On Mon, 25 Jun 2007 20:04:32 +0100, "Cableguy" wrote:

Default, Thank You very much for you input, with it I learned the "Zero
Seeking" term...

What I want to acomplish is a movable faceplate for a car audio system that
would Act when the power was feed to the circuit and then return when
powered off.

Like this.

car key in On position go from A to B and Stop
car key in OFF position go from B to A and stop

I havent yet startred the face plate movement design because I havent yet
decided how far the movement should go, althought taht is not important to
the circuit design...

Once again Thank you for your input...


Paulo Gomes

Some car radios had a system like that back in the 70's - 80's. Turn
on the radio and the telescopic antenna would extend, turn it off and
it would retract into the fender. Used a reversing motor driving a
push pull cable. Limit switches were the only logic.

I used a similar idea to make a bank of 12 air valves for a wood pipe
organ. The idea was to simultaneously open or close 12 valves but I
didn't want to build 12 separate air valves. I used wood slide
running in a channel that had holes spaced in it to open or close the
12 air paths from the keyed air to the pipes to change the "voice." A
felt lining made it reasonably air tight - but it was hard to move.

A 120 VAC gear motor turned a disk with an offset pin/bearing to
change the rotary motion to reciprocating motion - like a crank shaft.

Limit switches on each end of the slide stopped the valve in the open
or closed position. One synergistic effect was that the slide had
high torque and slow speed at the stop positions, so it easily
overcame the start up friction when moving from a stop.

--

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----