MANE 3351

Lecture 5

Classroom Management

Agenda

• Arduinos
• Reminder: Lab One - due 9/17 before 9:30 AM
• There will be a short laboratory session following the lecture

---

Resources

Handouts

• Lecture 5 Slides
• Lecture 5 Marked Slides

Assignments

• Lab 2 (assigned 9/17/2025, due 9/24/2024 (before 9:30 AM))

---

Arduino Uno

Source: Arduino Uno Website

---

Source: Arduino Website

---

Input/Output

• Voltages - 5V pin and 9V pin are present on the board as well as ground pins (0v)
• Digital Pins - multiple digital pins are provided on an Arduino board that can be used for general purpose input and output via the pinMode(), digitalRead(), and digitalWrite() commands
• Analog Pins- the analog input pins suport 10-bit analog-to-digital conversion using the analogRead() function
• Other Pins - A reference voltage and reset functionality are also available

---

Arduino Mega

• There are multiple versions of Arduino boards.
• The Arduino Mega is often combined with a RAMPS shield to construct homemade Reprap 3D-printers

Source: all3dp

---

RAMPS Shield

• Circuit board that plugs into Arduino Mega for build 3D printers
• Typically includes drivers for stepper motors shown below
• Schematic for 3D printer is also provided below
• Both images taken from All3DP website

---

---

Programming Arduino

• Written in the Arduino Integrated Development Environment
• Arduino programming language is based on a very simple hardware programming language called processing, which is similar to the C language
• Programs for Arduinos are called sketches
• Sketches must be uploaded to Arduino (via USB cable)
• Arduino IDE installed on Raspberry Pi

Source: Programming Arduinos

---

Example 1: Blinking an LED

• First example is to an LED (same as with the Raspberry Pi)

---

Example 1: Sketch

• Note: there is an error in the sketch. Change digitalRead to digitalWrite

---

Code for Blinking an LED

int LED = 13; // the digital pin to which the LED is connected

void setup ()
{
pinMode (LED,OUTPUT); //Declaring pin 13 as output ping
}

void loop () //The loop function runs again and again
{
digitalWrite (LED,HIGH); //Turn ON the LED
delay (1000); //wait for 1 second
digitalWrite(LED,LOw); //Turn OFF the LED
delay(1000); //wait for one second
}

---

Warning

• Arduinos store the last program in EEPROM and will start running that program as soon as the power is provided
• Cautious Approach:
  • Do not connect circuit board to Arduino until after the Sketch is loaded
  • Afterwards, connect hardware

---

Arduino Demonstration 1

---

DHT22 Sensor

Source:

---

Technical Details of DHT11 Sensor

Source:

---

Arduino Circuit

Source:

---

Arduino Sketch

Source: Example Code

---

Arduino Sketch, continued

Source: Example Code

---

DHT Library

Source:

---

DHTest Code

// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain

// REQUIRES the following Arduino libraries:
// - DHT Sensor Library: https://github.com/adafruit/DHT-sensor-library
// - Adafruit Unified Sensor Lib: https://github.com/adafruit/Adafruit_Sensor

#include "DHT.h"

#define DHTPIN 2     // Digital pin connected to the DHT sensor
// Feather HUZZAH ESP8266 note: use pins 3, 4, 5, 12, 13 or 14 --
// Pin 15 can work but DHT must be disconnected during program upload.

// Uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
//#define DHTTYPE DHT21   // DHT 21 (AM2301)

// Connect pin 1 (on the left) of the sensor to +5V
// NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1
// to 3.3V instead of 5V!
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 3 (on the right) of the sensor to GROUND (if your sensor has 3 pins)
// Connect pin 4 (on the right) of the sensor to GROUND and leave the pin 3 EMPTY (if your sensor has 4 pins)
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor

// Initialize DHT sensor.
// Note that older versions of this library took an optional third parameter to
// tweak the timings for faster processors.  This parameter is no longer needed
// as the current DHT reading algorithm adjusts itself to work on faster procs.
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  Serial.println(F("DHTxx test!"));

  dht.begin();
}

void loop() {
  // Wait a few seconds between measurements.
  delay(2000);

  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }

  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);

  Serial.print(F("Humidity: "));
  Serial.print(h);
  Serial.print(F("%  Temperature: "));
  Serial.print(t);
  Serial.print(F("°C "));
  Serial.print(f);
  Serial.print(F("°F  Heat index: "));
  Serial.print(hic);
  Serial.print(F("°C "));
  Serial.print(hif);
  Serial.println(F("°F"));
}

---

Demonstration 2 - Temperature/Humidity Sensor