Arduino Basics: Serial Monitor

Let's explore a useful tool of Arduino the Serial Monitor. We often need it to test our code.

BeginnerFull instructions provided3 hours735

Things used in this project

Hardware components

Arduino Nano R3

SparkFun Pushbutton switch 12mm

Resistor 10k ohm

Breadboard (generic)

Jumper wires (generic)

Software apps and online services

Arduino IDE

Story

Let's learn to read data directly from the Arduino as text.

Open up File > Examples > Basics > DigitalReadSerial, and set up your button as the picture below. Upload the sketch to your board.

Figure 1

1 / 2 • Button circuit with pulldown resistor

CODE

Things should be looking much familiar by now. The news is about the serial monitor:

In setup(), look for Serial.begin(9600); which tells the Arduino to start communicating via text, at 9600 baud. The baud rate controls how much information is sent per second.

And in the loop(), you'll see the command Serial.println(buttonState);, this tells the Arduino to take the current value of the button and print it to the monitor as a single line of text.

The monitor itself can be opened with the button at the top-right of the IDE:

Figure 2

Open it up, and you'll start to see a column of 0s. Push your button, and they will turn into 1s. If you set it free you will see 0s. Cool?

Figure 3

If you don't see the pretty 1s and 0s, check the settings at the bottom of the window:

Autoscroll should be selected
Newline should be selected
9600 baud should be selected (the rate at which the monitor expects to receive data)

Let's go deeper

What else can we do?

Get real-time readings from a sensor (MAIN FUNCTION)
Embed debug messages in code: Print to the serial monitor at crucial points in execution, to help with troubleshooting

Code

Arduino example DigitalReadSerial

/*
  DigitalReadSerial
 Reads a digital input on pin 2, prints the result to the serial monitor

 This example code is in the public domain.
 */

// digital pin 2 has a pushbutton attached to it. Give it a name:
int pushButton = 2;

// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
  // make the pushbutton's pin an input:
  pinMode(pushButton, INPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input pin:
  int buttonState = digitalRead(pushButton);
  // print out the state of the button:
  Serial.println(buttonState);
  delay(1);        // delay in between reads for stability
}

Credits

Iasonas Christoulakis

9 projects • 31 followers

Biomedical Engineer MedispLab Instructor Former General Manager at IEEE NTUA Student Branch

Arduino Basics: Serial Monitor