September 2015 Summaries

The text outlines a tutorial for creating a hardware-to-software application that streams air pressure sensor readings to a real-time dashboard using a spline chart. The application consists of two main parts: the server side, which operates on a microcontroller to collect and transmit data, and the client side, which displays the data on a live-updating chart using the EON framework. The server side uses JavaScript with Johnny-Five and PubNub packages to gather sensor data every 100 milliseconds and publish it to a channel, while the client side employs an HTML file with embedded JavaScript to receive data and generate a time-series chart. The tutorial provides step-by-step instructions, including setting up the necessary npm packages, obtaining unique PubNub keys, and configuring the chart's axes and flow, enabling users to visually monitor sensor data in real time.

JavaScript, which has become the most popular web programming language, was initially used for front-end tasks like DOM manipulation and animations, but the advent of NodeJS revolutionized its use by enabling server-side applications. This evolution allowed JavaScript to support microcontrollers and microprocessors, particularly through libraries such as CylonJS and Johnny-Five, known for their compatibility with a range of technologies, ease of use, and strong community support. The text describes a project using the Johnny-Five framework to establish real-time hardware-to-hardware communication between a button and an LED, facilitated by PubNub for internet-based interactions. To implement this, users need to set up a JavaScript file, install necessary npm packages globally, and configure the Johnny-Five and PubNub libraries with unique keys from the PubNub Developer Dashboard. The project involves configuring a board to respond to button presses that trigger LED actions via PubNub channels, showcasing JavaScript's versatility in both client and server environments.

In this blog post, the author details a project that involves connecting a SainSmart ADXL335 Triple Axis Accelerometer to the Internet using an Intel Galileo, and streaming its data in real time to a dashboard. The accelerometer, a small sensor capable of measuring static and dynamic acceleration, is integrated with the Intel Galileo—an IoT prototyping chip running NodeJS—through soldering and wiring. The data from the accelerometer is then published via PubNub, a real-time network service, allowing it to be streamed and visualized on a live-updating HTML dashboard using the EON chart framework. The process includes setting up PubNub as a dependency in Node.js, reading the accelerometer's X, Y, and Z axis data, and rendering this information in a bar chart format on the dashboard. The blog concludes by suggesting potential extensions to the demo, such as incorporating additional sensors or microcontrollers to enhance functionality.

PubNub's new Chat Resource Center provides resources for building and deploying mobile and web chat, and introduces strategies for efficiently managing message retrieval in scenarios with numerous chat channels. Traditional 1-1 chat setups, which require separate channels for each user pair, can become inefficient with many friends, leading to a high volume of history() calls for missed messages. To optimize, the introduction of an Inbound channel for each user allows all incoming messages, regardless of the sender, to be centralized in one channel, much like an email inbox, thereby reducing the number of history calls needed. Additionally, for group chats, large groups can still utilize separate channels to maintain efficiency. A Hybrid pattern, combining Inbound and unique Hybrid channels for each pair of users, enables easier retrieval of chat history, allowing users to access messages from all chats via the Inbound channel while having the option to view specific conversations through the Hybrid channel. This dual-publishing method enhances the ability to manage both new messages and historical conversations effectively.

This tutorial provides a detailed guide to implementing real-time location tracking on a live-updating map using the EON framework and the Mapbox API with JavaScript. It explains how to stream data from a connected user, display their location on a map, and update the marker as the user moves. The tutorial includes steps for setting up Mapbox with EON, using PubNub for data streaming, and customizing markers and map elements. It also discusses using unique PubNub API keys for enhanced security, configuring distributed systems to compile messages from multiple sources, and offers guidance on customizing maps via the Mapbox API and editor. Practical examples, such as tracking multiple devices and publishing messages from different sources, are provided to illustrate the functionality of the system.