NO/NC switch

[ms2004]

Evening,

My friend has aquired a pedestrian crossing "Wait" push button unit. He wants to put it in his garden, but I dont know enough about wiring it and he knows even less.

The push button simply connects to a NO/NC microswitch. He wants to be able to hit the button and turn the light on and hit it again to turn it off. I dont think this is possible with a NO/NC switch is it?

Can it be wired in such a way that it becomes possible or will the switch need to be changed? I assume it must be but wanted confirmation.

TIA.

 

[EFLImpudence]

It doesn't look like it.

NO - Normally Open - Off when at rest.
NC - Normally Closed - On when at rest.

It sounds like a 'momentary' switch - that is, it is only on while you press it so will turn off when released - or vice versa.

 

[ms2004]

Yes, you're right, thats how it works. I assume there is something in a traffic light that keeps it on until the traffic light goes red. Doesnt matter, we can just wire it up to a plug and he can use it like a normal light. Thanks for your help.

 

[EFLImpudence]

You might be able to get a switch that switches on then off with alternate presses.

There are all sorts about.

 

[AndyPRK]

dunno what voltage the light is, maybe the WAIT sign could be lit up from a switch inside the house

 

[securespark]

Yes, you can do that, but it would need a relay.

I have done the same in my kids' bedrooms with a 24V relay and PTM switches.

Can dig out an old relay if you like and look at the way I wired it.

What voltage are the lamps in "the light"?

 

[ms2004]

Yes, you can do that, but it would need a relay.

I have done the same in my kids' bedrooms with a 24V relay and PTM switches.

Can dig out an old relay if you like and look at the way I wired it.

What voltage are the lamps in "the light"?

Yes please, Thanks very much, voltage is 24V.

 

[securespark]

 

[securespark]

OK.
1 & 2 are 230V in to transformer and looped from there is N out to the lamp(s) and 230V live to the relay terminal 14.
Terminal 11 is the 230V output switched via the 24V-fed PTM through the coil.

The 24V -ve output from the transformer goes to A2.
The 24 +ve output from the transformer goes to one side of the PTM switch.
The other side of the PTM switch goes to A1.

So you have 24V from the tx feeding the relay coil through the PTM switch. When briefly energised by the PTM switch, the relay connects terminals 14 and 11, sending a 230V feed to the lamp(s) - via a local transformer of course if the lamps are 24V.

When you hit the PTM switch again, the lamp(s) extinguish.

 

[securespark]

The only thing is, I can't see a part number for the relay!

 

[securespark]

I got them from here, but it was a good few years ago, so whether they still stock them, I'm not sure.

https://www.willow.co.uk/

 

[FrodoOne]

Evening,

My friend has aquired a pedestrian crossing "Wait" push button unit. He wants to put it in his garden, but I dont know enough about wiring it and he knows even less.

The push button simply connects to a NO/NC microswitch. He wants to be able to hit the button and turn the light on and hit it again to turn it off. I dont think this is possible with a NO/NC switch is it?

Can it be wired in such a way that it becomes possible or will the switch need to be changed? I assume it must be but wanted confirmation.

TIA.

What may be needed is a "Push-On/Push_Off Switch" or a "Push Button Latching On Off Switch"

See https://www.amazon.com/s?k=push+but...992860&tag=googhydr-20&ref=pd_sl_87uxdjd3np_b

If you look up "Push On - Push Off Relay" (or words to that effect) you will find many "electronic" ways to accomplish this, such as https://www.circuitlib.com/index.php/schematics/product/100-push-on-push-off/category_pathway-35

If operating on 24 V, you would need to provide a 12 V DC power supply for the above circuit from the 24 V but the voltage switched would depend on the contacts of the relay chosen.

 

[bernardgreen]

I assume there is something in a traffic light that keeps it on until the traffic light goes red.

There is a box of electronic ( or electro-mechanical ) logic somewhere near the traffic lights that controls all the lights including all the "Cross Now" lights. The switch in the "Wait" button is connected to an input to the logic.

As already mentioned a relay is needed.

To simulate the function all you need is a time delay relay that is trigger ON when the button is pressed. This turns the WAIT lamp ON and then after the time delay expires the relay drops OFF and the WAIT light goes out.

For a simple DIY project I would use this delaid Off relay. If the lamp is 230 volts then this and a suitable housing is all you need. It may even fit inside the WAIT lamp housing.

https://uk.rs-online.com/web/p/timer-relays/8966822/