I love cycling and I love the iPad, but you'll never see me using both in unison. Ever. Not so for the cycling enthusiasts at Maya. They've created the "Sprocket Pocket" -- a industrial nylon patch with integrated zipper and protective screen overlay for the iPad that can be ironed or sewn on to any garment in minutes.
The idea is that you put your $500 to $830 iPad into this patch pocket that you iron onto your clothes, and then ride around with it on your back going at speeds of up to twenty miles per hour. The pocket is to be used in conjunction with the MAYA Sprocket app, which uses the iPad's accelerometer to automatically display images on screen for drivers to see. If you stop or begin to slow down, a big stop sign is displayed. If you turn left or right, a left or right arrow appears.
The device is good in theory, but seems excessive when simple universal cycling hand signals will work just as well. And I don't really want the jerk who's already tailing me to speed up to see what that big glowing panel is on my back. Speaking of which, you get hot enough as it is cycling in the summer. Do you really want a 10-inch aluminum device with a massive heat-generating battery strapped to your spine? In this case, impracticality outweighs any actual function.