Howdy Ya’ll! I have an interesting question that has me a little stumped. I have never really been able to grasp the function of a 3-way switch very well. I have a customer looking to use a pushbutton switch as a 3-way. Anybody know if this is possible and how it might work? The customer is currently using switch 432-1212-ND and would like to at least keep this style if possible if not use this very switch.
Is this for a guitar pedal? or for AC power?
Here are the basic ways to wire up a three way switch pair
In the traveler system, also called the “common” system, the power line (hot, shown in red) is fed into the common terminal of one of the switches; the switches are then connected to each other by a pair of wires called “travelers”, and the lamp is connected to the common line of the second switch, as shown.
The “California 3-way” or “Coast 3-way” connection never connects the lamp socket shell to the line (hot) terminal. An optional additional lamp can be connected at Terminal A as a pilot lamp, or to illuminate a long corridor. An optional receptacle can be connected at Terminal B, since that terminal is always live.
Wikipedia Source page
This is for AC power.
The SPST switch will not work in a three-way configuration. A SPDT in an ON-ON style will work. You will need two of these switches where you basically connect the NC to NC and NO to NO, then one common becomes the input and the other common becomes the output.
The footswitches the customer is looking at will not be able to handle AC loads, they can be used as controls for mechanical relays or solid state relays, in which case two SPDT wired in a three way switch configuration like John mentioned would work.
At that point you can just use two momentary switches as control signals for a microcontroller. When pressed, if the circuit is on, turn off, if circuit is off, turn on, in that case a off-momentary switch can be used, but based on their question they’re unlikely to be seeking an embedded project out of this.