If you haven't had enough time to play with your cat lately, an automated cat toy is a great way to get them moving and keep them entertained. This DIY version is easy to assemble and code.
Using a WIZwiki board, an ultrasonic distance detector, and a basic servomotor, Instructables user irinak1 was able to piece together a toy any cat is sure to find intriguing. Some basic soldering and coding (provided in the guide) is required, but once it's complete, the servomotor will swing the toy arm with the kind of quick jerking motions cats like. Turn it on when you have to leave and your cats will care even less that you're gone. You can check out the complete guide at the link below, and see it in action in the video above.
Of the cats, by the cats, for the cats [Instructables]