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simple question (probably..)

Q

quintero

Jan 1, 1970
0
i have this door opener which has a 2 wires connected to it, basically
if i connect the 2 wires together the door opens.
now i want to connect these wires in some way to the com port in my
computer, so i can control the door with some software. i know how to
set RTS and DTR, but how do i complete the ciruit and connect the 2
wires together?
 
J

John Fields

Jan 1, 1970
0
i have this door opener which has a 2 wires connected to it, basically
if i connect the 2 wires together the door opens.
now i want to connect these wires in some way to the com port in my
computer, so i can control the door with some software. i know how to
set RTS and DTR, but how do i complete the ciruit and connect the 2
wires together?

Like this:

+V
| +------->TO DOOR WIRE 1
+------+ |NO
|K | O-> |
[DIODE] [COIL]- - - -|COM
| | O--->TO DOOR WIRE 2
+------+
|
C
RTS>---[4K7]-+---B NPN
|K E
[DIODE] |
| |
SIGNAL GND>--+-----+
|
GND>---------------+

Assert RTS momentarily when you want the door to open.
 
B

Bill Bowden

Jan 1, 1970
0
i have this door opener which has a 2 wires connected to it, basically
if i connect the 2 wires together the door opens.
now i want to connect these wires in some way to the com port in my
computer, so i can control the door with some software. i know how to
set RTS and DTR, but how do i complete the ciruit and connect the 2
wires together?

You can probably use a solid state relay. The relay will
have a LED inside that controls a photo sensitive switch.
They will usually work at 10-20 mA, but I'm not sure how
much current you can get from the com port. Look around
for a SS relay that operates on low current of just a few mA.

-Bill
 
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