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)

Using virtual pins

Now you know how to write the current state of the Button widget to a GPIO pin.

With virtual pins, you can send or receive any type of data between the microcontroller (Raspberry Pi) and the Blynk app. The Blynk app builder provides 128 virtual pins for working with Raspberry Pi. They allow you to interface with sensors, actuators, and libraries. These pins have no physical properties. Some Blynk widgets support virtual pins, some do not.

As an example, you can write the current state of the Button widget to the virtual pin V1 as shown here. Then, you can assign the incoming value from the virtual pin to a variable for further processing:



intpinValue = param.asInt(); // assigning value on Virtual Pin (V1) to a variable

// process received value