Re: Home switch testing?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Harvey White <madyn@i...>
wrote:

> On Mon, 05 Jan 2004 05:45:47 -0000, you wrote:
>
> >Hi, I just received some slotted opto sensors
> >that I was planning on using for home sensors
> >on my retrofit.
> >This is where I got them from.
> >
> >http://www.allelectronics.com/cgi-bin/category.cgi?
> >category=435&item=OSU-50&type=store
> >
> >They have 4 leads on the bottom two are for 6 volt
> >power + and - and the other 2 are suppost to be
> >a normaly closed switch wich is disrupted when a
> >deflective object is penetrating the slot.
>
> Well, probably not a switch.
>
> >With my obvious limited knowledge about electronics
> >I tryed to hook the sensor up to test its function
> >using a couple of D cell batterys a 6 volt powersupply
> >a small voltage lightbulb and a multytester for electronics.
> >I have not been able to get this sensor to do any kind
> >of verifyable disruption yet.
> >I tested on 2 of the leads was continuety so I figured
> >this must be the switch side.
>
> well, that's the LED, probably.
>
> >Testing to disrupt the lightbulb did not work in any of the
> >various ways I tryed to set this up.
> >Could any of the more electricly gifted persons please point
> >out what I am doing wrong here.
> >I suspect this may not work the way I think it would.
> >The 2 sensing leads are suppost to be hooked up on 2 pins
> >of the Parallel port of the PC, have not tryed this yet.
> >How could I set this up for testing.
> >
>
>
> Let's give this a try.
>
> 1) the thing is infrared, so you won't be able to see it when it's

on,

> if you have a camcorder of some sort, or a digital camera, it might

be

> able to see infrared, otherwise, radio shack/tandy has a little

strip

> that will glow under infrared light, you can use that.
>
> the emitter of light is an led. Wire a 470 ohm resistor in series
> with it, and then ground one end, and run the end connected to the
> positive end to the +5 volt supply, this will allow about 8 ma to

flow

> through the diode. When it's conducting, you can expect to see

about

> 1.4 to 1.6 volts or so across the diode.

Is this resistor required just for testing?
You say to hook it up in series, one end ground and the
other to +5 volt would this not be parallel hookup.
Will omiting this resistor prevent it from working?

>
> The second part of this is a photodetector. It's basically a
> phototransistor. One end will be grounded. The other end (plus)

will

> go to the +5 volt supply through a 4.7 K ohm resistor. Take your
> signal to the parallel port from the junction of the resistor and

the

> photodetector.
>
> Electrically, this is the same as an optoisolator, probably of the

LED

> Phototransistor type. Look for specs on the 4N33 or 4N35 chip, then
> that will give you some hookups to study. The difference here is

that

> you can put an object between the LED and the photodetector.
>
> Measure the resistance and see if one port changes resistance with
> infrared... you might be able to use a tv remote to try the sensor.
>
> Harvey

Is the purpose of this sensor to pull the pin +5 voltage down?
I tryed to connect this side with a Lightbulb wired between the
+5 volt pin and the ground pin but I could not get it to turn
on/off while blocking the slot.
Also tryed the multytester insteed of the lightbulb it showed the
5 volt current but it did not alter this voltage durring triggering.
Maybe this is different from just pulling the pin down?
Any simple sugestions for testing this?