Relay computers

From: Paul Koning <>
Date: Fri Sep 24 15:27:56 2004

>>>>> "Vintage" == Vintage Computer Festival <> writes:

 Vintage> On Fri, 24 Sep 2004, Paul Koning wrote:
>> sending of ball hitting paddle or wall is done with contacts in
>> the mechanism, not with the logic itself. So the relay control
>> has to

 Vintage> Perhaps I read it wrong but the PONGMECHANIK uses logic to
 Vintage> determine when the ball has hit a paddle or wall.

 Vintage> "Element 2: The movements of ball and racquet, as well as
 Vintage> the collision detection take place in a metal chassis under
 Vintage> the glass cover. Each moving game compoent has a mechanical
 Vintage> counterpart, which is moved by electric motors. When these
 Vintage> parts collide, contacts are closed and the relays in the
 Vintage> computer switch the direction of rotation of the motors."

What I meant is that the relay control is not doing position
calculation. It doesn't know where the ball and paddles are (only
whether certain motors are turning). Detecting ball hitting paddle
is by a contact on the ball carriage hitting a contact on the paddle

In a sense the system is a hybrid computer: a digital control system
driving an analog computer. The analog computer is the set of motors
and switches on the playing field display. Or to put it differently:
the digital computer sets the motor speeds, and the analog computer
integrates that over time (double integral, dx and dy) to find the
position of the ball.

Received on Fri Sep 24 2004 - 15:27:56 BST

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