People Counter Circuit using 7 Segment Display, Laser
Hello friends! Welcome back to ElectroDuino. This blog is base on the Object/ People Counter Circuit using 7 Segment Display and Laser. Here we will discuss Introduction to Object/ People Counter, Project Concept, Block Diagram, Components Required, Circuit Diagram, Working Principle.
Introduction
In this project, we will design a Counter Circuit, which can count objects as well as people. When someone or an object crossing in front of this system, this system counts, and every time add +1. This system can count up to 999 people or objects at a time. It has a reset button, which is used to reset at any point. We can use this device at the shop, conference hall, school, and other places to count visitors.
Project Concept
This system consists of 5 key components, these are laser pointer, LDR, LM358 Comparator IC, NE555 timer IC, CD4033 Counter IC, and 7 Segment display. The laser pointer continuously emits laser light, which falls on the LDR surface. This LDR is connected to the LM358 comparator IC. When any object or person comes between the laser and LDR, then the LM358 is output will change. This output gives to the CD4033, then this IC operates the 7 segment display. As many times laser light disconnect on the LDR surface, every time the Counter IC add +1 on the display. Here we will use 3 CD4033 ICs to control the 3 7 segment displays. Also, this system has a reset button, which is used to reset the counter at any point.
Object/ People Counter Circuit Block Diagram
Components Required
| Components Name | Quantity |
| LM358 Op-Amp IC (U1) | 1 |
| NE555 Timer IC (U2) | 3 |
| CD4033 Counter IC (U3, U4, U5) | 2 |
| Laser Pointer | 1 |
| LDR (R1) | 1 |
| 10K Potentiometer (RV1) | 1 |
| 10K ohm Resistors (R2, R3, R4, R5, R6) | 5 |
| 150 ohm Resistors (R7) | 1 |
| Push-button switch | 1 |
| 7 Segment Display | 3 |
| LDE (Red and Green) | Each 1 |
| Slide Switch (SW1) | 1 |
| Terminal Block | 1 |
| 9V Power Supply | 1 |
| PCB board | 1 |
| Connecting Wire | As required in the circuit diagram |
Tools Required
| Tools Name | Quantity |
| Soldering Iron | 1 |
| Soldering wire | 1 |
| Soldering flux | 1 |
| Soldering stand | 1 |
| Multimeter | 1 |
| Desoldering pump | 1 |
| Wirecutter | 1 |
Circuit Diagram Object/ People Counter Circuit using 7 Segment Display, LDR, and Laser
Working Principle of Object/ People Counter Circuit using 7 Segment Display, LDR, and Laser
At first, we need to install this system perfectly, the laser pointer placed on one side of the door, and the circuit placed on another side of the door. Remember one thing that the laser light always falls on the LDR surface.
In this circuit, the LDR is connected with a pull-down resistor, and the output pin of the LDR is connected to pin 3 ( Non-Inverting) of the LM358 comparator IC. A 10 k potentiometer signal pin is connected to pin 2 (Inverting) of the LM358 comparator IC, it is used to set a reference voltage at the Non-Inverting input (pin 3) of the IC.
When any people or objects cross between the Laser pointer and LDR, then the LDR output goes LOW, because there is no light fall on the LDR surface. This output voltage is given to the LM358 IC, now the IC compares this voltage with the reference voltage. But in this condition, this voltage is less than the reference voltage, so the output of the LM358 comparator IC is LOW (Ground).
Then this output goes to pin 2 (trigger) of the NE555 timer IC. Here the NE555 IC works as a monostable mode, so when its pin 2 (trigger) gets the ground voltage from the LM358 IC, then the timer IC output pin 3 provides High output for a fixed time. This output goes to the Clock input of the 3rd CD4033 (IC 5) IC. Then this IC starts to print numbers on the 3rd 7 Segment Display. When this IC count 9, then it provides output to the Clock input of the 2nd CD4033 (IC 4) IC. When the 2nd IC count 9, then it provides output to the Clock input of the 1st CD4033 (IC 3) IC. This way, this system can count up to 999. The Pushbutton is used to reset the counter at any point.
