|By Kaazing Blog||
|April 1, 2013 03:31 AM EDT||
At Kaazing, we have been experimenting with using a smartphone as a remote control for quite some time now. Those familiar with our demos may have seen our Zing-Pong demo (which is a “Pong”-style game using smartphones to control the paddles over WebSocket) or our Racer demo (which is a 3D Formula One car rendered in WebGL as a Chrome Experiment, and remotely controlled with a smartphone). These demos, along with the other demos we’ve created with Kaazing’s platform, use no plug-ins. You simply point a browser on your computer to the address of the object you want to control (for example, the gorgeous Formula One car rendered in WebGL) and a browser from your smartphone to the address of the remote control (an ID we generate for you). Once connected, you just…go!
A couple of our Visionary Zingers, Prashant Khanal and David Witherspoon, then experimented with communicating with a Raspberry Pi using WebSocket–or, more specifically, using Kaazing’s JMS-over-WebSocket Gateway to tell Raspberry Pi to turn on and off a lightbulb. When the lightbulb turned on in this experiment, another lightbulb turned on: could we in fact turn a remote, radio-controlled car into a remote, WebSocket-controlled car? By controlling the car over the Web, could we control the car from another room? From another continent?
The Racer Demo
Let’s first take a closer look at the Racer demo. The Racer demo uses the reflector pattern: where we connect devices through a WebSocket server, thus simulating peer-to-peer connectivity, a very easy-to-achieve task using pub/sub. When we developed the Racer demo, we walked through the steps to build it in The Simplest Way to Use Your Smartphone as a Game Controller: A WebSocket Race Car Demo. By examining how to use pub/sub concepts to control a virtual car, it’s not so farfetched to consider doing the same with a radio-controlled car.
After working with the Racer demo, we knew what we wanted to achieve: controlling a “real” car (or at least a good-sized monster truck model) with a simple web app on a smartphone. Something like this, for example:
And something that might move like this:
In just a few hours of hacking and experimenting, we turned this radio-controlled car into a WebSocket-controlled car. Don’t worry, no actual cars (or bunnies) were harmed in the making of this demo, as you’ll see as we walk through the hardware and software we used.
Ingredients: The Hardware
- One RC car. We ended up using a black F150. The bigger the car, the easier it is to connect, position, and hide the building blocks. One thing to pay attention to is that the car you’re about to buy has to have two simple motors, one that drives the vehicle forward/backward, and another one that steers the car: front wheels left/right. The first thing you’ll get rid of is the radio control, so don’t worry about that too much.
- One Raspberry Pi, model B. This piece of hardware is incredible. Runs Linux (and Java), has 512MB RAM, an Ethernet port, 2 USB ports (for keyboard, mouse, WiFi), takes an SD card, has an HDMI out, and has a handful of GPIO (General Purpose Input/Output) pins to drive external devices, like lights, motors, and alike.
- One small breadboard. This simplifies connecting the building blocks.
- Set of male to male and male to female jumper leads.
- L298N Board: It is used to control the car motors. The car is equipped with two motors – one for steering and the other to drive wheels. Each motor is controlled through two GPIO pins.
- A couple of LEDs – optional. This RC car model didn’t come with any lights, but who has seen a serious RC car without lights – so we equipped ours with remote controllable LEDs.
- One smartphone (can be substituted by a tablet, or any Web browser, really). Using a touch-based device makes the controlling more natural, but you can use any laptop/desktop browser with mouse/trackpad as well.
- Battery. Anker Astro 5600 mAh external battery pack powering the Raspberry Pi and connected circuits: LEDs and relays.
The circuit diagram regarding the wiring among the Raspberry Pi GPIO pins, L298N board and the car battery can be found here. The pin numbers specified for the Raspberry Pi in the circuit diagram refers to the physical pin location.
Ingredients: The Software
- WebSocket Java client code. The Kaazing Java client runs on the Raspberry Pi, receiving messages from the WebSocket server, and instructing the Raspberry Pi GPIO pins to control the car. Control of the GPIO pins is achieved through the Pi4J Library.
Reviewing the Hardware
We decided to hide all the electronics in the body of the car, but wanted to have the Raspberry Pi accessible and more importantly, visible. It’s sitting on the truck’s plateau, lightly taped to it, so it doesn’t fall off as the truck accelerates and comes to sudden stops (read: bumps into things).
On the right you can see the WiFi plugged into the top USB port (blue LED). On the left, you see the blue SD card. The GPIO ports are on the top left, connected to drive the two motors and the lights of the truck. The Raspberry Pi is powered through a micro USB port on the bottom left, leveraging a smartphone quick charger battery.
Reviewing the Software
To enable the Raspberry Pi to receive WebSocket messages from the browser client, we had to write some logic that runs on the Pi.
Since we plan to use this demo at trade shows, we wanted to make sure that we have a certain level of control over who controls the car and when. Therefore, we use a “secret” key that the remote control has to know to control the car. This key is sent to the code running on the Pi via a secured admin topic. Every message coming from the smartphone has to contain the same key. If it doesn’t, the message is thrown away.
The remote control client on the smartphone first asks for the key that identifies who can control the car.
Then, the HTML5 remote control code, which runs on the smartphone, first establishes a connection to the WebSocket server. It creates a JMS topic, and a producer (or publisher) for the topic. When done, the client is ready to start sending messages through the WebSocket gateway to the Java code running on the Pi. Every message contains the previously specified key as well, as a custom JMS message property.
Java Code Running on the Raspberry Pi
We chose to program the Raspberry Pi using Java. Instructions to install Java on the Raspberry Pi can be found here. The Java code on the raspberry requires both the JMS Kaazing Websocket Library to receive messages from the client, and the Pi4J library to interact with the car through the Rasbperry Pi’s GPIO .
The code is split into two main classes, CommandReceiver and Car. CommandReceiver is responsible for connecting to the Kaazing JMS Gateway and listening to both on the command and the admin topic. When admin messages are received the CommandReceiver will record which user has valid access to control the car. When a command message is received, its properties will be checked to see if it is the current user in control of the car. If so, the message will be parsed and read, resulting in a corresponding method being called on the Car class.
The Car class is an abstraction of everything the car may do. It has methods such as Steering, Thrust, and Lights that are called with Command parameters such as ON, OFF, LEFT, and RIGHT. When called, the GPIO inputs corresponding to each method and are switched on or off, thereby resulting on the motors of the car moving forward, backwards, or steering left or right.
To check out or download the full source code visit KaazingPi on Github.
Well, we cheated and already showed the video of the result at the beginning. But, if you want to see it in person, come see us at one of our upcoming events:
- HTML5DevConf: 1-2 April 2013. Palace Hotel, San Francisco
- NABSHOW: 6-11 April 2013. Las Vegas Convention Center, Las Vegas
- SIFMA Tech: 18-19 June 2013. Hilton New York, New York
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - comp...
Aug. 29, 2016 02:15 PM EDT Reads: 3,727
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long dev...
Aug. 29, 2016 02:00 PM EDT Reads: 2,474
Almost two-thirds of companies either have or soon will have IoT as the backbone of their business in 2016. However, IoT is far more complex than most firms expected. How can you not get trapped in the pitfalls? In his session at @ThingsExpo, Tony Shan, a renowned visionary and thought leader, will introduce a holistic method of IoTification, which is the process of IoTifying the existing technology and business models to adopt and leverage IoT. He will drill down to the components in this fra...
Aug. 29, 2016 01:01 PM EDT Reads: 200
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, will discuss the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
Aug. 29, 2016 12:45 PM EDT Reads: 2,017
There is growing need for data-driven applications and the need for digital platforms to build these apps. In his session at 19th Cloud Expo, Muddu Sudhakar, VP and GM of Security & IoT at Splunk, will cover different PaaS solutions and Big Data platforms that are available to build applications. In addition, AI and machine learning are creating new requirements that developers need in the building of next-gen apps. The next-generation digital platforms have some of the past platform needs a...
Aug. 29, 2016 12:15 PM EDT Reads: 814
19th Cloud Expo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterpri...
Aug. 29, 2016 12:00 PM EDT Reads: 3,185
SYS-CON Events announced today Telecom Reseller has been named “Media Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
Aug. 29, 2016 08:00 AM EDT Reads: 938
Pulzze Systems was happy to participate in such a premier event and thankful to be receiving the winning investment and global network support from G-Startup Worldwide. It is an exciting time for Pulzze to showcase the effectiveness of innovative technologies and enable them to make the world smarter and better. The reputable contest is held to identify promising startups around the globe that are assured to change the world through their innovative products and disruptive technologies. There w...
Aug. 29, 2016 07:30 AM EDT Reads: 818
With so much going on in this space you could be forgiven for thinking you were always working with yesterday’s technologies. So much change, so quickly. What do you do if you have to build a solution from the ground up that is expected to live in the field for at least 5-10 years? This is the challenge we faced when we looked to refresh our existing 10-year-old custom hardware stack to measure the fullness of trash cans and compactors.
Aug. 29, 2016 02:15 AM EDT Reads: 1,837
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions wi...
Aug. 29, 2016 01:45 AM EDT Reads: 2,201
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
Aug. 29, 2016 01:15 AM EDT Reads: 3,031
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
Aug. 29, 2016 12:00 AM EDT Reads: 1,919
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
Aug. 28, 2016 10:30 PM EDT Reads: 4,076
Smart Cities are here to stay, but for their promise to be delivered, the data they produce must not be put in new siloes. In his session at @ThingsExpo, Mathias Herberts, Co-founder and CTO of Cityzen Data, will deep dive into best practices that will ensure a successful smart city journey.
Aug. 28, 2016 06:30 PM EDT Reads: 1,652
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
Aug. 28, 2016 06:00 PM EDT Reads: 1,969
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
Aug. 27, 2016 08:45 PM EDT Reads: 2,428
I wanted to gather all of my Internet of Things (IOT) blogs into a single blog (that I could later use with my University of San Francisco (USF) Big Data “MBA” course). However as I started to pull these blogs together, I realized that my IOT discussion lacked a vision; it lacked an end point towards which an organization could drive their IOT envisioning, proof of value, app dev, data engineering and data science efforts. And I think that the IOT end point is really quite simple…
Aug. 27, 2016 12:45 PM EDT Reads: 2,402
Personalization has long been the holy grail of marketing. Simply stated, communicate the most relevant offer to the right person and you will increase sales. To achieve this, you must understand the individual. Consequently, digital marketers developed many ways to gather and leverage customer information to deliver targeted experiences. In his session at @ThingsExpo, Lou Casal, Founder and Principal Consultant at Practicala, discussed how the Internet of Things (IoT) has accelerated our abil...
Aug. 27, 2016 02:30 AM EDT Reads: 2,093
Is the ongoing quest for agility in the data center forcing you to evaluate how to be a part of infrastructure automation efforts? As organizations evolve toward bimodal IT operations, they are embracing new service delivery models and leveraging virtualization to increase infrastructure agility. Therefore, the network must evolve in parallel to become equally agile. Read this essential piece of Gartner research for recommendations on achieving greater agility.
Aug. 25, 2016 05:15 PM EDT Reads: 922
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
Aug. 25, 2016 01:00 PM EDT Reads: 2,730