2 way Microswitch?

[bigoldblack]

Hi,

I'm looking for a 2 way microswitch or something similar if there is such thing.

I have something moving one way that i want to trigger the switch and then I would like to trigger it again while it is moving back through the switch. Here is a quick diagram. I'm using a PLC to control all of this.

Is there any physical switch I can use besides a photoeye sensor?

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[jbeng]

Seems to me you could use a microswitch like the one you pictured, only one with a roller on the arm. Put a cam-style switch actuator on the "moving thing" and you're there.

 

[ke5frf]

Poster jbeng was thinking along the same track as myself...but your question leaves out a lot of details that might be relevant.

What will actually be moving back and forth? I mean what sort of object will be actuating this switch? Will it be constant contact, intermittent contact, or a combination of both?

Will your switch be some way causing a response in your object, or is it simply going to a counter circuit, visual indicator, or triggering something else of another nature?

If you are simply looking for an intermittent, momentary contact closure per each pass of the object by the switch, a roller type switch would certainly work, or a rocker style would work if you want an on/off/on/off switch closure.

You could also purchase a snap action switch with multiple poles if you have more than one circuit to trigger...the method of actuating one of these switches can be fabricated by the user: **broken link removed**

And of course one of the easiest ways to do it, if a flag can be passed through, is the forked light barrier (optical) switch. Is there a particular reason this is out?

Or a hall effect sensor might be used if a magnet can be fixed to your object.

Or if you are still inclined to mechanical switching, a reed switch or simple magnetic switch can do as you want without even making contact with your object.

 

[ke5frf]

One more thought, if you are triggering a logic device with your switch, especially one which changes the state of the output with every trigger or a counter, it is advisable to debounce the switch with a capacitor.

Oh, and if you go the simple microswitch with roller route, or similar, remember that commonly these switches are momentary contact. However, if you want on/off changing state, you can either get a toggling roller switch OR you could use a flip-flop.

 

[bigoldblack]

I haven't thought of a roller on the microswitch. I might get one and give it a try.

Here is a couple pictures I plan to use it for.

The wood is the piece attached to wheel that is going to move.
The purpose of the microswitch is to stop whenever it hits a rubber tab.
As you can see, the microswitch would only work if the wood is only one way and not the other. Would the roller be able to solve this problem?

Thanks.

**broken link removed**

**broken link removed**

 

[madhippiescientist]

The roller would work, but i suggest "rounding off"
the rubber tabs (round off rubber?). Maybe a drop of
JB weld on each tab, and position that switch VERY
carefully. Another suggestion. Micro magnets with a
reed switch (no mechanical contact whatsoever).

 

[bigoldblack]

I never heard of a reed switch before but I looked it up and it seems like a good idea. Are they very common. I might give both a try and see which one works out better. The position does need to be pretty accurate as I'm making a fork lift system with 3 axis.