate debugging, analog electrical circuits and microcontrollers are not used. Therefore, in the final design, it was not possible to add a voice-activated light group circuit and a photosensitive strobe circuit, and it was also impossible to use a single-chip microcomputer to create a better lighting effect, so it needed to be improved.