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)

Slider

The Slider widget allows you to send a specific range of values from your Blynk app to the hardware (Raspberry Pi). It is analogous to a potentiometer in electronics. The default value of the Slider widget provides a value range of 0 to 255. As examples, sliders can be used to control the brightness of an LED or to control a servo motor.

In this example project, you will control the brightness of an LED attached to the Raspberry Pi BCM_GPIO pin 18, which is a Pulse Width Modulation (PWM) pin.

Brightness can be changed by analog or PWM. With analog, you can control the brightness by simply adjusting the DC current in the wire. But with PWM, you can change the brightness by varying the duty cycle of a constant current in the wire. Therefore, PWM can be implemented on any digital pin without using a potentiometer to control the current flow. PWM is the most appropriate method...