Introduction: Interfacing of LCD With Arduino Uno by Using Only 3 Pins

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To interface LCD we need six digital pins from Arduino. To save your Arduino pins and easy interfacing

IC 74HC595N Shift Register is used.Using this shift register we can interface LCD using 3 pins.

Step 1: Components Required

1)Arduino Uno/Nano/Mega

2)LCD 16x2

3)1K Pot (Variable Resistor)

4)IC 74HC595N (Shift Register)

Step 2: Setup

To interface LCD using three pins follow the below steps

To interface LCD using 3 pins you need to Update the ARDUINOLiquidCrystal libraries.Which is located at the following location Local Disk(C)-->Program Files-->Arduino-->libraries-->LiquidCrystal. Open the LiquidCrystal folder and there are some files inside that folder.Cut and paste these files Some where on your pc. Because you need to use these files when you interface LCD using 6 pins. Now Download and Extract the following libraries.Which is an updated Liquid Crystal libraries to use LCD with 3 pins.Copy the extracted files and paste it in the following Location Local Disk(C)-->Program Files-->Arduino-->libraries-->LiquidCrystal. Note: open the folder of Liquid Crystal and paste it. Now you have updated your Arduino Liquid Crystal libraries.

Connections are shown in schematic.

Find Attached Library

Step 3: Code

Find attached code for this and run on Arduino IDE.

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