mikroElectronic offers a free online book about PIC Microcontrollers. The book is very well illustrated and cleary written with good examples. While it mostly focuses on using the PIC 16F887 microcontroller with assembly, large portions of the book are also applicable to other PIC microcontrollers. They also sell a print copy with CD for $24.
The Pololu 3pi Robot is a line following and maze solving specialist. The 3pi uses an Atmel AVR ATmega168 processor and is Arduino compatible and has expansion boards available for adding additional features. The most interesting thing about this robot is the speed at which this robot is able to follow lines without any odometery information. The package with everything you need is available for $119.95.
Linkages, 4-bar mechanism, and other multi-bar mechanisms are useful for many robotic applications such as robotic grippers, payload bays, arms, legs and a variety of other robotic limbs.
The WATT Mechanism Suite from Heron Technologies provides a software solution for designing mechanisms from arbitrary motion paths.
The user interface was easy to use and I was able to produce a simple four-bar mechanism design in under an hour. WATT outputs a variety of information such as the path error and velocity in excel format and can export geometry information in DXF. While, it was not initially obvious to me when the software encountered a problem due to the mechanism jamming, the software generally produces good results for a wide variety of cases.
The list price for a single-user copy is 1575.00 Euros, however there is a 50% educational discount available for qualified organizations.
If you are on a budget you may want to consider The Geometer's Sketchpad which is available for $39.95. The Geometer's Sketchpad is a software program designed for use with "smart" whiteboards. The animation mode can be cleverly used to cheaply produce motion simulations for multi-bar mechanisms without having to resort to pieces of cardboard and Brass Fasteners. The linkage library provides some good examples of what the software can do if you are persistent enough to figure out the interface. It is helpful when learning how to use the software to remember that "smart" whiteboards are lucky to have one mouse button, and that a line can be defined by two points. Once you manage to figure out the horrible user interface, The Geometer's Sketchpad turns out to be a pretty good program for the price.
What people really need is a Hello Kitty sticker on their Roomba...
iRobot has also recently announced a $3.5 million dollar order from the Army for 26 PackBot robots
I saw a video once that almost brought me to tears, where a little robot rolled up to an IED and tried to disarm and it ended up kicking the bit bucket. I thought to myself, "that robot saved a human life". In the future I hope our robot overlords will think kindly of me...
If the iRobot Dirt Dog is not powerful enough to clean up your mess, you may want to check this out.
Somewhat surprisingly, Lely had sales of 273 million euros while iRobot had sales of about 249 million dollars. I was not expecting the market for farming robots to be doing this well, but I guess the labor costs are much lower and the cows seem to be happier with automatic servicing.