Published July 17, 2021 © GPL3+

LCD reactive bot

A simple project using I2C LCD display, that reacts to proximity, illumination and movement.

BeginnerFull instructions provided959

Things used in this project

Hardware components

DFRobot I2C 16x2 Arduino LCD Display Module

I2C LCD display

Arduino UNO

High Brightness LED, White

High Brightness LED for illumination.

Resistor 221 ohm

Resistors for the LEDs.

LDR, 5 Mohm

PIR Motion Sensor (generic)

For detecting moviment

Ultrasonic Sensor - HC-SR04 (Generic)

Resistor 10k ohm

Breadboard (generic)

Male/Female Jumper Wires

Jumper wires (generic)

Software apps and online services

Arduino IDE

Story

Hello, in this tutorial, I will show how to make a LCD reactive bot, that reacts to movement, proximity and illumination.

Installing some Libraries

Before Starting with connections and programming, we need some Libraries:

We are going to use a LCD display with I2C Module, because it is more easy to program and don't use any digital pin of our Arduino. It just needs a library, that is LiquidCrystal_I2C. To install it is very simple: Open your Arduino IDE, go to Tools → Manage Libraries...

This will open the Library Manager.

Library Manager

Now, go to search bar:

Search bar

Now, type "LiquidCrystal I2C, and this will be the result:

The result

Search the library: LiquidCrystal I2C:

Searching the Library

Then, we click on "Install":

install the Library

Installed the LiquidCrystal I2C Library, let's continue to the next Library

To use an ultrasonic sensor with Arduino, we need a another library, that can be downloaded here.

After downloading the library, go to your IDE, and open: Sketch→Include Library→Add.ZIP Library.

Search the file at your downloads, that is named as Ultrasonic.zip and select it.

Now you have the library.

The Idea

I2C LCD Display have 4 pins, here is the image:

I2C LCD Display

We will connect the SDA pin on A4 of Arduino (Analog 4) and SCL pin on A5 of Arduino (Analog 5). Gnd attached to Gnd of Arduino (Ground).

Here is the schematic of the LCD Display connections:

Click on image for a better view.

Connections (Gnd to Arduino Gnd, VCC to +5v, SDA to A4 and SCL to A5)

The idea is using the LCD Display to make a animated face with eyes:

The face

Two ultrasonic sensors will be used to make this face move. Here is the Ultrasonic sensor pinout:

Ultrasonic sensor pinout

Here is the connection of the ultrasonic sensor to Arduino:

Click on image for a better view.

the connection

So, here, if the right sensor detects proximity, the face eyes will move to right, if the left sensor detects proximity, the face eyes will move to left.

The face when the right sensor detects proximity.

the face when the left sensor detects proximity.

In this project, we are going to use a PIR sensor, that detects movements, so the next idea is: if it detects movement, the LCD Display backlight turns on, if not, the backlight turns off.

The Display when the PIR sensor don't detect any movement.

Here is the connections of the PIR sensor to Arduino:

Click on image for a better view.

PIR sensor connections

This project also have a LDR (Light Dependent Resistor), for detecting illumination. So if it don't detect illumination, the LEDs will turn on.

LDR

High brightness LED (White) are used on this project

The LEDs when the LDR don't detect illumination

the LDR connection to Arduino:

Click on image for a better view.

LDR connection.

Programming

Now, let's go to the best part of the project: Programming.

We start including the libraries:

Including libraries

2º step: Creating variables

Creating variables

3º step: Configurating our sketch

Configuration

4º step: programming the face and the lights

Programming the face and the lights (Click on image to a better view)

Now our LCD bot is finished. lights working, face moving and PIR sensor detecting movement. Have fun with your LCD bot!

Code

Project code

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Ultrasonic.h>
LiquidCrystal_I2C lcd (0x27, 16, 2); //Creating lcd object
Ultrasonic ultrasonic1 (13, 12); //Creating ultrasonic1 object
Ultrasonic ultrasonic2 (11, 10); //Creating ultrasonic2 object
int val1; //variable to store the right Ultrasonic sensor reading values
int val2; //variable to store the left Ultrasonic sensor reading values
int sensor = 2; //PIR sensor attached to digital pin 2
int ldr = A0; //LDR attached to analog pin 0
int ldrvalue = 0; //variable to store the LDR reading values
int led = 3; //1º LED attached to digital pin 3
int led1 = 4; //2º LED attached to digital pin 4
void setup() {
  lcd.init(); //initialize the Display
  pinMode(sensor, INPUT); //sensor defined as input
  pinMode(led, OUTPUT); //1º LED defined as output
  pinMode(led1, OUTPUT); //2º LED defined as output
  pinMode(ldr, INPUT); //LDR defined as input
}

void loop() {
  val1 = ultrasonic1.Ranging(CM); //storing ultrasonic1 reading values in val1
  val2 = ultrasonic2.Ranging(CM); //storing ultrasonic2 reading values in val2
  ldrvalue = analogRead(ldr); //storing LDR reading values in ldrvalue
  if (digitalRead(sensor) == HIGH) { //if PIR sensor detects movement, turns on the Display backlight
    lcd.setBacklight(HIGH);
  }
  else { //if not, turns off the backlight 
    lcd.setBacklight(LOW);
  }
  if (ldrvalue < 300) { //if LDR don't detect luminosity, turn the LEDs on
    digitalWrite(led, HIGH);
    digitalWrite(led1, HIGH);
  }
  else { //if not, turn the LEDs off
    digitalWrite(led, LOW);
    digitalWrite(led1, LOW);
  } 
  if (val1 < 20) { //if the right ultrasonic sensor detects proximity, the face eyes go to right
    lcd.clear();
    lcd.print("O");
    lcd.setCursor(9, 0);
    lcd.print("O");
    lcd.setCursor(6, 1);
    lcd.print("____"); //the mouth
    delay(50);
  }
  else if (val2 < 20) { //if the left ultrasonic sensor detects proximity, the face eyes go to left
    lcd.clear();
    lcd.setCursor(6, 0);
    lcd.print("O");
    lcd.setCursor(15, 0);
    lcd.print("O");
    lcd.setCursor(6, 1);
    lcd.print("____");
    delay(50);
  }
  else { //else, the face don't move 
    lcd.clear();
    lcd.setCursor(3, 0);
    lcd.print("O");
    lcd.setCursor(12, 0);
    lcd.print("O");
    lcd.setCursor(6, 1);
    lcd.print("____");
    delay(50);
  }
}

Credits

bruno_opaiva

6 projects • 4 followers

LCD reactive bot

Things used in this project

Hardware components

Software apps and online services

Story

Installing some Libraries

The Idea

Programming

Schematics

Schematic

Code

Project code

Credits

bruno_opaiva

Comments

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LCD reactive bot

LCD reactive bot

Things used in this project

Hardware components

Software apps and online services

Story

Installing some Libraries

The Idea

Programming

Schematics

Schematic

Code

Project code

Credits

bruno_opaiva

Comments

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