Smart keypad switch array project

 Project Title:

Switch Array Matrix Using Push Button  and LEDs

Objective:

To create a matrix-based switching system using mechanical switches.

Components Required:

S.N. Component Quantity

1 Push Button Switch 100

2 Green LEDs (5mm) 10

3 Resistors (330Ω – 470Ω) 10

4 Power Supply (5V DC) 1

Circuit Description:

ckt diagram

                      

The switch matrix consists of 10 rows and 10 columns, forming a 10x10 grid of switches.

One terminal of each switch is connected to a horizontal row line, while the other terminal connects to a vertical column line.

Each row line is connected to a resistor, followed by a green LED, which leads to ground.

A 5V DC supply is provided to all column lines.

When a switch is pressed, it closes the circuit between a column (positive supply) and a row (connected to LED and resistor to GND), causing the LED in that row to glow.

generally 10k ohm resistor are used for pullup/down for 5V power so here used for define specific logic state to avoid floating state.

   

Working Principle:

Each switch connects a specific column (power line) to a row (LED + resistor to ground).

When a switch is pressed, current flows from the 5V column line through the switch into the row line, passing through the LED-resistor pair to ground.

This illuminates the corresponding LED connected to that row.

The system uses no microcontroller; it's based entirely on direct wiring and basic electrical logic.

Applications:

Demonstration of matrix scanning logic without digital control.

Educational tool to understand current paths and LED activation logic.

Can be extended for simple input/output control boards.

Advantages:

Simple and low-cost implementation.

No programming or controller is needed.

Good for learning manual switching logic and matrix structure.

Limitations:

Only one LED per row glows at a time (depending on switch press).

Cannot detect multiple switches pressed simultaneously per row correctly .

Not scalable for advanced logic control without microcontroller or ICs.

Recommendations:

Add diodes to each switch leg to prevent ghosting if multiple switches need to be pressed at once.

Use modular PCB design for easier wiring and error detection.

Consider integrating microcontrollers in future versions for scanning and detection.

References:

I do not have exact reference sites, but I referred to YouTube videos, books, and ChatGPT  for understanding and building this project.