How to Make a Line-Following Robot

The virtual wall accessories will make sure your Roomba follows the line dutifully.

A line-following robot can be an enjoyable way to entertain friends and family, as well as a technically impressive proof of concept for the capabilities of domestic robots. While it is possible to build a line-following robot from scratch, a simpler approach is to take advantage of the sensor technology that many commercially available domestic robots come prepackaged with. The iRobot Roomba brand of autonomous home vacuum cleaners is ideal for this application, and can be converted into a line-following robot using no additional third-party hardware.

Things You'll Need

• Roomba autonomous home vacuum cleaner
• 2 Roomba "Virtual Wall" accessories
• 2 additional "Virtual Wall" accessories for each turn you want your line to make
• Painter's tape

Instructions

1. Place painter's tape on the floor in the shape of the line you want your Roomba to follow. Turns in the line are acceptable, but you should keep them to a minimum, since each turn will require you purchase more "Virtual Wall" accessories. All turns should be sharp angles, not curves.

2. Set up "Virtual Wall" accessories on either side of each straight line segment you want your Roomba to follow. Each "Virtual Wall" should run parallel with the line segment and be positioned seven inches out from the line segment. The end result should be a fourteen inch wide angular "path" bracketed by "Virtual Wall" units on both sides for your Roomba to move along.

   (The "Virtual Wall" is a small infrared beam that sensors on the Roomba will react to. It can be discreetly affixed to walls and furniture. The "wall" itself will span the length of the beam.)

3. Place your Roomba at the beginning of the path, with its front facing the desired direction of travel.

4. Turn the Roomba on. Activate the "Clean" routine. The Roomba will now move forward along the path you have outlined, bouncing off the "Virtual Walls" whenever it comes in contact with them, including at turns. This will effectively funnel the Roomba through the room down the desired line.

Tips & Warnings

• Take care that your "Virtual Wall" units remain level with the ground. If they are mounted at an angle, the infrared beam will fail to make contact and the Roomba will go astray.

• Consider adding additional modifications once your line-following Roomba has successfully passed a couple trial runs down the path. For instance, by securely bolting a flat tray to the top of your Roomba, you could create a robot waiter to ferry drinks between rooms.

References

• iRobot: Roomba 600
• Artifical Intelligence Center: Mapping with the iRobot Roomba