Intro:
As I was punching a keypad at work I started thinking, “Man I
wish I was at home on the couch…” Enough about that though. :) I was also
thinking it would be cool to use a keypad to power on my computer. I remembered
seeing keypads that installed on home doors, so I started to research that. I
then went to electric gate keypads. All of these options were just plain too
expensive! I then stumbled on garage door opener keypads… PERFECT!
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| (1)
What you get |
(2)
Simple enough…right? |
(3)
Keypad connects with an phone jack |
Do it to it:
These retail for about $30-40, so I felt like that was still
too pricey. A quick eBay search revealed them selling for $17 w/$7 shipping and
handling. So after it was all said and done I paid $24. The one I acquired is
the Domino Garage Door Keypad. It has a keypad unit that is connected via wire
to another module that replaces the garage door button. This unit is really a
glorified relay, so all I have to do is wire it into the power button. This unit
uses a 1 to 6 digit code, that when entered incorrectly 5 times will lock the keypad
for one minute. When a button is pressed the keys are backlit green, schweet.
The projected battery life on this unit is 3-5 years, so I don’t think that will
be a problem!
This unit consists of the external keypad and an internal
module that houses the codes and the relay. There are a couple of ways you can
hook this up, the Windows way and the Linux way. The Linux way hooks the switch
leads up directly to the control module and the Windows way uses a single pole
double throw relay to switch from the module to the power button. On occasion I
am forced to hold down the power button for the prescribed five seconds to kill
my windows machine. It goes without saying that a Linux machines don’t have this
shortcoming.
Taking a good look at the back of the keypad reveals a few
details. One is that we have to drill a hole in the case to run the wire through
and two is that the screw holders on the keypad are not flush on the back. Just
take you favorite implement of destruction and excise them. Ain’t that perdy? I
then took my drill, and did what drills do best.
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| (4) Tape it |
(5) Drill it |
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| (6) Marvel at it |
(7)
Attach the keypad |
Now it is time to decide where to place the internal module.
I chose under my HD’s in the front of the case. I ran the cable from the keypad
down the case and plugged it into the module. Then, using double-sided tape,
stick the module in place. If you are doing the Linux version, simply cut the
wires going to your power switch and hook them up to the internal module. Linux
users are done! Windows users, read on.
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| (8)
Make it prettyful |
(11)
Module attached |
For all of you electrically inclined, I included this
diagram. For the rest of you…good luck! Hehehe…just kidding. The idea here is to
wire both the keypad and the power switch to power up the computer. The power
switch should be disabled while the power is off so that you can only use the
keypad. The opposite should also be true. My solution was to use a double pole
single throw relay. What does that mean?
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| (9)
Windows wiring diagram |
(10)
Black square is the relay |
Imagine a relay in your head as a v shape. The top two points
on the V are labeled point A and point B. The bottom point on the V is point C.
You wire into point C with your positive lead. When power to the relay is off
then point C is connected to point A. When you supply power to the relay, point
C is connected to point B. When electricity is applied to the relay it creates
an electro magnet that switches and internal switch between 2 points. Soooo, the
relay is really a fancy switch. Only instead of switching it with your hand you
use electricity!
So here’s the low down. One wire coming from both the
internal module and the power switch are wired together and intern wired to one
of the wires coming from the MOBO pins. The other wire goes to our relay. Then
the internal module is hooked up the pin on the relay that is normally closed.
Then we hook our power switch wire up to the remaining relay pin (normally
open). Then all one has to do is tap into your PSU’s 12volt rail. I used an
inline connecter off of a dead fan to accomplish this. Now to program a code.
Programming of the keypad is simple. Slide the button to
program on the internal module. Hit enter, your password, and then enter. Slide
the button back to operation and you are good to go.
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| (12) Closed |
(13) Opened |
(14) Looks like a keypad to me |
The Movie:
Below you can find a movie of the keypad in action. It is in
Windows Media Format, about 22 seconds long, and 760kb or so
zipped up.
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| (15) Moving picture show. |
Closing:
The whole process only took about 30 minutes and was pretty
fun. This would be a pretty popular LAN party mod as well as one for anyone who
is security minded (to a bizarre degree). :) If you guys have any questions or
comments, take it to the Forum, or contact
me. Thanks for reading and I hope you enjoyed this.
