Modular Cooperating Robot Components.

The Linkbot platform from Barobo, Inc., applies a sort of swarm robotics to individual modules that can be easily connected, expanded, programmed, and controlled. The idea is to encourage young children to become interested in robotics early on to help fill the gap where interest in robots in education is declining. Read on to find out what Linkbots are made of, as well as how they work and what they can do.

Linkbot Parts, Technologies, and Proprietary Capabilities.

Linkbot is a modular robotics platform that consists of like components you can connect or link together to form higher order robots. The components come with a number of built-in capabilities, including a 802.15.4-compliant ZigBee-capable wireless radio transceiver operating in the 2.4 GHz band. Roboticists can use this to communicate wirelessly, create mesh networks, and control and monitor Linkbots remotely. Linkbots also include a rechargeable lithium-ion battery good for three hours of run time; a three-axis accelerometer for detecting free falls, bumps, and tilt angles; absolute encoding; compatibility with Arduinos; and ease of hacking.

As mentioned, the Linkbot’s internal chip is Arduino-compatible (the Leonardo). The ATmega128RFA1 by Atmel runs at 16 MHz. This integrates with an eight-bit AVR microcontroller. Builders can re-Flash with their own firmware using the onboard boot loader.

There are also Arduino-compatible breakout boards and accessory boards that are available, so users can add sensors or add the Linkbot into their existing projects. Expansion boards plug into the robot, enabling the roboticist to connect several devices such as IR proximity sensors, buttons, and switches, photo detectors, and more LEDs.

You can use a phone cable to connect the Bluetooth-enabled breakout boards or electronics to Linkbot power.

It uses a standard phone jack (you would find at any hardware store) which has four lines: two power and two I2C communication. Barobo set it up so a Linkbot outputs 5V on the breakout board, so you can power your attachments off the built-in lithium-ion battery. Bluetooth 2. 0 enables the Linkbots with direct wireless communication with computers and mobile devices such as Android phones and tablets.

Linkbot uses Arduino Xbee and accelerometers, as well. There’s also a buzzer capable of playing multiple notes and tunes to give audio responses to various inputs. Linkbot’s BaroboLink Software uses a graphical user interface (GUI) to run programs, actuate motors, and read sensors. The robot’s polycarbonate housing is very durable and has been drop-tested from second story buildings (Barobo does not recommend this to users).

The robot comes with a proprietary TiltDrive technology that enables the user to drive a Linkbot via either a smartphone equipped with an accelerometer or another

Linkbot, which also functions as a remote control.

Once a Linkbot is BumpConnected to one or more other modules, the built-in TiltDrive mode allows the user to tilt a module forward, back, left, and right to drive the robot around.

Linkbot’s CopyCat technology enables builders to use the same smartphone (or another Linkbot) to control the motors in another Linkbot (motors have a high torque to weight ratio, are light but strong, and produce up to 100 oz torque). CopyCat takes the rotations you make on one Linkbot and drives the other modules to copy it.

This is cool when you want to quickly make a robot move. For example, you can build two identical grippers made out of Linkbots, then BumpConnect them in a certain way so any motions you make one gripper do, the other will do remotely.

Linkbot’s PoseTeaching technology enables the user to program motions into any number of Linkbots to create a motion by manipulating and posing the Linkbot with their hands. PoseTeaching is a new way of programming robots where you record individual poses with the Record button, then play the poses back again by pushing the Play button on the outside of the module. There is also an Erase button, and the routine will loop automatically. You can do very basic repetitive motions, or create complex control paths.

Linkbot’s BumpConnect technology enables the user to connect multiple modules by simply pushing the Pair button and bumping the components together. BumpConnect uses the accelerometer and Zigbee-compatible chip to allow any Linkbot to wirelessly connect to any other Linkbot. Once you pair Linkbots, the Zigbee-compatible chip has a line-of-sight range of 100 meters. «We’ve driven robots down the block and around the corner,» says Graham Ryland, president of Barobo.

More of the Linkbot’s Functionality.

Linkbot uses absolute encoders which are continuously rotating, and brushed gear motors to drive the hubs (patent pending).

Linkbot has a multicolor LED with red, blue, and green (RBG) to help tell them apart. Feedback from users stated it was actually hard to tell them apart when they were moving around together. When you BumpConnect, the Linkbots choose a color at random for the group color. There are also Mode colors for TiltDrive (green), CopyCat (turquoise), and PoseTeach (blue).

Linkbot comes with lots of accessories, including SnapConnector mounting surfaces for various SnapConnector parts (wheels, plates, grabbers) that click on to the outside of the Linkbot to form walking robots, and also climbing and rolling robots. You can connect your own accessories using standard screws.

Linkbot accessories are available to download from the company website, so builders can 3D print them to use with the Linkbot, hopefully design their own, and share them with others. You do not have to have a 3D printer though. Most of the examples in their Kickstarter video and updates are made out of cardboard.

Linkbot also takes advantage of force feedback capabilities. In CopyCat mode, you can feel force feedback when you stop the rotation of the robot you are controlling. It compares the angle of the controller module to the output angle of the controlled module; if they deviate too much, then the motors in the controller robot lock up. It is very early in its development, but it is really engaging and fun to use.

ProtoMold makes Linkbots using plastic injection molded parts. A company called Pride handled the controller board. Pololu supplied the motors.

Conclusion

Barobo’s first year of success with Linkbots shows there is a huge interest in these types of robots. Anything that can help spark imagination in children of all age’s minds is a good thing.

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