🚀 go-pugleaf

	The standard used by almost all the current generation of servos is
a TTL level signal that is zero normally with a positive going pulse that 
varies in width from 1.0 to 2.0 msec.  The pulse rep rate is 60 Hz and servo
neutral is 1.5 msec.  You can see this signal easily if you hook a scope up
to a servo output port on a receiver.  The servo leads are normally +5V (red),
gnd (black) and signal (white or some other color).  There were some brands of
radios that used the inverse of this, i.e., normally +5V with a negative going
pulse.  Don't know of any modern radios that still use this though.

	Its easy to synthesis the signal.  Easiest solution is a pair of one-
shots (74121) where the first runs preset at 60 pps and triggers the second
whose pulse width is contolled by a pot.  555s will also work but usually take
more circuitry.
--

					THANX, John Moonan
					SYSOP, 495th R/C Squadron
					Groton, MA