Classic Computer Magazine Archive COMPUTE! ISSUE 52 / SEPTEMBER 1984 / PAGE 131

Atari Paddle Fixer

William Griner

Here's a quick fix for the Atari paddle jitters that still preserves the paddles' range.

The Atari paddles are so sensitive that the heat of a hand or any jarring can change their value. Some paddle-based games don't take the sensitivity into account, causing their characters to flicker annoyingly. Try this:

KN 1000 REM get the paddle value
IG 1010 PV = PADDLE (PN) : IF ABS
   (PV - OPV) > 1 THEN OPV = PV : RETURN
LF 1020 PV = OPV : RETURN

where:

PN is the paddle number (0-7)
PV is the value read from the paddle
OPV is the old paddle value (initialized to whatever value you wish)

Centered Values

The above subroutine keeps the paddle centered between the adjacent values. It takes a difference of two steps or more to change the paddle value. This is not to say that the paddle will use only all even or all odd values. For example, if the paddle is at value 77, it will not be allowed to move directly to 76 or 78. If you want to move from 77 to 78, you will have to move to 80 or 75, then to 78.

Better Than Brackets

This method is better than dividing the paddle range by a number since doing so creates fixed brackets of possible values and does nothing to keep the paddle value from straddling the bracket boundaries. This method could also be used to keep the paddle in a wide bracket, allowing only for coarse movement, yet giving access to the entire range of the paddle's values.