Tag: Arduino

Arduino LCD Displays

Wire up the arduino using these following instructions

• VCC (Red) to 5V
• Ground/GND (Black) to GND
• SDA (Blue) to A4
• SCL (Yellow) to A5

The code used was downloaded adn the library installed in the specific location. Ensure that the LCD drivers are included in the same folder

#include <Wire.h>  // Comes with Arduino IDE
// Get the LCD I2C Library here: 
// https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads

#include <LiquidCrystal_I2C.h>

// set the LCD address to 0x27 for a 20 chars 4 line display
// Set the pins on the I2C chip used for LCD connections:
//                    addr, en,rw,rs,d4,d5,d6,d7,bl,blpol
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);  // Set the LCD I2C address

void setup()   /*----( SETUP: RUNS ONCE )----*/
{
  Serial.begin(9600);  // Used to type in characters
  lcd.begin(20,4);         // initialize the lcd for 20 chars 4 lines, turn on backlight

  //-------- Write characters on the display ------------------
  // NOTE: Cursor Position: Lines and Characters start at 0  
  // lcd.setCursor(Horizontal position,Line) 
  
  lcd.setCursor(4,0); //Start at character 4 on line 0
  lcd.print("GO BACK");
  lcd.setCursor(4,1);  //Next start at character 6 on line 1
  lcd.print("TO");
  delay(1000);
  lcd.setCursor(4,2);
  lcd.print("THE");
  delay(1000);  
  lcd.setCursor(4,3);
  lcd.print("SHADOWS");
  
  delay(4000);
  // Wait and then tell user they can start the Serial Monitor and type in characters to
  // Display. (Set Serial Monitor option to "No Line Ending")
  lcd.setCursor(0,0); //Start at character 0 on line 0

  lcd.clear(); //Clears the screen.
  lcd.print("Start Serial Monitor");
  lcd.setCursor(0,1);
  lcd.print("Type characters");  
  lcd.setCursor(0,2);
  lcd.print("to display");  


}/*--(end setup )---*/


void loop()   /*----( LOOP: RUNS CONSTANTLY )----*/
{
  {
    // when characters arrive over the serial port...
    if (Serial.available()) {
      // wait a bit for the entire message to arrive
      delay(100);
      // clear the screen
      lcd.clear();
      // read all the available characters
      while (Serial.available() > 0) {
        // display each character to the LCD
        lcd.write(Serial.read());
      }
    }
  }

}/* --(end main loop )-- */

Displaying ultrasonic measurements on LCD screen

This is the code for running the screen and the ultrasound sensor all as the same time, displaying the range in cm to the LCD screen attached to the the arduino

It is a combination of both the ultrasonic sketch downloaded from student central and the above LCD sketch. The basics behind it is setting up the ultrasonic sensor as an input and keeping the LCD as an output

After some playing around to change the refresh rate (delay) of the LCD and where the stationary text was it looked good and could accurately read the distance if it was within its range

#include <Wire.h> // Comes with Arduino IDE
// Get the LCD I2C Library here:
// https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads

#include <LiquidCrystal_I2C.h>

// set the LCD address to 0x27 for a 20 chars 4 line display
// Set the pins on the I2C chip used for LCD connections:
// addr, en,rw,rs,d4,d5,d6,d7,bl,blpol
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); // Set the LCD I2C address

#define echoPin 7 // Echo Pin
#define trigPin 8 // Trigger Pin
#define LEDPin 13 // Onboard LED

int maximumRange = 200; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration;
long distance; // Duration used to calculate distance

void setup() {
Serial.begin(9600);
lcd.begin(20,4);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(LEDPin, OUTPUT);

lcd.setCursor(0,0);
lcd.print("Range Finder");
lcd.setCursor(0,1);
lcd.print("Current Distance : ");
lcd.setCursor(7,2);
lcd.print("cm");

}

void loop() {
/* The following trigPin/echoPin cycle is used to determine the
distance of the nearest object by bouncing soundwaves off of it. */
digitalWrite(trigPin, LOW);
delayMicroseconds(2);

digitalWrite(trigPin, HIGH);
delayMicroseconds(10);

digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH); // Measures the length of a pulse on echoPin in microseconds
//waits for the pin to go HIGH, starts timing, then waits for the pin to go LOW and stops timing.
//Returns the length of the pulse in microseconds.

//Calculate the distance (in cm) based on the speed of sound.
distance = duration/58.2;

if (distance >= maximumRange || distance <= minimumRange){

lcd.clear();
lcd.setCursor(0,0);
lcd.print("Range Finder");
lcd.setCursor(0,1);
lcd.print("Current Distance : ");
lcd.setCursor(4,2);
lcd.print(distance);
lcd.setCursor(7,2);
lcd.print("cm");
delay(300);
digitalWrite(LEDPin, HIGH);

}
else {
lcd.clear();
lcd.setCursor(0,0);
lcd.print("Range Finder");
lcd.setCursor(0,1);
lcd.print("Current Distance : ");
lcd.setCursor(4,2);
lcd.print(distance);
lcd.setCursor(7,2);
lcd.print("cm");
delay(300);
digitalWrite(LEDPin, LOW);
}
delay(500);
}

What is a stepper motor?

A stepper motor uses opposing electromagnets to create rotation. The different number of steps are determined by the number of poles on each the stator and the rotor.

There are several different types of stepper motor, depending on the use case and the size that is required. The main types are :

Permanent magnet stepper > These use permanent magnets in the rotor and electromagnets in the rotor, using attraction and repulsion to create rotation

Uses

Stepper motors can be used for all sorts of CNC controlled devices such as 3D printer or CNC routers.

Mechanical arms such as those used for assembly of cars etc will use stepper motors to obtain exact position repeatably

Any automated machinery that requires exact positions to be returned to, will use stepper motor as they are very precise int he increments of rotation that they can do.

How to drive a stepper motor

Wave forms that drive a stepper motor

Turning coils on and off > Transistors are electric dimmer switches which can be used as on off switches for stepper motors

 

Stepper Motors with Arduino – Getting Started with Stepper Motors

Stepper Motor Code

Setup code for the stepper motor initialises which pins are the outputs from the arduino

void setup() {

// initialize digital pin LED_BUILTIN as an output.

pinMode(13, OUTPUT);

pinMode(12, OUTPUT);

pinMode(11, OUTPUT);

pinMode(10, OUTPUT);

}

void loop() {
//STEP 1
digitalWrite(10, HIGH);
digitalWrite(11, LOW);
digitalWrite(12, LOW);
digitalWrite(13, HIGH);
delay(2);                                      // delay

//STEP 2
digitalWrite(10, HIGH);
digitalWrite(11, HIGH);
digitalWrite(12, LOW);
digitalWrite(13, LOW);
delay(2);                                      // delay

//STEP 3
digitalWrite(10, LOW);
digitalWrite(11, HIGH);
digitalWrite(12, HIGH);
digitalWrite(13, LOW);
delay(2);                                      // delay

//STEP 4
digitalWrite(10, LOW);
digitalWrite(11, LOW);
digitalWrite(12, HIGH);
digitalWrite(13, HIGH);
delay(2);                                     // delay

The loop will run through all of the bracketed coded indefinitely

delay(2) is the amount of ms left between that line of code and the next, which determines how fast or slow the motor will turn. The smaller the number, the faster it spins.