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| krick:
More interesting stuff that someone might find useful: I found a thread where a guy mentions using a 4.7uf capacitor across the power switch. Then he mentions that some motherboards don't work with a capacitor and then goes on to describe a circuit that will work by tapping 5V off of the "wake on lan" header that is present on most modern motherboards. Later in the thread, he discusses other solutions involving relays, zener diodes, and/or 555 timers: http://lists.exploits.org/ups/Feb2003/00018.html http://french.moren.ca/~kenm/cct/index.html http://lists.exploits.org/ups/Feb2003/00019.html I've quoted the complete text below for your convenience... --- Quote ---Hi All... I'm new to the list. I've been a Linux/Unix sysadmin for several years, but my main background has been electronics/hardware. recently I installed NUT for a client and ran into a problem with his hardware, namely, his ATX motherboard had no provision to auto-startup after a power failure: no jumper; no BIOS setting. Experimenting on a few of the machines I had sitting around, I found that connecting a 4.7uf. capacitor across the power switch connector on the motherboard did a fine job of simulating a momentary switch closure. It would be best to use a non-polar capacitor (hi-K ceramic or mylar) to save having to discover what the polarity of the switch connector is and avoid a polarity mismatch. However, in this case it did not work on my client's system, whose motherboard was one of the small percentage which require a short delay before applying the switch closure :-( So I developed this circuit: http://french.moren.ca/~kenm/cct/index.html Hope it works for you if you need it... Regards, Ken Charles Lepple wrote: >Out of curiosity, did you look at feeding the wakeup signal back through >the WOL port? At first glance, I'd say that you could get by with just a >555 timer and 3 or 4 passive components, but I'll readily admit that I >haven't taken a look at this in any great detail. > > I had not thought of trying to use that at the time, however I expect I would run into the same issue, that of needing a delay after powerup. Not knowing the specifics of the WOL interface standard, I didn't go there... For most motherboards, the simple capacitor suffices. My circuit was based on what I had at hand. Certainly with a little ingenuity, one could probably build a working device around a single 555... I didn't have one handy. With the 4528, which I did have, it was relatively easy: the first one-shot to set the delay; the second to set the output pulse length. I used the little relay because I had it, and to eliminate any polarity issues at the motherboard power-on connector. If one used the relay with a 555 to provide the delay, they could use it to switch in a capacitor to the motherboard connector as in the simple solution... in that case you could eliminate many of the components of my circuit as the 555 could drive the relay directly without the buffering transistor that I used. A 555 used as a one-shot uses one more capacitor than its 4528 equivalent. It may not have the problem that the 4528 has of delivering an immediate power-on output pulse in addition to the delayed pulse, which I devoted two capacitors and a resistor to solving. Thinking about it now, I can visualize a circuit using a resistor, two capacitors, a zener diode and the relay that would do the job, if we wanna talk "minimum component" ;-) --- End quote --- |
| SirPeale:
--- Quote from: krick on June 15, 2004, 11:36:22 pm ---On the other hand for those of us who need to use Windows.... --- End quote --- The only reason to use Windows that I can think of (unless you're using another emulator that is Windows only) would be sound driver issues. There aren't many DOS sound drivers for current stuff. Unless they hide really well. |
| SoundDoc:
Haven't built it up to test yet. Just did it on a coffee break, so its pretty rough, but this should do the job. Decided to steal power from the WOL header instead of a wire from the PS connector, just makes it a bit neater. And I was just going to use a transistor to switch the power connector, but this way its fully isolated from the pc and can't hurt anything if you build it wrong. (well, it could hurt you ;) ) Some MB's also have the 5v standby power availiable on a pin on the MB header, so you could get it from there as well. If I get a chance tonight, I'll throw one together and test it out. I've got to do something while I wait for the paint on my cab to dry..... ;D SD *edit* deleted the pic as it REALLY messed up the thread..... ;) look futher down for the updated circuits...... |
| krick:
--- Quote from: SoundDoc on June 16, 2004, 11:57:26 am ---Haven't built it up to test yet. Just did it on a coffee break, so its pretty rough, but this should do the job. Decided to steal power from the WOL header instead of a wire from the PS connector, just makes it a bit neater. And I was just going to use a transistor to switch the power connector, but this way its fully isolated from the pc and can't hurt anything if you build it wrong. (well, it could hurt you ;) ) Some MB's also have the 5v standby power availiable on a pin on the MB header, so you could get it from there as well. --- End quote --- You are the man. I can't wait to get some parts together and give it a try. I hadn't thought about the need for 5V of standby power. Do all current motherboards have WOL connectors? Do PS/2 keyboard connectors supply 5v standby? I think some USB ports do. If you can get this design polished and it works well, you might want to talk to someone about getting some boards made. I'm sure you could sell them. |
| SoundDoc:
Lots of new motherboards do have the WOL connection, as do most atx style older ones. If the MB has onboard Lan though, they usually leave it off. its hit or miss otherwise. Some have it on the main button header, others if they have power on KB always power the ps/2 keyboard port, and some do provide it on the USB connectors, usually with a jumper But you can always find it on the MB power conector. Some people though I don't think are confident/savy enough to solder/splice into their motherboard, so I threw the WOL connector possibility out there so you wouldn't have to modify the MB or PSU. What MB are you using? I'll take a look and find the best place to get it from. SD |
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