cr0sh:
Whippet:
Or you could simply mount a color sensor and somehow program it to make your manipulator arm grab anything that is bright red when it is in the general vicinity of your refrigerator....and how does this supposed robot manipulator arm even -know- where "bright red" things are? A color sensor isn't going to give anywhere -near- enough information to be able to position the arm.
Try putting on a blindfold, and some over mitts, and stand in front of the refrigerator. Have someone else give you yes/no answers when you hand comes near "bright red" in the fridge. Try not to make a mess.
You can't just set up a color sensor and "somehow program" things to get the job done; robotics doesn't work this way. Maybe if there were a designated coke can dispenser always in the same spot in the fridge, and the position of the fridge never changed, and there were some other "guidance" sensors and such to guide the arm/gripper/manipulator into position (and similar stuff on the floor, etc to guide the robot's chassis) - you -might- be able to get away with it (something like early pick-and-place industrial robot systems - where if you can control for every possible variable, you can drop the error rate down low, but you'll never get to zero).
Ultimately, you need a little bit of such a system, coupled with vision and machine-learning software to make an effective system. It really isn't as easy as you think (otherwise, we would have already had the home helper robots we've been promised for the past 50 years already).
As I said - I expect it to take 2 years.