How to build a DIY rat trap out of cardboard

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Do you have a rat problem but don't want to harm the little creatures? Then make your own humane trap from cardboard.

As you can imagine, you'll need some tools and materials before you get started.

Materials and gear needed

• Cardboard
• Metal ruler
• Crafting knife
• Wooden skewers
• Sticky back plastic
• Hot glue gun
• Rubber band
• Switch
• String
• Popsicle stick
• Motor
• Electrical wires, resistors, and soldering gear

With all your gear in hand, let's get on with the build.

Step 1: Make the base

The first step is to take your cardboard and draw a line diagonally from one corner through to the center. With that done, mark out a point 1.5 cm to one side of the line and draw another line parallel to the first. 

Next, sketch out a right-angled triangle using the second line as its hypotenuse. 

Next, take your crafting knife and cut out the triangle you've sketched on the cardboard sheet. To make this process easier, use a long metal ruler to guide you.

With that done, take your wooden skewers and pierce them through the cardboard triangle to make a kind of cage. Once done, snip off the excess lengths of skewers as needed. 

Rinse and repeat to make a second triangular cage wall. With that done, sketch out two large rectangles and also insert a series of skewers to make two more walls of the cage. With that done, sketch and cut out two squares and two triangles of cardboard.

Step 2: Assemble the cage

Using some sticky-backed plastic, stick the two squares of cardboard together to make the floor of the cage. With that done, take your hot glue gun and apply a line of it to the bottom edge of each of the triangles of cardboard.

Glue the base of the cage along both edges of the triangles as shown below. 

With that done, use some more hot glue to affix the rectangle barred walls to either side of the cage along the next longest edge of the triangles.

Finally, glue the triangle-shaped barred cage walls opposite the solid triangle shapes as shown below. 

With that done, you should now be able to fold the cage closed on itself along the taped base. 

Step 3: Make the trigger mechanism

Next, sketch out and cut out a basic trigger plate for the trap. Using your hot glue gun, stick a length of a plastic lollipop stick one end of the trigger. With that done, glue a bent length of metal to the bottom of the trap trigger as shown below. 

With that done, glue a length of wire to the metal hook and affix it to the side of the trap trigger. Next, make a second cardboard trigger piece, and add another hook of metal and length of wire as before. 

With that done, attach the two pieces together with an elastic band, with the wires in between the cardboard sandwich. This will now act as a basic pressure plate.

Next, take your popsicle stick, motor, and a pair of metal washers. Cut a short length of the stick and glue it between the two washers. Then attached the washers to the rotor of the motor.

With that done, wire up the wires from the pressure plate to your switch, the motor, and a battery. When the pressure plate is depressed, the rotor of the motor should spin freely.

With that done, make a basic cardboard trough and glue it to one edge of the main cage. This will house the motor. 

Step 4: Complete the trap

Next, take the pressure plate and place it inside the cardboard trough. Place the pressure plate between the "jaws" of the main cage. With that done, cut a piece of string and attach it to the rotor of the motor. 

Next, glue the other end of the string to the other "jaw" of the cage. 

Finally, close up the trough with another strip of cardboard. With that, your DIY humane rat trap is now complete.

Now all you need to do is bait the trap and wait for an unlucky rodent to find the trap! When it triggers the pressure plate, the motor will trigger and close the cage automatically. 

If you enjoyed this build, you might enjoy making another rat trap?