Is your little sister sneaking into your room when you're not there? Set this little trap to tell if anyone has been through your door.

This project was created for YuKonstruct's first Build Night in collaboration with hacker-cycle and licheness.

YuKonstruct is the first makerspace in Canada's north. Our mission is to provide access to shared space, quality tools, available expertise, and a collaborative environment to help makers build anything!

Step 1: Gather Your Materials

You'll need:

clothes peg
adhesive copper tape (conductive)
glue gun and glue sticks
LED
Coin battery
Plastic, cardboard or other non conductive material (we used a business card)
string, twine or fishing line
scissors
hole punch
pliers
drill and small drill bit

Step 2: Drill a Hole in the Clothes Peg

Drill a hole in the end of the clothes peg.

Step 3: Take the Clothes Peg Apart

Take the clothes peg apart.

Step 4: Cut the Copper Foil

Cut the copper foil into one square and a long piece.

Cut the long piece in half lengthwise and the square in half.

Cut one of the halves of the squares in half lengthwise.

Step 5: Add the Copper to the Clothes Peg

Take a long piece of copper foil and stick it to the first half peg (side A). Begin on the inside of jaw, go around the nose and line inside the groove where the wire goes.

Take other long piece of copper, cut a 3⁄4” piece off the length and set it aside. Stick the rest to the other half peg (side B). Again, begin inside the jaw go around nose and down the back. The 3/4" piece of foil is used to line the groove with the rest laying towards the end of the peg. There will be a gap between the two pieces of foil on this side.

Put the clothes peg back together.

Step 6: Attach the Battery

Stick half of the next longest copper to the negative side of battery with excess hanging over the edge.

Place positive side of battery face down over groove (side B) and line up the overhanging foil edge with foil running towards back of the pin.

Stick foil to foil. Fold the battery back, turning positive side up.

Hot glue the negative side of the battery to the wood.

Step 7: Add the LED

Flatten LED leads out to sides in opposite directions. Place positive lead (the longer one) on positive side of battery and negative lead on foil going around the nose of the clothes peg (side B) (use pliers to shorten leads by curling ends). The light should come on.

Stick the leads securely in place with the remaining pieces of foil.

Step 8: Final Details

To turn the LED off, place non-conductive material (like a business card) between jaws of the clothespin to break the circuit.

Punch a hole in the card and attach half of the string. Attach the other half to the hole in the clothespin.

Step 9: Setting the Trap and Other Uses

Tie the two ends of the string to different objects (like a door handle and a bedpost). If one is moved, the card should pull out and the LED will light up.

You can also use this device to test whether a material is conductive or not. Pinch the material between the clothes peg's jaws; if the light comes on, the material is conductive.