![Image](http://www.skooldays.com/blog/wp-content/uploads/60s-arcade.jpg)
But think of what the controllers could have been like, if something like the Magnavox's rifle was anything to go by.
Here's what I think. A tape player would run backing and guitar tracks, with the controller's switch completing the overdub playback circuit. There could have been two playheads set apart by a beat, with light bars fired by each for cues. That may have handled the moving notes on a stave.
(And yeah, you could also have had a compact computer display triggered by some gates, by the time Get Back was done. But I'm sure the guys would have gone with the lights.)
Inaudible tones on the guitar track could've triggered a counter mechanism, different pitches matching up when you got the buttons right. That would take care of the score. And if too many tones were missed by a certain point, the tape would stop, taking your coin with it. If not, a sizeable spool of tape and picture slides may have handled the levels. A simple computer circuit (or clock and switch) could have handled that, giving you the essentials of what we've got now!
![Image](http://www.libertygames.co.uk/images/1/products/3095_guitar-hero-recon.jpg)
Would have been expensive and rare but by, say, 1969, who's to say it wouldn't have recouped its investment thousandfold?
Different story 15 years on though. Anyone could have the Beatles on playalong computer by then.
So what about that then? How could you have done it back in the day?