Book Image

Hands-On Internet of Things with MQTT

By : Tim Pulver
Book Image

Hands-On Internet of Things with MQTT

By: Tim Pulver

Overview of this book

MQ Telemetry Transport (MQTT) is a lightweight messaging protocol for smart devices that can be used to build exciting, highly scalable Internet of Things (IoT) projects. This book will get you started with a quick introduction to the concepts of IoT and MQTT and explain how the latter can help you build your own internet-connected prototypes. As you advance, you’ll gain insights into how microcontrollers communicate, and you'll get to grips with the different messaging protocols and techniques involved. Once you are well-versed with the essential concepts, you’ll be able to put what you’ve learned into practice by building three projects from scratch, including an automatic pet food dispenser and a smart e-ink to-do display. You’ll also discover how to present your own prototypes professionally. In addition to this, you'll learn how to use technologies from third-party web service providers, along with other rapid prototyping technologies, such as laser cutting, 3D printing, and PCB production. By the end of this book, you’ll have gained hands-on experience in using MQTT to build your own IoT prototypes.
Table of Contents (16 chapters)
Title Page

Controlling the servo motor via the Serial Monitor

In the previous section, we verified the following:

  • Whether the Arduino can connect to the internet
  • Whether the Arduino can send and receive MQTT messages via shiftr.io
  • Whether the motor is working

Now, let's create an interface to control the servo from the Serial Monitor. Create a new sketch and save it as ch5_01_servo_serial.

Delete the boilerplate code that is automatically added to new sketches (the empty setup and loop functions) and replace the contents of your editor with the following code:

#include <Servo.h>

Servo myservo;

void setup() {
Serial.begin(9600);
myservo.attach(9);
}

void loop() {
while (Serial.available() > 0) {
int inputValue = Serial.parseInt();
if (inputValue == 1) {
myservo.write(180);
} else {
myservo.write(0);
}
}
}

Let's go through the code to make sure...