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From: irwin@m.cs.uiuc.edu
Newsgroups: sci.electronics
Subject: Re: Lasers
Message-ID: <21000101@m.cs.uiuc.edu>
Date: 12 Sep 90 19:07:00 GMT
References: <26@<1064>
Lines: 47
Nf-ID: #R:<1064:26:m.cs.uiuc.edu:21000101:000:2519
Nf-From: m.cs.uiuc.edu!irwin    Sep 12 14:07:00 1990


/* Written  4:38 pm  Sep 11, 1990 by DAVE@ORION.BITNET in m.cs.uiuc.edu:sci.electronics */
>Our elevators on campus are always quite busy, and we are looking to modify
>them with a 'remote control' to allow authorized personnel immediate access
>to a car when nessecary.  We hope to do this by placing radio-controlled
>switches in parallel with the inspection key switches, and certain floor
>buttons.  Can someone please give us some advice and schematics for INEXPENSIVE
>circuits that can control at least 5 switches independantly.  I would like one
>or two of them to be 'permanent toggle' controlled, ie: a button is pressed
>on the transmitter, causing the switch to be closed, untill the button is
>pressed again, upon which point the switch will be opened.  I need other
>switches to be momentary, closing the circuit only while the transmiting
>button is pressed.  My knowlege of electronics is not great (obviously) and
>I would like the RC circuit to finally control a relay - which I can connect
>across the switch terminals.  If my objectives are not clear, please email me
>and I can explain them further.  If NOTHING ELSE, I would like the schematic
>for a single xmitter/reciever to control ONE relay - momentary contact.

> thanx, dave michaels   dave@mercury.njit.edu
/* End of text from m.cs.uiuc.edu:sci.electronics */

Might I suggest for a single contact control, that you consider the
home garage door opener as a possibility.

The garage door opener that I have in my home was bought in the 1960s,
and though the opener mechanizm worked fine, the radio link left
something to be desired. Aircraft overhead, police cars and other
things could cause it to open. Also, it was an obsolete design using
tubes, which would get weak and need replacement.

I purchased a radio system from Sears, which is solid state, and has
a program switch in the receiver/transmitter, that sets the code that
the unit will recognize. Now, I never find my door open unless I want
it to be open.

The thing is, you can purchase the receiver, and as many transmitters
as you like, program the code of all to be the same, and they will
be unique to your needs. The receiver would be installed at the elevator
control head, not in the car, to activate the necessary circuit in the
control assembly. An antenna could be attached to the receiver that would
pick up the transmitters when they were activated.

This would only provide you with a single contact, but would be simple
to implement.

Al Irwin
irwin@cs.uiuc.edu