Book Image

Hands-On Internet of Things with Blynk

By : Pradeeka Seneviratne
Book Image

Hands-On Internet of Things with Blynk

By: Pradeeka Seneviratne

Overview of this book

Blynk, known as the most user-friendly IoT platform, provides a way to build mobile applications in minutes. With the Blynk drag-n-drop mobile app builder, anyone can build amazing IoT applications with minimal resources and effort, on hardware ranging from prototyping platforms such as Arduino and Raspberry Pi 3 to industrial-grade ESP8266, Intel, Sierra Wireless, Particle, Texas Instruments, and a few others. This book uses Raspberry Pi as the main hardware platform and C/C++ to write sketches to build projects. The first part of this book shows how to set up a development environment with various hardware combinations and required software. Then you will build your first IoT application with Blynk using various hardware combinations and connectivity types such as Ethernet and Wi-Fi. Then you'll use and configure various widgets (control, display, notification, interface, time input, and some advanced widgets) with Blynk App Builder to build applications. Towards the end, you will learn how to connect with and use built-in sensors on Android and iOS mobile devices. Finally you will learn how to build a robot that can be controlled with a Blynk app through the Blynk cloud and personal server. By the end of this book, you will have hands-on experience building IoT applications using Blynk.
Table of Contents (10 chapters)

Modifying the main.cpp file

To complete your application, the main.cpp file should also be modified to process the data on the virtual pin. These steps show you how to modify it with the nano editor:

  1. Open the main.cpp file with nano by issuing the following command:
pi@raspberrypi:~/blynk-library/linux $ sudonanomain.cpp
main.cpp opened with nano editor
  1. Before using the WiringPi GPIO library, you need to include its header file in your program as follows:
#include <wiringPi.h>
  1. Scroll down to the file with the arrow keys on your keyboard and add the following code to the setup() function:
void setup()
Blynk.begin(auth, serv, port);
pinMode(1, OUTPUT);

The pinMode() function allows you to set the mode of a pin to either INPUT, OUTPUT, or PWM_OUTPUT. Note that only WiringPi pin 1 (BCM_GPIO 18) supports PWM output.

  1. Then, add the following lines to the BLYNK_WRITE(V1...