1. Functional description

MCU connects 12864 (st7920) LCD and one key to INT0 to simulate a lottery machine.

LCD initial display "Good luck!" ;

Press the button, LCD display "start lottery", and then display "3-2-1" countdown, resulting in 20 (0-4) random numbers;

LCD screen shows "Prize 1", "Prize 2", "Prize 3" and "Thank you for your participation" according to random number.

Finally, the LCD screen shows the result of the lottery: "Congratulations on your winning: XXX".

Press the button again and start the lottery again. The LCD shows "Start the lottery"... Such a cycle.

2. Circuit diagrams designed in PROTEUS

 

3. Source code

 

#include <config.h>
#include <stdlib.h>
#include <12864.h>

sbit p=P2^0;
void delay_ms(u16 x)//Millisecond delay function
{
	u16 i,j;
	for(i=0;i<x;i++)
	    for(j=0;j<115;j++);
}
void main()
{
	u16 m,n;
	p=0; 
	EA=1;
	IT0=1;
	EX0=1;
	//Initialization
	lcd12864_init();

	lcd12864_pos(1,2);
	LCD12864disp("Good luck!");
    while(1){
	if(p==1)
	{
			m=rand();
			srand(m);
			lcd12864_clear();
			//Count down
			lcd12864_pos(0,2);
			LCD12864disp("Start raffle");
			lcd12864_pos(2,3);
			LCD12864disp("３");	
			delay_ms(1000);
			lcd12864_clear();

			lcd12864_pos(0,2);
			LCD12864disp("Start raffle");
			lcd12864_pos(2,3);
			LCD12864disp("２");	
			delay_ms(1000);
			lcd12864_clear();

			lcd12864_pos(0,2);
			LCD12864disp("Start raffle");
			lcd12864_pos(2,3);
			LCD12864disp("１");	
			delay_ms(1000);
			lcd12864_clear();
		//Random Generation of 20 Display Awards
		for(m=0;m<20;m++)
		{
			n=rand()%5;
			lcd12864_pos(2,2);
			switch(n)
			{
				case 0:LCD12864disp("The first prize!");break;
				case 1:LCD12864disp("１Prize!");break;
				case 2:LCD12864disp("２Prize!");break;
				case 3:LCD12864disp("３Prize!");break;
				case 4:LCD12864disp("Thanks for your participation.");break;
			}	
			delay_ms(200);
		}
		lcd12864_pos(0,1);
		LCD12864disp("Congratulations on your acquisition:");

	}
	p=0;
	delay_ms(20);
	}
}


void intr0() interrupt 0	  //
{
	p=~p;
} 

4. Experimental results

Because I can't upload videos, so I upload effect videos to Youku, please click and watch - --->. Video of lottery effect