Wiring an Otis Elevator Button

Thread Starter

montanamae

Joined Jan 28, 2019
4
Hi All About Circuits,

So I am wonrking on a project involving an an illuminating 24V, concave flush, 4-pin amp connector OTIS elevator button with a mirrored stainless steel front, a clear ring body and a white LED colour.So far I am able to wire up the positive and negative pins in order for the light to be permanently on, but ultimately I want to be able to push the button to turn the light on, and either let it stay on and time out after about 15 seconds, or push again to turn it off. I am aware that I will need a delay of some kind and have been looking into both time delay relays, as well as latching relays.

Does anyone have an idea of how this circuit might look like? I have to finish this project fairly soon and would appreciate any help or suggestions that I can get.
 

Thread Starter

montanamae

Joined Jan 28, 2019
4
A 555 flip/flop should do it, is that the only function you want for an elevator?
Max.
Thank you Max, I will look into this. It is for a display that is meant to represent an elevator fitting that is currently in a built project.
 

Thread Starter

montanamae

Joined Jan 28, 2019
4
Is there a simpler way that involves as few wires as possible? Perhaps something that does not involve a breadboard?
 

MaxHeadRoom

Joined Jul 18, 2013
18,872
A Interval On timer is one way, some timers are configurable as to function.
The Interval On switch's when energized and stays on for the programmed period.
Max.
 

crutschow

Joined Mar 14, 2008
23,158
I want to be able to push the button to turn the light on, and either let it stay on and time out after about 15 seconds, or push again to turn it off.
Do you want it to do both, i.e. if you push the button a second time, before the 15s is up, the light is turned off?
 

Sensacell

Joined Jun 19, 2012
2,430
Is it ok if the light fades off at the end?

Then a very simple circuit with an N-Channel MOSFET could do it.
 

Thread Starter

montanamae

Joined Jan 28, 2019
4
Do you want it to do both, i.e. if you push the button a second time, before the 15s is up, the light is turned off?
I was hoping to create two options. So one would be the light switches off after 15 seconds and the second option would be push the button again to turn the light on. The start of both would be that the light only turns on when you push it which it currently is not doing.
 

crutschow

Joined Mar 14, 2008
23,158
Below is the LTspice simulation of a circuit that should do what you want, using two MOSFETs and a few resistors and capacitors.
When switch S2 is open (red trace low), momentarily pressing push-button switch S1 (blue trace) gives a 15 second ON time (yellow trace).
When S2 is closed (red trace high), the circuit acts with an alternate on/off action each time S1 is momentarily pushed.
Pot U1 is used to adjust the one-shot time.
If that time isn't critical, you can replace the pot with a 70kΩ resistor.
The maximum load current is about 0.5A with the BS250 MOSFET.
A higher current transistor can be used if the load is more than that.
The circuit can be built on a small perfboard.

upload_2019-1-30_12-48-7.png
 
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