A robot via the Web to perform some activity

Radio control of a robot is one thing, but what if we built a robot that connects to the Web, so we could control it from around the world? It doesn’t get much cooler than that!

Chapter 7, “Harnessing Infrared,” in my book Robot Builder: The Beginner’s Guide to Building Robots shows how to build an Arduino-equipped dart gun that detects intruders with a passive infrared (PIR) sensor and blasts them with a foam dart. In this tutorial, I’ll show you how to give the dart gun (shown in Figure 1) the ability to send you a message via Simple Notification Service (SNS) whenever the gun fires. Talk about intruder detection!


Types of Web-Interacting Robots

What exactly can you do with a web-connected robot? As it turns out, quite a lot! This section covers some of the possibilities.



Sniffer robots search the Internet collecting keywords, and then their programming does something with that collected information. For example, some gumball machines dispense only if a certain keyword appears on Twitter. Some organizations have an LCD screen scrolling with recent keyword mentions.

One advantage of a sniffer system is that it can be controlled remotely with no need for additional hardware—merely a Twitter account. The downside is exactly the same—in that anyone can hijack your robot.



Autotweeter robots send out a Twitter message (tweet) when certain events take place. The classic example is a kegbot that monitors and controls a beer keg. It dispenses beer and measures its temperature, accepts payment, and sends out a tweet when the keg pours a pint.

Recently Twitter changed the way it interacts with external devices, and some old methods of sending out tweets no longer work. However, as long as Twitter continues to be popular, there will be a way to interact with it.



As an introvert, I always dreamed of a robot that could go to family functions and school dances in my stead. I could sit back and direct the robot to roll around, with a camera and screen allowing me to interact with guests. One category of robots actually does that—telepresence bots.

At its simplest, a telepresence robot rolls around carrying an iPad or other tablet, with videoconferencing running on the computer. The home base could include a desktop PC that controls the robot remotely. Some clever hacks have piggybacked the control functionality on top of the videoconferencing feed—one bot creator used black-and-white cards to trigger a light sensor positioned at the corner of the screen.



Some robots, like the gumball machine I mentioned in the sniffer section, are designed to be controlled remotely. Robot arms can be directed from websites, with webcams positioned to show what’s happening. A whole subcategory involves pet toys that let you play with your cat or dog from a remote location.

Some interactive bots are games, such as chessboards with players separated by miles; others are much simpler, the equivalent of robot soccer. Typically interactive robots (like a lot of robots I’ve described here) are designed for fun rather than to accomplish a serious task, but it doesn’t have to be that way!


Home Automation

One category of serious web-connected robots is for home automation. Imagine being able to adjust your window blinds with your smartphone, or having a program that varies lighting schemes when you’re on vacation. These robots can send you data on the status of your alarm system, tell you whether your home’s furnace is running, and more.

This category also includes agricultural automation such as greenhouse controllers, which turn on fans and trigger water valves, measure temperature and soil moisture, and turn on grow lights as needed.


Sensor Net

One of the most intriguing aspects of all these devices connected across the Net is the possibility that you could have all of them measure the same thing and publish that data to the Web, giving you a real-time map of an area.