When I was a kid my father had a panic button under his desk that was wired to call 911. While I thought this was pretty cool at the time, it later occurred to me that he had this because the neighborhood that his business was located in was a bit rough, and -- perhaps -- we were in perpetual danger. Nonetheless, I always thought the idea of having a panic button was pretty darn neat. Perhaps this notion stuck with me for so long of a time because I was never allowed to press it as a kid. It was 'off limits,' and thus a very appealing idea.
Now that I am an adult and have a desk of my own, I resolved that I too needed a panic button. However, I feel like one that calls 911 has limited use in my line of work, and my opportunity for panic was probably less severe. So, I decided that I needed to tone it down a bit. The under desk panic button that I have created dials my own phone when it's pressed.
Of course, you may be wondering why on Earth I would want to call my own phone. Think of this way -- an annoying coworker walks over to your desk with the intention of locking you into a long dull impromptu meeting. You have nowhere to run; nowhere to hide. There is only one way to get out of this -- you need something more important to do. Perhaps now you can see how a device that places a call to yourself may come in extremely useful. If you still can't see it, picture this; Your phone rings. You explain that you need to take this important call. In fact, this is going to take a while. You will need to continue this conversation later. Crisis averted thanks to the Desk Panic Button.
Step 1: Go Get Stuff
(x1) Arduino Uno (Radioshack #276-128)
(x1) GPRS shield (Radioshack #276-246)
(x1) SIM card (Radioshack #17-8167)
(x1) CR1220 coin battery (Radioshack #23-793)
(x1) Momentary button switch (Radioshack #275-646)
(x2) 1/8" mono jacks (Radioshack #274-251)
(x1) 1/8" male to male mono cable (Radioshack #42-2420)
(x1) M-type power jack (Radioshack #274-1582)
(x1) M-type power plug (Radioshack #274-1569)
(x1) 1" x 2" x 3" project enclosure (Radioshack #270-1801)
(x1) 2" x 2.5" x 5" project enclosure (Radioshack #270-1803)
(x1) 9V power supply (Radioshack #273-355)
(x1) 6" x 6" x 1/8" acrylic sheet
(x1) 1" x 4-40 nut and bolt
(x2) 1" x 6-32 wood screw
Step 2: Prep the Shield
Step 4: Drill
Drilll a 1/2" hole centered on the other 1" x 2" side.
Step 5: Pushbutton
Step 7: Drill
On the opposite side of the project box, drill a 1/4" hole on the center face for the 1/8" jack.
Drill another 1/4" hole right around the corner on the 5" x 2" face of the enclosure for the power jack.
Step 8: Attach
Insert the M-type power jack into the other 1/4" hole and fasten it in place with a mounting nut.
Step 9: Solder
Solder a black wire from the other solder lug of the pushbutton switch to the ground terminal on the 1/8" jack.
Step 10: Connect Wires
Solder a 6" black wire to the ground terminal on the 1/8" jack.
Solder a 10K resistor and a 6" red wire to the signal terminal on the 1/8" jack.
Finally, solder a 6" green wire to the other side of the 10K resistor.
Step 11: Power Plug
Solder the red wire to the plug's tip terminal, and the black wire to the plug's barrel terminal.
Screw the casing back onto the plug.
Step 13: Wire It Up
Connect the green wire wire to the 5V socket on the GPRS shield.
Connect the black wire to the ground socket on the GPRS shield.
Connect the red wire to pin 2on the GPRS shield.
Step 14: Attach the Antenna
Step 16: Cut
The solid black area around the center hole should be etched down 1/16".
Step 18: Attach
Drill these marks using a 3/32" drill bit.
Place the 4-40 nut into the etched portion of the center hole and then firmly mount the acrylic bracket to the desk with 6-32 wood screws.
Step 19: Mount
Fasten it in place with 1" bolt.
Step 20: Power
The whole system should now be active.
Step 21: Use
Discretely press the button, and politely excuse yourself when the phone rings.