Chapter 6. A Robot that Can Sail

You've built robots that can navigate on land; now let's look at some amazingly cool possibilities for utilizing the tools to build some robots that dazzle the imagination. You don't want to limit your robotic possibilities to just walking or rolling. You might want your robot to sail. In this chapter, you'll see how to build a robot that can sail the open sea, or at least your local park's pond.

In this chapter, you will build the basic sailing platform. To do this, you will learn the following:

• Using the BeagleBone Black to control servos directly

• Communicating with your platform via long range RF signals so that you can retain control of your robotic sailboat

The BeagleBone Black and robots that can sail

Now that you've discovered that the BeagleBone Black can guide platforms that can move on land, let's turn to a completely different type of mobile platform, one that can sail. In this section, you'll discover how to add the BeagleBone Black to a sailing platform and utilize it to control your sailboat.

Building the sailboat platform

Fortunately, sailing in water is about as simple as walking on land. First, however, you need a sailing platform. Here is an image of an RC sailing platform that can be modified to accept control from the BeagleBone Black:

In fact, many RC controller boats can be modified to add the BeagleBone Black. All you need is space to put the processor, the battery, and any additional control circuitry that you might need. In this case, the sailing platform has basically two controls: a rudder that is controlled by a servo and a second servo that controls the position of the sail. These are shown here:

You'll use your BeagleBone...

Remote control of the sailboat

To sail the boat, you'll want to be able to send it commands from quite a distance. One possible solution is wireless LAN. Unfortunately, most lakes or ponds won't have an open wireless network available. You could create your own WLAN access point, but the range will still be somewhat limited. The best possible solution is to use ZigBee wireless devices to connect your sailboat to a computer.

A ZigBee tutorial

The ZigBee standard is built upon the IEEE 802.15.4 standard, a standard that was created to allow a set of devices to communicate with each other to enable low data rate coordination of multiple devices. The ZigBee part of the standard ensures interoperability between vendors of these low-rate devices. The IEEE 802.15.4 part of the standard specifies the physical interface and the ZigBee part of the standard defines the network and applications interface. Since we are only interested in the physical interface working together, you can buy IEEE 802.15...

Summary

After completing this chapter, you should have a working sailboat where your BeagleBone Black can control the two servos to control the positions of the rudder and the sail. You should also be able to do this remotely at quite a distance using your XBee devices.

In the next chapter, you'll add a GPS device to your sailing platform. That way, you will not only know where you are but can also plan your bearing so that you can sail in an automated way to a new waypoint.