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Using a keypad to turn a computer on???

S

skandaluz

[H]ard|Gawd
Joined
Jun 23, 2004
Messages
1,305
Hi, out of curiousity, has anyone ever done or know anyone who has used a programmable keypad to power on a computer? Sorta like the keypads on safes and such. Why i'm asking is that i thought it could be a fun mod to do to where you punch in the code and your computer would turn on?
 
Actually lots of motherboards support this abillity to do so. If you enter into the Bios of those boards and go to power managment its normally there where you can bind/make a button for turn on of a pc from the keyboard.
 
yea, i knew about that but what i actually wanted was an external keypad to replace the power button
 
Edit because I hit reply then went afk to grab a snack and then my post became moot point.

Also, let me know if you find one you don't have to build. Not too handy with electronics.
 
When you do this, you must take into consideration case security. If anyone can unscrew a couple screws and get into your case then the keypad security is completely superfluous, as anyone could just disconnect the keypad and short the poweron header normally. Though if you are just doing this for shits and grins and not for actual security of any kind then disregard this. And if you are doing this for security, then there are much better ways of securing a system than having a keycode to turn the system on.
 
jpmkm said:
And if you are doing this for security, then there are much better ways of securing a system than having a keycode to turn the system on.
Click to expand...

Weld it shut and wrap steel chains around it.
 
jpmkm said:
When you do this, you must take into consideration case security. If anyone can unscrew a couple screws and get into your case then the keypad security is completely superfluous, as anyone could just disconnect the keypad and short the poweron header normally. Though if you are just doing this for shits and grins and not for actual security of any kind then disregard this. And if you are doing this for security, then there are much better ways of securing a system than having a keycode to turn the system on.
Click to expand...
He just wants to use a keypad instead of a button, not to secure the case. There's lots of keypads you can use but you'll have to get one thats got a timer and relay built in and you'll have to power it some way most of the stand alone keypads I've put in can use either 24VDC or 12VDC you might have to mode the connector for the keypad but that should be easy.
 
OkI found somthing that will give you an idea what you will needand look for I'm not saying you should use this but it will be similar to what you will need.
Keypad
 
Ski Me said:
He just wants to use a keypad instead of a button, not to secure the case. There's lots of keypads you can use but you'll have to get one thats got a timer and relay built in and you'll have to power it some way most of the stand alone keypads I've put in can use either 24VDC or 12VDC you might have to mode the connector for the keypad but that should be easy.
Click to expand...
I wasn't talking about using the keypad to secure the case. I was just saying that if he didn't secure the case(physically) then the keypad would be quite trivial to bypass, thus defeating the purpose of having a keypad.


edit: anyway, if I was doing this, I'd probably just hack up an old touch-tone phone and put a bit of logic in front of it.
 
Yea, i'm just doin for this for kicks and nothing more. :)

Thanks Ski Me. Thats pretty much what i was looking for.

Now where would i be able to get one anyways?
 
It's not that hard. The trick is that keypads like you're describing multiplex the keys over rows and columns, so you'll need to scan the keyboard to watch for a keypress. I think the easiest way to do it would be to connect the the keypad to a microcontroller. That'll use four outputs (columns) and three inputs (rows).

You'll also want to have the microcontroller control one ouptut line which will trigger a FET or relay in parallel with your case on/off switch. I guess you'll want to monitor the power good signal from your power supply, so the board knows when the computer is off or on. You can run the keypad circuit from standby power.

Then, it's a matter of writing the software for the microcontroller.

The microcontroller scans and watches keypresses. After the fourth keypress, it looks at the keys entered and compares them to the correct code. If the code is correct, it unlocks. Otherwise, it resets the key count to zero and stays locked.

You can write software to control an LED or two so that when unlocked, you can enter and store a new code. Maybe escaping it with a special key, so that *1234 when unlocked sets the key code to 1234.

When a correct code is entered, the microcontroller can close the FET or relay for half a second to get the power supply started.

So, you'll want a microcontroller with at least 10 I/O lines, if I'm counting right. The program should be pretty small, and doesn't need much read-write memory. You'll want some small amount of non-volatile memory to store the passcode, though I guess with more I/O lines you could make it switch settable.

Is that enough information? Do you need more details for any specific part?
 
I'd like to stay away from programming and little gadgets and circuitry like those as i'm not very "smart" in that area.
 
Then how do you expect to implement this?

Is it that you're looking for a solution ready-made? I can't say I know of anything. Even if there was something, wouldn't you have to modify it at least slightly to do what you want?

The lock you're describing is used in safes at hotels and even in building applications. In that case, it pushes or pulls a plunger, and you'd have to find a way to make that a momentary contact instead of a stable push-pull.
 
skandaluz said:
I'd like to stay away from programming and little gadgets and circuitry like those as i'm not very "smart" in that area.
Click to expand...
Oh come now. That's the whole reason anyone does projects around here. To learn something. :p Seriously, though, it's not all that complicated, and you'll have a lot of fun doing it.
 
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