# Wiring Up Momentary Switch for ON/OFF Operation



## Flava0ne (Dec 7, 2017)

I recently purchased a ModMyToys 22mm Illuminated Momentary Switch but I'm having trouble wiring it up for On/Off operation because the included wiring diagram shows only 5 leads, where they're actually 6 leads on the switch. Could someone with some knowledge help me out with this?


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## infrared (Dec 7, 2017)

Yeah that diagram isnt very helpful.
Do you have a multimeter? Ignore the plus/minus pins, they're just powering the LED. If you probe around the other pins as you press and release the button, you'll be able to find a pair that are 'normally open' use those to go to the motherboard


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## Flava0ne (Dec 7, 2017)

infrared said:


> Yeah that diagram isnt very helpful.
> Do you have a multimeter? Ignore the plus/minus pins, they're just powering the LED. If you probe around the other pins as you press and release the button, you'll be able to find a pair that are 'normally open' use those to go to the motherboard


Would the multimeter even give any readings where there's no power to the switch? Or do I have to probe it while the led is connected and on? I don't have a multimeter but been needing to get one anyways.

Also, when leads 1 and 4 are connected, I get the "momentary" on without even pressing the button, then the computer just shuts off.


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## infrared (Dec 7, 2017)

If you set it to continuity mode you should get a beep or a reading on the screen when a connection is made. You want it so there's no reading or beep until you press the switch, and it should stop when you release it.


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## Sasqui (Dec 7, 2017)

Flava0ne said:


> Also, when leads 1 and 4 are connected, I get the "momentary" on without even pressing the button, then the computer just shuts off.



Nice documentation lol.  Infrared has the best suggestion, and no you don't need power to test for continuity... you can use an ohmmeter which is basically the same, open= infinity resistance, closed =~0 ohm resistance.

I'm guessing 1&3 are normally closed until you push the switch and 2&4 are the opposite... or 1&2 and 3&4.  But you really can't tell without testing.  The diagram show pins NC&C and NO&C work on pairs ...NO= normally open NC=normally closed


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## dorsetknob (Dec 7, 2017)

infrared said:


> If you set it to continuity mode you should get a beep or a reading on the screen when a connection is made. You want it so there's no reading or beep until you press the switch, and it should stop when you release it.





Sasqui said:


> Nice documentation lol. Infrared has the best suggestion, and no you don't need power to test for continuity... you can use an ohmmeter which is basically the same, open= infinity resistance, closed =~0 ohm resistance.



Set and use your multi meter to measure resistance no power needed


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## Flava0ne (Dec 7, 2017)

So it's possible to wire it up for On/Off operation without the need to jump any leads like in the provided diagram?


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## Sasqui (Dec 7, 2017)

Flava0ne said:


> So it's possible to wire it up for On/Off operation without the need to jump any leads like in the provided diagram?



Should be, if it's a momentary switch you want you just need to find the pair that is "NO" - Normally Open.  And connect two wires to those.  While the button is pressed, that pair would be closed, completing the circuit.  When button is let go, the circuit is open (broken) again.  That's how 99.9% of power and reset switches work for a PC


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## sneekypeet (Dec 7, 2017)

5 seconds googling the issue comes up with the first hit as a video explaining all of the pin functionality.


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## Flava0ne (Dec 7, 2017)

So, I have to splice/jump the LED+ with the NO lead to get it to function as an On/Off switch?


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## sneekypeet (Dec 7, 2017)

If you want LED and the switch to work as one, it does appear that he connects them both together in the video.


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## Sasqui (Dec 7, 2017)

sneekypeet said:


> If you want LED and the switch to work as one, it does appear that he connects them both together in the video.



Which begs the question, when do you want the LED to come on?  As a function of the momentary switch press, or something else?  If it's only from the power header indicator on the MB, you only need to connected that to the + and - leads on the switch.


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## sneekypeet (Dec 7, 2017)

Sasqui said:


> Which begs the question, when do you want the LED to come on?  As a function of the momentary switch press, or something else?  If it's only from the power header indicator on the MB, you only need to connected that to the + and - leads on the switch.



That seems about right, although I am not sure of the power sent for chassis LEDs is enough to power the switch LEDs.


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## Flava0ne (Dec 7, 2017)

Ideally, I would like the LED to be on while the system is also on, but in the video, it looks like it will only be momentarily on.


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## infrared (Dec 7, 2017)

The LED will be on whenever there's 12v on the + and - pins, so you can either run it off the power led pins on the mobo (led's use very little juice, should be fine to do this), or you could power those pins from a spare molex connector. Either method will mean it stays lit whenever the pc's powered up.


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## Papahyooie (Dec 7, 2017)

Flava0ne said:


> Ideally, I would like the LED to be on while the system is also on, but in the video, it looks like it will only be momentarily on.


You could just wire the LED into the motherboard's PWRLED leads. Let the mobo do it for you.


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## Flava0ne (Dec 7, 2017)

I found this image while searching on Google:






I've tried both the Always On In & Out (Pins 1 & 4) where that just temporary momentary on then off. Nothing happens with the other 2. I guess I'm really going to have to splice/jump LED+ with the NO (Always On), but which one? In or Out?


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## Papahyooie (Dec 7, 2017)

Wire the always off line in and out to your PWRSW pins on the mobo. Wire the LED power line in and out to the PWRLED pins. Plus is in, minus is out.


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## Flava0ne (Dec 8, 2017)

Papahyooie said:


> Wire the always off line in and out to your PWRSW pins on the mobo. Wire the LED power line in and out to the PWRLED pins. Plus is in, minus is out.


That cycles the computer on then off constantly.


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## infrared (Dec 8, 2017)

Flava0ne said:


> That cycles the computer on then off constantly.


Sounds like you have the LED pins on the switch connected to the Power button pins on the motherboard instead of PWR LED. It's basically a closed circuit so the computer thinks you're holding your finger on the switch.

+ and - of the switch go to the PWR LED pins on the board, and whichever pair of pins you've found that are normally open and close when you push the button go to the Power switch pins on the board, which might be labeled as PWRSW or PWRBTN.


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## Flava0ne (Dec 8, 2017)

infrared said:


> Sounds like you have the LED pins on the switch connected to the Power button pins on the motherboard instead of PWR LED. It's basically a closed circuit so the computer thinks you're holding your finger on the switch.
> 
> + and - of the switch go to the PWR LED pins on the board, and whichever pair of pins you've found that are normally open and close when you push the button go to the Power switch pins on the board, which might be labeled as PWRSW or PWRBTN.


Thanks, you were right! I managed to get it to work properly now, thankfully I didn't burn out the LED on the switch lol.


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## infrared (Dec 8, 2017)

Flava0ne said:


> Thanks, you were right! I managed to get it to work properly now, thankfully I didn't burn out the LED on the switch lol.


Ah that's great news, well done


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