Digital Visitor Counter with 8085 Microprocessor

Digital visitor counter is a reliable circuit that takes over the task of counting Number of Persons/ Visitors in the Room very accurately. When anybody enters into the Room then the Counter is Incremented by one and when any one leaves the room then the Counter is Decremented by One. The total number of Persons inside the Room is displayed on the seven segment displays.

The microprocessor do the above job it receives the signals from the sensors, and this signals operated under the control of software which is stored in the Memory. The sensors are made with help of LDRs which are Light Dependent Resistors, whose Resistance is inversely proportional to the Light falling on it. The Laser Torch is used as the Light source and it is focused on the LDRs, the Microprocessor continuously watches the LDRs. 

Circuit

Flowchart

Block Diagram

Program

MEMORY ADDRESS	LABEL	MNEMONICS	OPCODE	COMMENT
4110		MVI A,81	3E	Initialize the Port C   as Input
4111			85
4112		OUT 0F	D3
4113			0F
4114		MVI A,01	3E
4115			01
4116		MVI C,03	0E
4117			03
4118		CALL 0005	CD	Clear the Displays in the Kit
4119			05
411A			00
411B		MVI A,00	3E
411C			00
411D		STA 4200	32	Clear the count
411E			00
411F			42
4120		STA 4201	32
4121			01
4122			42
4123		STA 4202	32
4124			02
4125			42
4126		MVI A,03	3E
4127			03
4128		MVI C,08	0E
4129			08
412A		LXI H,4201	21
412B			01
412C			42
412D		CALL 0005	CD	Display zero on
412E			05	The display
412F			00
4130	START:	IN 0E	DB	Check ldr1
4131			0E
4132		ANI 01	E6
4133			01
4134		JZ UP	CA
4135			52
4136			41
4137	LOOP:	IN 0E	DB
4138			0E
4139		ANI 02	E6
413A			02
413B		JZ LOOP	CA
413C			37
413D			41
413E		LDA 4200	3A
413F			00
4140			42
4141		INR A	3C	Increment count
4142		STA 4200	32
4143			00
4144			42
4145		CALL DISPLAY	CD	Display the count
4146			77
4147			41
4148	LOOP1:	IN 0E	DB
4149			0E
414A		ANI 02	E6
414B			02
414C		JNZ LOOP1	C2
414D			48
414E			41
414F		JMP START	C3	Jump to main routine
4150			30
4151			41
4152	UP:	IN 0E	DB	Check ldr2
4153			0E
4154		ANI 02	E6
4155			02
4156		JZ START	CA
4157			30
4158			41
4159	LOOP2:	IN 0E	DB
415A			0E
415B		ANI 01	E6
415C			01
415D		JZ LOOP2	CA
415E			59
415F			41
4160		LDA 4200	3A
4161			00
4162			42
4163		DCR A	3D	Decrement count
4164		JC LOOP4	DA
4165			74
4166			41
4167		STA 4200	32
4168			00
4169			42
416A		CALL DISPLAY	CD	Display the count
416B			77
416C			41
416D	LOOP3:	IN 0E	DB
416E			0E
416F		ANI 01	E6
4170			02
4171		JNZ LOOP3	C2
4172			6D
4173			41
4174	LOOP4:	JMP START	C3	Jump to main routine
4175			30
4176			41
4177	DISPLAY:	MOV B,A	47	subroutine for display
4178		ADI 06	C6
4179			06
417A		MOV D,A	57
417B		ANI 0F	E6
417C			0F
417D		MOV C,A	4F
417E		SUI 09	D6
417F			09
4180		JC HERE	DA
4181			92
4182			41
4183		JZ HERE	CA
4184			92
4185			41
4186		MOV A,B	78
4187		ADI 0C	C6
4188			0C
4189		MOV D,A	57
418A		ANI 0F	E6
418B			0F
418C		STA 4202	32
418D			02
418E			42
418F		JMP NEXT	C3
4190			96
4191			41
4192	HERE:	MOV A,C	79
4193		STA 4202	32
4194			02
4195			42
4196	NEXT:	MOV A,D	7A
4197		ANI 0F	E6
4198			0F
4199		RLC	07
419A		RLC	07
419B		RLC	07
419C		RLC	07
419D		STA 4201	32
419E			01
419F			42
41A0		LXI H,4201	21
41A1			01
41A2			42
41A3		MVI A,03	3E
41A4			03
41A5		MVI C,08	0E
41A6			08
41A7		CALL 0005	CD	Display the new count
41A8			05
41A9			00
41AA		RET	C9