Need help with spst toggle to momentary

[SJones]

I'm working on a car project moving electronics over to a different car, however the original uses a momentary switch for the headlight while the other uses a toggle.

I have seen ways to make a spdt toggle switch into a momentary one using a capacitor and a relay but thus far struggling to find a simple way to turn the spst switch into one.

Can anyone suggest the simplest way to achieve this, it needs to send a signal pulse for both directions, for on and off (essentially a voltage change from 12v to 0v or 0v to 12v)

 

[danadak]

Is this a switch where you want to press it once, it stays on, until you press
it a second time, and it goes off and stays off ?

Or one where you press, stays on as long as you keep pressing, and when
you stop pressing it goes off, stays off.

Regards, Dana.

 

[SJones]

So, it's the 3rd option, the wiring that's in the car now is expecting the first option, you press it once and returns to normal position, keeping the lights on, so a momentary switch, the body control module works out if they are already on or not and switches it over.

but the stalk that it is being adapted to is a toggle, so the second option, you press the switch and stays in it's location keeping the lights on until you press the switch back(you just don't need to hold it)

so I need to replicate the first, where you press and release and the lights stay on, until you press it again, I know that there would be no way to know the position of the stalk and that at times the switch may be flipped, but I'm not concerned about that bit

 

[danadak]

Latching relay and momentary push button then would suffice.

https://www.mouser.com/datasheet/2/357/105A_755-7090.pdf

Regards, Dana.

 

[eTech]

So, it's the 3rd option, the wiring that's in the car now is expecting the first option, you press it once and returns to normal position, keeping the lights on, so a momentary switch, the body control module works out if they are already on or not and switches it over.

but the stalk that it is being adapted to is a toggle, so the second option, you press the switch and stays in it's location keeping the lights on until you press the switch back(you just don't need to hold it)

so I need to replicate the first, where you press and release and the lights stay on, until you press it again, I know that there would be no way to know the position of the stalk and that at times the switch may be flipped, but I'm not concerned about that bit

HI

So....forget about the mechanical action of the switch for moment. Let's discuss the electrical requirement for the signal that controls the headlights on the "different" car.

1. Does the control signal need to remain at 12v for the lights to "turn on" and "remain on"?
And the lights "turn off" and "remain off" if the 12v signal is removed?

Or,

2. Do the lights "turn on" and "remain on" if a 12v control signal is temporarily applied, and then removed?
And the lights "turn off" and "remain off" if the 12v control signal is temporarily applied, and then removed again?

Number 1 above is a "steady" input signal.
Number 2 above is a "pulsed" input signal.

 

[crutschow]

I need to replicate the first, where you press and release and the lights stay on, until you press it again, I know that there would be no way to know the position of the stalk and that at times the switch may be flipped,

Okay.
Below is the LTspice sim of a circuit that does the above from a toggle switch input:
It uses CD4093 CMOS logic gates (4 gates in one package) configured as an XOR gate to generate an output pulse (red trace) on both the closing and opening of the toggle switch (green trace).
The toggle switch is simulated by the STog switch.

Vbat is the 12V power from the ignition switch.

You can build the circuit on a small perf board.