RE: 555 timer circuit

Hi Tyler, Bill, Rich, and the list!

Got the circuit posted under CIRCUITS. This 1974 circuit got it's power
from a stepper driven radiation sampling system. I run mine off a 9v
battery. R1 and CR1 regulate to 5.2v, omit it and use +5v if you want.
C1 and it's charging circuit give the roughly exponential acceleration /
declaration curves. CR2 discharges it for next startup (I think). The
rest is a blur in my mind.

The step pulses start off slow, then accelerates to speed. In use,
several push buttons (not completely shown) both apply power, and route
pulses to the appropriate STEP line of the driver wanted. A direction
switch should also be provided for each axes to be controlled. Two
buttons can be pressed at the same time. I drove my first robot with it
this way. A little like driving a tracked tank or D6 Caterpillar
tractor!

When this circuit was drawn, it wasn't step/dir, it was CW/CCW, as can
be seen in the +X, -X, etc. I also have discrete stepper driver
circuits, of the same era!

If I can figure out where I put it, I'll determine the starting and
running frequencies.

Alan KM6VV