The 486 that [someyob] is restoring had the Turbo button, but sadly there was just a simple LED to show whether or not it was engaged.

As if you already weren’t agonizing over whether or not you should build your own arcade cabinet, add this one to the list of compelling reasons why you should dedicate an unreasonable amount… ...

Makers, looking for a project to keep them busy this weekend may be interested in a new DIY Arduino arcade game project which uses LEGO bricks and Arduino ...

There is an example of a programme that differentiates between long and short push-button pushes on the Arduino.cc website, but I was not taken it.