With eight rat traps and a handful of LEDs, you too can make a loud noise that looks interesting with your very own glowing mousetrap machine.
Step 1: Materials
The most important part of the project is getting the right mousetraps. Don't be tempted into buying the little ones with the plastic cheese triggers - go to Home Depot and invest in the large Victor brand rat traps. While you're there, get yourself some wood screws and a circular mounting board (13 inches diameter).
Next, you'll need some 5 mm red LEDs. I got mine from circuit specialists in Mesa, AZ - $1.64 for a bag of 100. Don't get them at radio shack. You'll need at least 24. Any number divisible by eight should be fine.
Also get some hook-up wire, alligator clips, and a potentiometer.
For tools, you'll need an electric drill or a screwdriver and lots of patience.
Step 2: Schematics
As you can tell from the detailed drawings below, each trap has three LEDs imbedded in it, wired in series. From here each trap is wired in parallel from the screws in the center of the board (there are two sets of two screws, positive and negative, both wired to the power source - 6V 300 mA DC).
This means that the traps can light up independently of one another. Each trap acts as a switch for its own lights with wires leading from the metal "bow"(ie the thing that is supposed to hit the mouse) and the trigger bar (the thing that keeps the bow from going until the trigger is moved). Refer to the second picture for more detail. The circuit is closed when the trap is set, so the red LEDs sort of act as "warning" lights. The schematic shows how two of the traps would be wired. The other six would be done in exactly the same way but are omitted in the picture for clarity.
I put a potentiometer at the beginning of the circuit so I could control the brightness of the LEDs simultaneously. It's not necessary, though, since the current and voltage going through the 24 LEDs is pretty well suited to the task.
Step 3: Putting It All Together
Now that the theory is out of the way, it is time to construct the thing.
Screw three holes in each trap and insert the LEDs into them. Twist their ends together, being sure to attach positive ends to negative ends as you link them. Tape them in place.
Divide the circumference of the circle backboard into 8 equal parts and lay out the traps in a fairly even manner (easier said than done). Screw the traps into the board, as in the picture. Also put four screws in the center as electrodes.
Now wire it together. The messier the better, for that crazy homemade look. I used alligator clips to attach the initial leads from the wall wart. Use a staple gun to staple all the wires in place.
Plug it in without electrocuting yourself (important) or just use a battery if you're a coward. The LEDs should light up when you set the traps and stay lit until you set them off. If not, you must debug the system.
Step 4: Activation!
Set the traps, turn off the lights. Admire how cool it looks and how purposeless and dangerous-looking it is. Literalists or people with dark senses of humor may want to invest in a toy mouse to set it off with. Don't let real animals set if off, please.
If all goes well, the first trap being set off will create a chain reaction causing them all to go off near-simultaneously. It will be loud and the LEDs will go out - all to very dramatic effect.
Arm the traps and leave them on in a common area of the house. Allow people to sit and contemplate all the potential energy and the fragility of the system. After doing this long enough, it will probably seem like a metaphor for something.