The Rasberry Pi is receiving more public attention than almost any other computer release I can think of. A lot of the excitement is about the ultra low cost (only $35 for the more expensive B board) and all the great stuff you get for the money.
Other than a mention or two by the Raspberry Pi creators I haven’t yet seen a discussion of its potential benefits for DIY robotics – and that’s puzzling as it would seem a great option.
The Raspberry Pi falls in the Single Board Computer (SBC) bucket and is not a traditional microcontroller board. This means you don’t get onboard analog to digital converters (ADCs) or a whole lot of general purpose IO pins (GPIOs). You do get 8 GPIO pins plus a few dedicated communication interface pins which should be plenty with an optional expansion board. You also get a 700MHz ARM processor and all the standard computer connectivity options like Ethernet (on the B board), 2 x USB 2.0, HDMI for HD video & audio, composite video, audio jack, and SD Card for the Linux OS and application code which is all really great for putting a DIY robot together – much more than the typical microcontroller board.
The GPU/graphics capability of the System On Chip (SoC) ARM processor is well beyond that required for most robots, but maybe there’s an avenue here for some cool augmented reality effects on a live video feed from the robot!
Power draw of the board is mentioned as a very respectable 2 watts or less – again a great spec for mobile DIY robots.
What major additions does it need to support a robot?
- It needs to be fed power through a micro-usb cable, and apparently an easy way to do this is to hack an inexpensive cell phone charger cable.
- It needs a Wi-Fi USB adaptor, of which dozens are available for anywhere from approximately $14 and up. The supported Tenda USB 11n adapter is approx. $20 on amazon.com.
- It needs a USB Camera of which their are hundreds of options, but auto focus is a desired feature. The Hercules DualPix Infinite Webcam seems a good low cost contender at $35, and the Microsoft LifeCam Webcams at $35 to $50 are a reasonable choice & are reported to support Linux through the Linux UVC driver.
- It needs a motor control board, and several groups are working on producing them for the Raspberry Pi, including the GertBoard shown here. No price or availability info is up for the GertBoard just yet,but a solution will be available soon.
With your chassis of choice and these few additional parts you should have a powerful, almost plug together basic robot for something on the order of $150 – $200 plus tax/S&H, and of course plus a fully outfitted chassis with motors, gearboxes, wheels/tracks, and battery. Examples of good ones are the Surveyor SRV1 chassis from osbots ($185), or the Dagu Wild Thumper 4WD All-Terrain chassis ($215) but there are many cheaper options. The total for a robot built this way should be on the order of $350-400 plus tax,S&H. Not bad for a really solid robot hardware platform.
Raspberry Pi model B