Does anyone sell one of these premade? I've seen quite a few circuits out there to make your own taking various approaches, but is there something prebuilt that I could just order online or something?

Low-current, momentary action pushbutton switches, such as PCB-mount ‘tactile’ types, are cheap, and available in an abundance of different styles. Latching types, on the other hand, are often larger, ...

A power adapter for a car car allows you to run everyday devices like handheld computers, televisions, video cameras, and even other power-hungry electrical appliances like refrigerators, hair dryers, ...