LED's in Momentary Push Button Switch 1NO1NC

Thread Starter

Brandon Hunt

Joined Oct 7, 2019
2
I apologize if I am posting this in the wrong section.

I have a 12v project I am working on, which has 2 momentary 1NO1NC switches with build in Led's(these to be exact (https://tinyurl.com/yytmp2qs)

I can wire them so that the led lights up when the button is pressed, that's simple enough. What I am wondering, is there a way to wire it so that if one is pressed, it not only turns its led on, but also turns the other one off?

So basically, if I push "button 1" it lights up, if I then push "button 2" it lights up, but also turns off "button 1's" light, and so on.
 

eetech00

Joined Jun 8, 2013
1,726
I apologize if I am posting this in the wrong section.

I have a 12v project I am working on, which has 2 momentary 1NO1NC switches with build in Led's(these to be exact (https://tinyurl.com/yytmp2qs)

I can wire them so that the led lights up when the button is pressed, that's simple enough. What I am wondering, is there a way to wire it so that if one is pressed, it not only turns its led on, but also turns the other one off?

So basically, if I push "button 1" it lights up, if I then push "button 2" it lights up, but also turns off "button 1's" light, and so on.
Hi

Since if they are momentary buttons, something has to remember which button was pressed.
This can be a circuit done a number of different ways (relays, Flip Flop, different PB's).

How much current does the PB's need to support?

eT
 

ci139

Joined Jul 11, 2016
799
Simulation link -- provides a most likely internal wiring diagram for SPDT (what it actually is)
.
! Beware of the connections at upper-rightmost diagram (the NC (a normally closed) is N/C (not connected although the wire is drawn over it ) )

. Notice the tiny script " no cathode and anode distinction " below topmost ccw rotated back mount image

.
you can't achieve the function you describe . . .
. . . although you can achieve a slightly different function (without your "etc." switch)
(" .txt " to Falstad, Menu, Import from Text)
((there is the 5-th "-Led" pin reassigned for the lower button (below↓) ))
.
Fancy Knobs Interactive.png
 

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Bhunt83

Joined Sep 15, 2019
12
Ok, that’s the voltage. How much current do the PBs need to support?
that I am not sure. These are being used to replace 2 momentary buttons that were already on a board, 1 for on, 1 for off.

the goal was just to use a button with a visual(led) indicator, as the original board didn’t have anything visual. The board is for a wireless light switch, one switch is connected to the top “on” the other to the bottom “off”
 

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djsfantasi

Joined Apr 11, 2010
5,704
that I am not sure. These are being used to replace 2 momentary buttons that were already on a board,..,
And therein lies the problem. No reliable alternative can be proposed without knowing the PB current rating. Typically, if you use a replacement that doesn’t match the existing PB current rating you run the risk of a massive failure. Such as fire.

Do you have a schematic? Can you identify a part number? Anything to determine the current rating.
 

Bhunt83

Joined Sep 15, 2019
12
And therein lies the problem. No reliable alternative can be proposed without knowing the PB current rating. Typically, if you use a replacement that doesn’t match the existing PB current rating you run the risk of a massive failure. Such as fire.

Do you have a schematic? Can you identify a part number? Anything to determine the current rating.
Would any of this give that information?
 

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Bhunt83

Joined Sep 15, 2019
12
Simulation link -- provides a most likely internal wiring diagram for SPDT (what it actually is)
.
! Beware of the connections at upper-rightmost diagram (the NC (a normally closed) is N/C (not connected although the wire is drawn over it ) )
.

.
you can't achieve the function you describe . . .
. . . although you can achieve a slightly different function (without your "etc." switch)
(" .txt " to Falstad, Menu, Import from Text)
((there is the 5-th "-Led" pin reassigned for the lower button (below↓) ))
.
View attachment 187527
is there a different type of led push button that would achieve the function?
 

ci139

Joined Jul 11, 2016
799
? You only have 10 fingers . . . if you randomly play with light switches then each next complex response to cover pushes the design away from simple wiring of button contacts

e.g you can do/achieve everything at any possible way -- only this "possible" defines the requirements for each

if i remember right the aim was to break each prev. button on next press . . .

there might be such buttons . . . indeed

/// but if you complete "the circle" and lift of your finger from button pressed before the others (and then same for next , etc) ← then that sets a requirement for new extra feature -- eigther to be avail. off the shelf -- or to be achieved by modding the construction of the button -- or adding the complexity of the control circuit

/// usually you go by your daily routine and switch the lights you need -- and do not create repair challenges (by time , engineering skills -- or the very availability of the spare parts on a market after couple of years ...)
= make everything - for dayly use - as simple and std. as possible with the least number of modifications
 

djsfantasi

Joined Apr 11, 2010
5,704
Buttons arranged like this are referred to as “radio buttons”, for the tuning buttons on old car radios.

They are hard to find, especially in custom configurations. But you can find circuits online that make standard buttons into radio buttons. Google “radio button circuit”.
 
Get two double-pole, double throw (DPDT) illuminated pushbuttons. They can be cross wired several ways to exclude each other, one excludes the other, etc. The key is the DPDT configuration.
 

Yaakov

Joined Jan 27, 2019
1,604
This is a perfect application for a small PIC, though I am not entirely clear what will be used to toggle the change. It can’t be the switches themselves, because that would only indicate the switch had been pressed, not, as I presume is desired, the state of the device they control, authoritatively.

The specification is a little confusing, to be honest.
 
Isn't the original question basically just an SR latch? Put a pullup on each pushbutton. Switch to ground. Then one button to the S input and the other button to the R input. LEDs or drivers attached to the Q and /Q outputs.
 
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Thread Starter

Brandon Hunt

Joined Oct 7, 2019
2
Isn't the original question basically just an SR latch? Put a pullup on each pushbutton. Switch to ground. Then one button to the S input and the other button to the R input. LEDs or drivers attached to the Q and /Q outputs.
I tried to draw it out to show what I was explaining. Attached

Basically this circuit functions fine. The on button turns it on, the off button turns it off. This only issue is with the LED's inside the button. Currently I just have +12v connected to them, so the internal light is always on.

What I was hoping to accomplish was that the light inside the button is only on, if thats the button currently pressed(IE button 1's(on button) internal light is on when pressed, but if you press button 2(off button) then its internal led would come on, but also button 1's(on button) would turn off)
 

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ci139

Joined Jul 11, 2016
799
? but this is the wiring scheme "Program 1" ( refer to fig. #3 ) or try with Simulator ( ← toggle the _,\,_ Shape left of the blue led)

PS! actually the LED of your Button is wired inside a full bridge rectifier (= Polarity dont care) so basically you only need to apply 12V drop of either polarity to LED terminals (the uppermost and the lowermost contact on the back of the button ↑ fig. #3 ↑ )
___
? if you need Led ON at contact Brake use the wiring as shown below (Simulation)
BL-MF-TB.gif
 
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Tonyr1084

Joined Sep 24, 2015
3,674
I tried to draw it out to show what I was explaining. Attached

Basically this circuit functions fine. The on button turns it on, the off button turns it off. This only issue is with the LED's inside the button. Currently I just have +12v connected to them, so the internal light is always on.

What I was hoping to accomplish was that the light inside the button is only on, if thats the button currently pressed(IE button 1's(on button) internal light is on when pressed, but if you press button 2(off button) then its internal led would come on, but also button 1's(on button) would turn off)
So whatever your circuitry is doing - you're happy with that. The issue you're having is with the push button LED's.

Well, I haven't fully studied the question and goal, but it sounds to me like you want to see which button was activated by its internal light. I'm assuming you already have these lighted pushbutton switches. We'd need to know how they're wired internally. They're pretty basic in that there's a resistor and an LED preset to a factory value, probably around 15 to 20 mA for the internal LED. What we don't know is how the LED is connected to the two, three or four (or more) switch leads. That may help us help you. Can you post a picture of the switch? Both the front and the back ends.
 

eetech00

Joined Jun 8, 2013
1,726
that I am not sure. These are being used to replace 2 momentary buttons that were already on a board, 1 for on, 1 for off.

the goal was just to use a button with a visual(led) indicator, as the original board didn’t have anything visual. The board is for a wireless light switch, one switch is connected to the top “on” the other to the bottom “off”
hi

We need to see a schematic of the circuit.
That would eliminate a lot of guess work.
Do you have a part number and mfg for the wall switch so we can maybe find a schematic. If not, the only other thing to do is trace the PCB and make one...

eT
 

Bhunt83

Joined Sep 15, 2019
12
So whatever your circuitry is doing - you're happy with that. The issue you're having is with the push button LED's.

Well, I haven't fully studied the question and goal, but it sounds to me like you want to see which button was activated by its internal light. I'm assuming you already have these lighted pushbutton switches. We'd need to know how they're wired internally. They're pretty basic in that there's a resistor and an LED preset to a factory value, probably around 15 to 20 mA for the internal LED. What we don't know is how the LED is connected to the two, three or four (or more) switch leads. That may help us help you. Can you post a picture of the switch? Both the front and the back ends.
currently I just have them wired as shown here...https://forum.allaboutcircuits.com/attachments/wire-png.188244/

this just has them lit up completely until/if I found a better way.
 
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