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Momentary switch question


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#1 Kaleb

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Posted 10 May 2013 - 03:55 PM

What I have is a momentary switch, null-2.jpg

Would it be plausible to cut two prongs off? So I can make a better box to hold it? Second thing is that I need to extend this about 1mm or so, is this made up of PVC? Or what material and would it be ok to glue a piece of styrene to it?

#2 Ace-Garageguy

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Posted 10 May 2013 - 04:08 PM

One reason the legs are as long as they are is to allow solder connections to be made without melting the guts of the switch, so keep that in mind.

 

The housing may be PVC, styrene or several other hard plastics. You should be good to go with a CA (superglue) adhesive...probably.



#3 Kaleb

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Posted 10 May 2013 - 04:17 PM

I'm keeping the length of the legs, just the other two that may/may not be used. I'm not 100% how these type work.

For the button, ill pick some up tomorrow. I need to get to the dollar store anyway for some remote switches.

#4 vypurr59

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Posted 10 May 2013 - 04:57 PM

You can cut or trim back 2 leads. You will have to test to see which ones are the 2 you need. If you have an ohmmeter, you can connect between each leg and depress the button to see the ones you would need to use. If you do not have an ohmmeter, you could also use a battery and a light bulb. I have not tried to glue to styrene, and the ones I have the button is a rubber material.


Edited by vypurr59, 10 May 2013 - 05:06 PM.


#5 Kaleb

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Posted 10 May 2013 - 05:12 PM

I got thinking about how this thing works,

Being just a momentary switch I press it, the lights come on. I let off they go off. Simple logic

But having four prongs
Would press once, it comes on and stays on?

Press again it goes off

I do this by using all four leads?

This is a plastic, it came from a "mother board" I am in hvac and I tear the old thermostats apart for switches like these.

#6 vypurr59

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Posted 11 May 2013 - 02:31 AM

That is not correct. Think of this as 2 momentary switches in 1 case. 2 legs are 1 switch and the other 2 legs are the other.



#7 Guest_G Holding_*

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Posted 11 May 2013 - 03:56 AM

An ohmmeter will show you what the legs do....I suspect they are dual legs.....The package will tell you what is what



#8 Kaleb

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Posted 11 May 2013 - 04:10 AM

Jeff, ok more of wishful thinking on my part. Hoping for a flashlight effect.

Greg, no package for these. I will be getting the meter out today, that is the easiest way.

#9 Ace-Garageguy

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Posted 11 May 2013 - 04:43 AM

Having four legs, this is most likely the correct internal diagram for your switch. As stated above, it's PROBABLY essentially two switches side by side, in parallel.

 

atswitch.png

 

IF you're certain it's a MOMENTARY CONTACT switch, that means it's only ON when the button is held down.

 

Checking the current paths through it with an ohm meter is the only safe way to be certain, unless it has a diagram engraved on the housing. Many switches do. Make notes of your meter test results as you go.



#10 Kaleb

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Posted 11 May 2013 - 10:46 AM

Right, I bought a cheap flashlight to tear apart to see how it works. I have a couple different designs on the momentary switches. One has four like shown, the other has two legs. Both of which are referred to as a tactical switch. The switch I have came from a thermostat, raising the temp, another to lower. I will post updates on how this particular one works. Which I'm sure it works as mentioned.

#11 Kaleb

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Posted 11 May 2013 - 11:33 AM

Ok the results are, are like bill posted.

Checked the top two together and the bottom two together, the both show closed(continuency, ohm out, etc)

So I could snip two off if need be, so I can make a box to fit it.

#12 Mike_G

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Posted 11 May 2013 - 02:13 PM

That type of switch contact is commonly used in full-logic (solenoid-operated) cassette decks and VCRs and the like- the main reason it has 4 legs is to provide a secure mounting to the PC board. If you're talking about extending the pushbutton, they do make those with a longer shaft, but you can certainly glue a piece of styrene on to accomplish the same thing. I'd use 5-minute epoxy for that.



#13 Kaleb

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Posted 11 May 2013 - 03:11 PM

I had one, that had a longer shaft. I would prefer it over the current. I would still have to glue a piece to it even though it was longer.

#14 blunc

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Posted 11 May 2013 - 08:55 PM

I would advise against trying to glue an extension to the button on the switch since any excess glue will foul the switch and make it useless.

 

A free floating extension that contacts/presses the momentary switch is better (IMHO), this is similar to how most computer CD/DVD open/close buttons are configured. (you can rob these switches from old electronics, some even have miniature on/off pcb mount switches).

 

regarding the legs/solder lugs, some are 2 separate on/off circuits and some have 2 legs per contact side for extra current capacity but most of the time it's just for more secure mounting to the circuit board.



#15 Kaleb

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Posted 12 May 2013 - 03:34 AM

Mike, I wish I could follow that, but in this situation I cannot. I do realize that any glue that gets beside the button will make it stick. The process that it requires has to be precise so I can not have any excess glue in any spot. I would show everyone, lol but everyti me I show an " in progress" I never progress from there. So when I'm done, I will show everyone and the steps I went through.

#16 vypurr59

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Posted 12 May 2013 - 04:44 AM

Mike, I wish I could follow that, but in this situation I cannot. I do realize that any glue that gets beside the button will make it stick. The process that it requires has to be precise so I can not have any excess glue in any spot. I would show everyone, lol but everyti me I show an " in progress" I never progress from there. So when I'm done, I will show everyone and the steps I went through.

I know the feeling about the WIP, I usually forget to take pictures, and when I remember, it is already done...lol