alt.embedded

TurtleCore Tacks Cortex-A8 On To iRobot Create

Gumstix sells a wide range of very compact modules including its Overo line. It is based on the OMAP system-on-chip from Texas Instrument's the is based on Arm's Cortex-A8 processor. Gumstix new TurtleCore is a board that ties any Gumstix Overo module to the iRobot Create (Fig. 1). The iRobot Create is iRobot's development platform that is based on its popular Roomba robot cleaner. I originally tried the Create using the iRobot Create Command Module (see Commanding The iRobot Create).

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Figure 1. The iRobot Create Command Module plugs into the iRobot Create platform.

The iRobot Create Command Module actually provides an interface for the Create to other microcontrollers. I took advantage of this in the past but getting power for the micro required adding an external power source. It was also a bit cumbersome and any test system took up room in the cargo bay.

The TurtleCore board (Fig. 2) replaces the Command Module and has a socket for the Overo modules. The TurtleCore is relatively simply with a USB-to-serial interface and three USB sockets. The socket on the bottom of the TurtileCore provides access to power and communication with the Create.

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Figure 2. The TurtleCore plugs into the iRobot Create.

The Overo module plugs into a pair sockets on top of the TurtleCore. The TurtleCore links the module to the Create and the USB sockets on the TurtleCore (Fig. 3). There are a number of headers on one side of the TurtleCore that expose additional I/O from the module.

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Figure 3. An Overo module, like the Air COM, plugs into the TurtleCore that provide USB connections and a serial link to the iRobot Create.

The TurtleCore was easy to install and the most challenging thing is finding a way to mount the two external antennas that come with the Air COM. These are used for the 802.11 b/g WiFi interface. I used the USB serial console interface for the initial Linux set up. This was simply a matter of setting the SSID and passsphrase for the WiFi link. SSH WiFi access then provides the necessary remote console support.

Overall, the TurtleCore and Air COM are a great combination. The Air COM also has a MicroSD socket for expansion. It also has Bluetooth support but I have not tried that yet.

A version of the Robot Operating System (ROS) is in the works. ROS has typically been implemented on a PC (see Frameworks Make Robotics Development Easy—Or Easier, At Least). ROS and the Create have been used in a number of projects including the Billibot (see Cooperation Leads To Smarter Robots) that uses Microsoft's Kinect (see How Microsoft’s PrimeSense-based Kinect Really Works). The combo tends to be top heavy and uses a laptop or netbook.

In theory, it is possible to connect the Kinect via a USB port but drivers could be an issue. The Air COM has a camera interface and connect to devices like Gumstix's Caspa VL camera.

I'll let you know how the software works out when I have had more of a chance to check out the combination. I did have a couple minor caveats so far. First, there is no power or reset switch on the TurtleCore. I had to pull the battery to force a hard reset but I only had to do that a couple times when I locked up the system while experimenting with it. Second, mounting the Air COM antennas is going to be a chore at least if the connection to the Create's frame is done in a professional fashion. Otherwise, the TurtleCore is just what the doctor ordered. It is inexpensive, a snap to install and provides a solid platform where you can select the module you need for your project.

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