The title is it in a nutshell
I've got an antique knife switch that I'd like to use to power up (and down) an embedded PC.
The PC power switch is essentially two wires, a ground and +5v (measured with a voltmeter). Normally, a momentary pushbutton is used. You press it for a short time and the PC powers up. Press and hold while the PC is on and it powers down.
I'd like to use a knife switch, so the action would be
1) knife switch disengaged, pc is off 2) engage knife switch, PC powers up, which required a +momentary+ contact, but the knife switch is a constant contact. 3) PC is on while knife switch is engaged. 4) disengage knife switch, PC powers down, which requires another momentary contact, but a little longer duration.
I've found a simple circuit with a 5v reed relay and a 470uf capacitor that could work.
I was really hoping to only connect the circuit to the PC's power switch wires, and not require a separate power supply line.
Is something like that even possible?
EDIT I don't believe I can add images to the comments so I'm adding the circuit I mention below here. I was mistaken about the 2 capacitors though. It's two relays to control 2 separate buttons, one for the engagement of the toggle, and one for the disengagement.
see this post
I originally thought I could use something like this, till I realized I'd have to run a completely separate power (and possibly ground) line for it.
I +could+ run the additional lines. I'm really just wondering if the circuit I'm describing is even possible. It seems like it should be, but my EE background is pretty limited.
EDIT: Switch is SPST.