I am doing research on Dance Mat Game Controllers. I found U.S. Patent 4,720,789. I am looking at Fig. 3 and col. 2 ln. 60-col. 3 ln. 10. From my understand the pressure sensors/switches number 78 are analog. However when the signals from the pressure switches go through the shift register number 82 the signals are bits (as stated in aforementioned text) and therefore digital. As such, my question is: May I consider the shift register number 82 as an analog-to-digital converter (ADC), or am i reading too much into what is disclosed? Opinions?

Google Patent:
http://www.google.com/patents?id=-40zAAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false

 

Probably the input pressure sensors are a variation of normal switches, so just switching the inputs between 12v and gnd creates the "A/D" conversion.

 

Hah, they have patented a short circuit on page 2.