Submitted by Montana Ethical Hackers for the Instructables Sponsorship Program!
Step 1: First Get All Your Materials... Including a Doomed USB Keyboard.
1) phillips screwdriver
1) usb keyboard with quick keys/shortcut keys(will be destroyed). You want a keyboard that has "special" buttons like in the top of the picture. You can use a wireless keyboard for a wireless but short range setup!
2) two thin wires (24-26). This is the stuff in phone line wires or cat 5 network cable. You want a single solid thick wire inside.
3) A mailbox
4) Chip Clip or Binder Clip (will be destroyed)
5) A couple of wooden shims or pieces of wood (will be destroyed)
6) 2 wood screws (1”1/4)
7) thin piece of tin or a workable metal. 5-8" long. 1-5" wide. Less than 1/8th inch thick. You'll want two of these if your mailbox is not made of metal.
7) wood glue (or a couple more 1”1/4 wood screws)
8) Computer with XP or above(yes, that includes Linux)
Step 2: Take Apart the Keyboard
Step 3: Ignore the Keyboard GIBLETS!
Step 4: Comprehend How a Keyboard Works
Step 5: Remove the BRAIN!
Step 6: Tracing the Circuit Like a Boss
1) Literally trace the line with a marker or highlighter
2) Use a continuity tester on a multimeter(or similar device)
3) Build our own continuity tester with two wires. This is what I did. I found it faster than highlighting, but that could be due to dyslexia.
MARKER or HIGHLIGHTER method:
You can bust out a marker and draw lines all the way back from the "Mail" button to the circuit board. That's really hard though and I'm dyslexic. Draw a line from the circle that represents the "Mail" button all the way to the circuit board. Try using a sheet of white paper to prevent you from getting lost. Do this for both clear circuit sheets
You can also use a multimeter, but most people don't own one(though I do). Unplug your keyboard if you do this! Simply flip your multimeter to the continuity setting. Put one probe(it doesn't matter which one) on the dot for the "Mail" button. Run the other probe across the connections to the circuit board. When the multimeter moves or changes you have the right connection. Highlight the connector that makes the multimeter move. Do this for both clear circuit sheets
The SUPER AWESOME MAKE-YOUR-OWN CONTINUITY TESTER:
So plug in your USB keyboard.. and grab your two 24-26 gauge wires. Don't worry, this wont hurt; the voltage is NOT enough to hurt(let alone kill) you. It could damage your keyboard so only tap the wires to test them. Never leave the wires connected to each other!
Strip about 1/4 inch off of all ends of the two wires. If you're using networking cable(not telephone cable) you can strip the wire with your thumbnail.
Now you should find a little white connector plug near the lights. If you don't have a plug, you can hold the two wires to the two metal dots on the bottom of any LED. If you have a plug, push the one of your wires in from the other end of the red wire and the other one of your wires into a different hole. Connect the two wires. Did any of the lights go out or change in brightness? If not, keep trying different holes with your wires. If none of those work, try switching to a wire other than red. If that still doesn't work, your wires or keyboard may not be plugged in. Once connecting your two wires makes a change, continue on. You've just made a continuity detector from your keyboard! Maybe I'll make an Instructable on that
Press one wire to the mail dot on a clear circuit board. Run the other wire across the pins at the bottom. When the keyboard lights change, you have found the right connector. Mark that connector with a marker!
Good job! You've just traced a very simple circuit! Do this for both clear circuit sheets
Step 7: Transfer Your Trace to the Circuit Board
Step 8: Put Your Two Wires Where You Highlighted/marked Your "Mail" Button Connections
Put both of the wires exactly where you place your markings. Then screw down the metal plate that held the clear plastic circuit sheet to the circuit board.
Plug your computer in and make sure that the computer thinks you hit the "Mail" button when the two wires touch.
Step 10: Download My Code and Run It.
You may need to download the .NET 4 framework first before running it.
1) Connect the two wires you've inserted into your disassembled keyboard circuit.
2) Note the "Recognized Number:" at the top.
3) Disconnect the two wires.
4) Put that number into the top text box
5) Enter your gmail username into the second text box. Create a gmail account if you don't have one.
6) Enter your GMail password into the third text box.
7) Click go.
8) Connect the two wires then disconnect them again. Go to gmail.com to oserve your new email sent from yourself!
Step 11: Build a Trigger Mechanism for Your Mailbox
Grab your chip clip. We're going to make it look like the first image.(Picture #1)
Drill a hole in only one half of the chip clip or simply snap off the top half of one side of the chip clip. Then put one of your wood screws through the other half(Picture #2)
Now put a piece of metal on the side of your chip clip that does not have a nail drilled through it. Picture #3 gives you an idea of what we kinda want to end up with. I also made a nice animated diagram in the next step if you're not sure how this all goes together. You will likely have to bend/break the other side of the clip(Picture #4). This clip should open and close freely with the metal attachment.
Take your two shims or blocks of wood(Picture #5). Screw them onto the clip so that you end up with an elevated trigger(Picture #1 again).
Step 12: Mount Your Trigger
Clean the surface you will be gluing on the mailbox. Also clean the surface you will be gluing on your trigger mechanism.
Place down a continuous thin layer of wood glue(Pic #1). You could also use wood screws or bolts to mount your trigger.
Clamp your trigger to the location you have added glue(Pic #2).
Now attach the other ends of your wires to the metal. I just crimped mine into the metal plates with a pair of pliers.
If you have a wooden or plastic mailbox(like my example), you will want to put a second sheet of metal to create a contact(see animation). I if you have a metal mailbox, just wrap the second wire around any metal bolt/screw which connects to the metal mailbox.
I made a simplified animated diagram to further help you understand the concept: