Power button

[jsb666]

hey guys, just a quick question what sort of button do i need for the power and reset buttons?

[OvRiDe]

For the most part I think about the only requirement is that they are "Momentary", which means that is only switch is only connected while you are pressing it. Other then that I think the skys the limit..

[tybrenis]

For the most part I think about the only requirement is that they are "Momentary", which means that is only switch is only connected while you are pressing it. Other then that I think the skys the limit..

OvRiDe is completely correct. I have used keyswitches... keypads... you may use whatever you please.

[jsb666]

thanks for the quick replys guys. thats all i needed to know :)

[xmastree]

Just a thought, If you like toggle switches you could use one switch for both.
Get a momentary, spco center off switch.
Switch it one way and release to turn on, the other way and release to reset.

[DaveW]

Just remember that you might need to be fiddling around for a while with those switches to make them work right. As a guy who's written a switch de-bouncing program in PIC assembler, and has a vague understanding therefore of how the motherboard sees the switch, you really want to make it as easy as possible: no matter what sort of switch you put in, all the motherboard wants to see is a simple Push-To-Make switch.

So although you can hook up pretty much anything as a switch-hell, even a thermistor can act as a switch, if you're that bored-you might need to do a little 'studio engineering' to get it to send the correct signal.

2 incredibly popular unusual switches: Key switches, like a car ignition, and missile-style toggle switches. You have any specific switches in mind?

-Dave

[xmastree]

As a guy who's written a switch de-bouncing program in PIC assembler, and has a vague understanding therefore of how the motherboard sees the switchGiven the cheapness of the switches on some cases, I imagine there's enough hardware debouncing on the motherboard to cope with most switches.

Know what would be cool? Reed switches behind the panel, and a magnet to activate them. Similar to what's used in a burglar alarm.

[DaveW]

Given the cheapness of the switches on some cases, I imagine there's enough hardware debouncing on the motherboard to cope with most switches.

Yeah, but not something like a toggle switch, which is really what i meant. And you'd have to be careful with 'novelty' switches as well, e.g. ones that remain stuck in for a set time and slowly depress.


Know what would be cool? Reed switches behind the panel, and a magnet to activate them. Similar to what's used in a burglar alarm.

It would make for some artistic and interesting setups, but anyone who comes anywhere near my computers with any kind of magnet, permanent or otherwise, suddenly discovers how difficult it is to hold a magnet without hands.

Although, magnetic switches could make for a completely button free front panel, which would be cool.

Reminds of a story my lecturer once told me; he knew a guy who, as an experiment, built a CPU out of relays instead of transistors. It started small, then took over the walls and ceiling. Every time the room was under stress, you could all the relays tapping away...i'd really love to see a CPU like that, it would be completely fascinating.

I think this was in the days of the 6502, when the transistor count was under a million. The 6502 only had 2300 transistors, if you can imagine that many relays, all up your walls, etc...must have been merry hell if one ever broke, or jammed...

-Dave

[xmastree]

Yeah, but not something like a toggle switch, which is really what i meant.You'd be surprised. Remember the old type AT power switches? Push on, push off which switch the mains to the PSU? I've successfully converted one of those to momentary action (by removing the bit of wire which latches it) and used it to power an AT board with a dual (AT/ATX) psu option. I just fitted an ATX PSU and wired the switch to the header as normal. It worked perfectly, and I'll bet that wasn't the cleanest of switches.


but anyone who comes anywhere near my computers with any kind of magnet, permanent or otherwise, suddenly discovers how difficult it is to hold a magnet without hands.Afraid of magnets? You must still be using floppies. :rolleyes: Gosh, how 20th century! ;)
Oh, don't place a motorcycle alternator rotor near the screen of a CRT. You'll have a daisy patterned shadow for weeks...


built a CPU out of relays instead of transistors.Like this? (http://upload.wikimedia.org/wikipedia/en/5/5c/Bombe-rebuild.jpg)

[OvRiDe]

Oh, don't place a motorcycle alternator rotor near the screen of a CRT. You'll have a daisy patterned shadow for weeks...
Sounds like experience talking there. Unfortunately I know exactly what you are talking about.. hahaha

[DaveW]

Magnet's can do more than just muck with your floppy discs, then can screw your Hard Drive over and they upset the alignment of the plates in a CRT monitor (although you can usually reset them with the Degasus function). Also they can cause harmful interference in all electrical systems, which, although usually minor, can be dangerous. You've probably noticed that the 2 main rules for an electronic appliance are that
1) Must not cause harmful interference
2) Must accept all interference, harmful or otherwise

I never really understood part 2, but your magnet could screw everything if you're not careful. The wireless card in my laptop went funny for a week after my brother left a torch with a magnet next to it. I thought it was completely buggered but it just started working again one day.

The relay CPU was actually integrated into the house, so it wasn't quiet like that. It was supposed to be that he just had the circuit boards on his walls and roof like wallpaper. Kinda what gave me the inspiration for the integration project, along with a zillion other things. What's that in the photo though? Looks awfully familiar, but i can't place it. Where have i seen it before?

-Dave

[jsb666]

You have any specific switches in mind?
Not really just going to go simple i think. This is going to be my first ever mod so im asking all the questions i need to get answerd before i start this e.g my thread about the wooden pc case in the Q&A page. then im going to use this mod as sort of a introduction into the modding world before i try something harder for my second mod. :D

[xmastree]

What's that in the photo though? Looks awfully familiar, but i can't place it. Where have i seen it before?
It's a replica of Alan Turing's Bombe (http://en.wikipedia.org/wiki/Bombe)

[DaveW]

Alan Turing i know. He came up with a really interesting, but difficult to get your head around, idea that proves that there exists data that cannot be computed. It was called the Halting Problem. I studied it last year, but to be honest, i still don't understand it. It's some sort of recursive problem, where if you have one program that stops a program when it completes, but the program it's monitoring is itself, then it gets stuck in an infinate loop, or if it's monitoring itself, it can never watch itself complete.

Jees, i come up with infinate loops all the time when i'm programming; who doesn't? All you have to do now is call them Turing Halts and you can get away with it ;)

-Dave

[amdmeplz]

i have one of those momentary toggle switches up for power down reset and center off ..... confuses the hell out of most ppl and it sucks when i hit and shut my computer down (it sits on the floor next to my desk) gets anoyying after a while..... but definatley makes ppl think (how the hell do i turn this on? )

[OvRiDe]

Magnet's can do more than just muck with your floppy discs, then can screw your Hard Drive over..
You are aware there are already powerful magnets inside your hard drives. We harvest them out of dead "out of waranty" drives all the time. Magnetic reed switches don't require powerful magnets to activate and it would only need to be in the near proximity of the computer for a few seconds while you are powering it on. Thats not even mentioning the high speed motor that spins the platters that uses electromagnetism to drive it.. If the platters are shielded enough to with stand those I think an small magnet outside the case would have a hard time interferring with the drive. Now the wifi card, I can definately see that.

[xmastree]

You are aware there are already powerful magnets inside your hard drives. We harvest them out of dead "out of waranty" drives all the time. They make great fridge magnets, don't they?

[crazybillybob]

I've Had a 3" tall 18" long "Refrigeirator" magnet on the side of my PC for 2 yrs now with no ill effect..... So Using a little one to boot the pc should't pose any problems.


Good Luck, I love the Idea of the stealth power switch :)

Crazybillybob

[onelegout]

Sounds like experience talking there. Unfortunately I know exactly what you are talking about.. hahaha
You realise that you can get rid of that using the 'degause' (sp?) or 'recall' setting on your monitor? right? ;)

[DaveW]

I've had one bad experience with magnets, i'm not risking any more! But i do agree that you could certainly do something interesting without buttons on your case.

-Dave

[Rankenphile]

I've heard you can get a similar feature using RFID. Probably a bit more expensive, but how cool would it be to wave a modded "magic wand" in front of your computer to turn it on?

[xmastree]

I've heard you can get a similar feature using RFID. Probably a bit more expensiveMaybe not... Know anyone who keeps cats?
Those electronic catflaps use a similar principle. The cat wears a small magnetic 'key' on the collar, tuned to a particular frequency. When it gets close to the door, the door senses it and unlocks.

[OvRiDe]

You realise that you can get rid of that using the 'degause' (sp?) or 'recall' setting on your monitor? right? ;)This is true .. but unfortunately older monitors didn't have that feature.. and my personal experience was a television.. :(


I've heard you can get a similar feature using RFID. Probably a bit more expensive, but how cool would it be to wave a modded "magic wand" in front of your computer to turn it on?Or how about when you just have to walk in the room with it. :)

Those electronic catflaps use a similar principle.Great idea!! I bet those could be very hackable!!

[crazybillybob]

Here's a kit from Parallax, it's not bargain basement but it's not to bad. Plus you should be able to get it to work with most Pic microcontrollers (like PicAxe or the KronosRobotics.com 's line of Microcontrollers, axtel line etc).

http://www.parallax.com/detail.asp?product_id=910-28142

I think I've see the reader for less but with out the tags.

There are also some Rf tag readers that run Via USB, but this wouldn't work to boot the PC, but would work for a login....If you can write the custom code you'd need.

Just keeping the Idea's alive!

Crazybillybob

[xmastree]

Plus you should be able to get it to work with most Pic microcontrollersThat's a complicated solution. Presumably it doesn't send any data until it detects a tag. So long as you don't need to identify a particular signal, you could just trigger a monostable from the data to avtivate the power switch.
That CD you bought, still has the anti-theft device on it? That would probably work.

[crazybillybob]

Ok,
Phidgets has a Usb model (here http://www.phidgets.com/index.php?module=pncommerce&func=itemview&KID=1144420836152.160.16.64&IID=48)
That when it reads a tag a led lights up, also has a connection for an external led. With a simple circuit (opto Isolator) and a relay that would do it. They sell just the reader and a kit with the reader and 6 button tags, 2 creditcard tags (think ID badges) and 2 keychain tags. They're out of canada so the reader is $65 CAD, the kit is $90 CAD which works out to $56.71 USD for the Reader and $78.51 USD Kit then add shipping.


Like I said just keep the Idea alive. Even if you don't use these someone else might like the info. (I know Dave is a Uber Pic Programer...so)


Good Luck no matter how you do it, it's still a cool Idea!

Crazybillybob

[Rankenphile]

You know, it's threads like this one here, where someone asks a relatively simple question that ends up launching a terrific debate and spawning awesome ideas, that really makes me love this forum. Great stuff, guys.

[xmastree]

And it highlights differences in our knowledge too. Dave is a PIC programmer, so he would use a PIC. I'm an electronic engineer so I suggested a hardware approach.
My favourite programming language is solder! :)

[crazybillybob]

There is a pretty good Article in the April 2006 edition of SERVO that goes over RF ID, and lists sevral Suppliers of Tagreaders and tag manf.

With all these diffrent Backgrounds we should be able to work together and make some thing work :)


Crazybillybob

[antheh]

I done a mod to my old case where I removed the power switch and reset switch from where it originally was (on top of the case which ****ted me) and moved it to lower side of the from of the case. I just used toggle switched SPST I thing would be the proper term for the switch I used. Single Pole Single Throw.