TurtleCore Tacks Cortex-A8 On To iRobot Create

June 25, 2012
Gumstix's TurtleCore ties any Gumstix Overo module to the iRobot Create. This is iRobot's development platform that is based on its Roomba robot cleaner.

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).

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.

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.

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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