My Ardunio Hello world - 3 LED's and a Potentiometer

This morning I jumped out of bed at 7am (like at 9 year old boy), brewed a coffee (like a middle-aged man) and set about playing with my new Arduino (like a 9 year old boy). After flying through a few basic tutorials, I was ready to go it alone and try building something off my own back.

This isn't strictly an Internet of Things project but just 2 hours into learning about electronics I have made something work, and I'm proud of myself so thought I'd knock out a quick blog post.

What does it do?

I decided I wanted to make a series of LED's represent the resistance across a potentiometer - not exactly groundbreaking but it was a challenge I felt I could achieve before my pot of coffee went cold.

Kit I used on this project:

• 1 x Arduino UNO r3
• 1 x Breadboard
• 1 x Potentiometer
• 3 x coloured LED's
• 3 x 220 Ohm resistors
• A load of hook-up wires
• USB cable (for power and data)
• Laptop
• Offical Arduino IDE
• Limited imagination
• Programing knowledge

Project video

How does it work

I wrote a simple script that does the following:

• Initiates serial comms on startup
• Runs a continuous loop that reads analog input from the Potentiometer sensor
• Checks the sensor value on each pass of the loop
• Turns on the correct LED based on sensor value
• If high value (>1000) run another loop to make the red LED flash

I also created a simple method called clearLEDs() that is called whenever I want all LED's to be switched off.

In pictures

The code

This is a thrown-together script to get something working but hey it works so serves its purpose.

int redPin = 9;  
int greenPin = 10;  
int bluePin = 11;  
int fadeValue = 250;

void setup() {  
  Serial.begin(9600);
}

void loop() {

  int sensorValue = analogRead(A0);  
  Serial.println(sensorValue);

  if (sensorValue < 5){
    clearLEDs();
  }
  else if (sensorValue < 500){
    clearLEDs();
    analogWrite(bluePin, fadeValue);
  }
  else if (sensorValue < 900){
    clearLEDs();
    analogWrite(greenPin, fadeValue);          
  }
  else{
    clearLEDs();
    for (int fadeValue = 0 ; fadeValue <= 255; fadeValue += 5) {   
      analogWrite(redPin, fadeValue);   
      delay(2);
    }
    for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 5) {   
      analogWrite(redPin, fadeValue);   
      delay(5);
    }      
  } 
  delay(100);
}

void clearLEDs() {  
  for (int thisPin = 9; thisPin < 12; thisPin++) {
    analogWrite(thisPin, 0);
  }
}

This is a very simple "Hello World" project but I'm happy with my first ever Arduino project. The best part is I managed to not blow anything up!

Next up is my first real IoT project!