Sign in with
Sign up | Sign in
Your question

Convert toggle power switch to momentary?

Last response: in Systems
Share
April 17, 2010 10:27:45 PM

Hey guys, I'm building a case mod for my machine, and I'd really like to use a rocker switch (toggle, i believe), rather than the standard momentary power switch. I would imagine that there is a way to use a rocker switch, however, in place of the momentary switch.
I can solder, and follow directions, but I don't know enough about circuits to build my own-- do any of you have any ideas on how to do this?
Related resources
April 18, 2010 3:30:13 PM

If you mean to use a rocker switch where up is on and down is off, that isn't going to be easy. If you just replace the momentary push button with a momentary rocker, it's essentially the same switch in a different form. That wouldn't really make sense unless you just like the appearance of a rocker switch. If you're after the first scenario, you'd need to use some logic gates to sense when the +5V line has (and doesn't have) voltage to get your two specific functions (on & off) the switch would perform. You could power the circuit off the 5 VSB line and use an optical relay to connect to the motherboard header to turn the computer on and off.
m
0
l
April 18, 2010 5:57:16 PM


I like these switches- specifically the LED rockers, but if I use them as my power switch they won't work...It'd be like if I held the power button for 5 seconds.


Don't these return to the "off" position, as if the were spring loaded? What I'm going for is something similar to the old AT power supply style switch.

Orion1024 said:
If you mean to use a rocker switch where up is on and down is off, that isn't going to be easy. If you just replace the momentary push button with a momentary rocker, it's essentially the same switch in a different form. That wouldn't really make sense unless you just like the appearance of a rocker switch. If you're after the first scenario, you'd need to use some logic gates to sense when the +5V line has (and doesn't have) voltage to get your two specific functions (on & off) the switch would perform. You could power the circuit off the 5 VSB line and use an optical relay to connect to the motherboard header to turn the computer on and off.

Logic gates? Those would be a type of circuit? So when I flip the switch on, it detects if there is power on the +5V line. If there isn't power, then it... does the same thing that the momentary switch does? Connect the two wires? If there is power, then it acts as if it was off (not connecting the wires)?
What sort of pieces would I need for this circuit, besides the switch?


Maybe i should be a little more clear about my goal, if you guys have other insight?
Ultimately, I have 4 devices, and I'd like a row of 4 identical switches- the other 3 devices require toggle switches, while the PC is the only one that requires a momentary switch. I think it would look odd to have the computer's switch be off while the others are on, yeah?
m
0
l
April 18, 2010 6:29:26 PM

What I'm saying is if you want to have a rocker switch where only up will turn the computer on and where only down will turn it off. It would not be a momentary switch, so the switch stays either up or down. Say the computer is off and you flip the switch up...the AND gate would need one input to be low (the 5V line, input held low by a resistor) because it's inverted and the other to be high (the 5 VSB from the switch) to trigger it's output and turn the computer on. Once the computer turns on, the 5V line would be high so the AND gate shuts off it's output. Similarly, you are using a second AND gate just to turn the computer off. If you used a momentary rocker switch with no logic circuitry, then pushing up once would turn the PC on, pushing up again would turn it off, and down would have no purpose (or be identical in function). Yes, a logic gate is an integrated circuit like an AND, OR, XOR, inverter, etc. Usually there are four to six complete logic gates in one IC. You could do it with a two input AND and an inverter on one of the inputs of the second AND. Of course there's more to it than just that. I'm just an amateur with electronics, so maybe an electrical engineer will help you out here. My advice if you are interested in this sort of thing, is to pick up some basic parts like logic gates, a power supply, and a decent beginners book and just do some experimenting. The parts won't cost you very much.
m
0
l
April 25, 2010 8:14:17 PM

I actually found a solution on another site- if I just solder a small capacitor in the loop, it allows current to flow through the headers for a short time- effectively acting as a momentary switch. Then I just "shut down" teh computer instead of flipipng hte off switch. I've tried it, and it works. Thanks for the help though!
m
0
l
June 5, 2011 1:16:20 AM

Robanada said:
I actually found a solution on another site- if I just solder a small capacitor in the loop, it allows current to flow through the headers for a short time- effectively acting as a momentary switch. Then I just "shut down" teh computer instead of flipipng hte off switch. I've tried it, and it works. Thanks for the help though!


Hey, I'm doing something very similar. i'm building an arcade, and everything will be running on a smart power strip, so that once the computer turns on, everything else (monitor, marquee, speakers) turns on. i want an external mounted rocker to replace the pc power button. where did you find this capacitor (what kind) and how easy was the installation?
m
0
l
June 5, 2011 2:14:48 AM

GuyneO said:
Hey, I'm doing something very similar. i'm building an arcade, and everything will be running on a smart power strip, so that once the computer turns on, everything else (monitor, marquee, speakers) turns on. i want an external mounted rocker to replace the pc power button. where did you find this capacitor (what kind) and how easy was the installation?


Hah, the capacitor had fallen off of a GeForce 6600 video card, and I was saving it to solder back on. Instead, I soldered it to the switch- it was fairly easy to do, actually...just soldering a few wires in the right places :) 

I don't know how you'd do it with the power strip, but I'll bet you could use a bunch of relays to turn each thing on.
m
0
l
June 5, 2011 4:41:37 AM

It's idependant of the strip. I'm going to cut the wires leading from the motherboard to the power button, extend them about 6 feet, and have it connect to an LED rocker on the outside of the arcade cabinet. the power strip is just something cool to help it all work together, but isnt related to my issue.
m
0
l
!