Rohit is an engineer who found himself turning through pages and pages of PDFs. The solution he created, from his site:

Now the simple solution would be to buy myself a jog wheel / spinner. Give the jog wheel a slight twist and its momentum would keep it gliding over pages and pages of the boring PDF. But I’m an engineer. So I decided to build myself one (obviously the phrase “Why buy a cow when milk is so cheap” does not apply to engineers).

Rohit reverse-engineered the pinout for the chip on a USB mouse to find the right pins to attach the VCR head to. Once finished, his device works like a charm, and looks pretty sharp too.

[via Dangerous Prototypes]