DIY: Pressure Sensitive Mats

You can make a simple pressure sensitive mat in your home.

You can find pressure sensitive mats in everything from high-tech security systems to grocery store doors. The concept is basic: two wires are held apart until external pressure pushes them together, activating whatever is connected. You can make a simple pressure sensitive mat with items from your local craft or electronics stores. You can use it for a simple burglar alarm or to activate an effect at Halloween.

Things You'll Need

• Plastic sheeting
• Scissors
• ¼-inch upholstery foam
• Craft foam
• Marker
• Copper discs (12)
• Hot glue gun
• Wire
• Wire cutters/strippers
• Soldering iron
• Rosin core solder
• Sponge
• Rubber cement
• Duct tape

Instructions

1. Cut two 18-inch by 30-inch rectangles out of thick plastic sheeting with a pair of scissors. Cut an identical rectangle out of ¼-inch upholstery foam, and two more out of thin pieces of craft foam.

2. Cut six 1-inch holes in the upholstery foam rectangle, arranged in two rows of three. Evenly space them over the entire surface.

3. Set the upholstery foam on each plastic rectangle and trace the holes' location with a marker.

4. Glue a 1-inch copper disc to each marked circle on the first mat using hot glue.

5. Cut six 12-inch pieces of insulated wire with wire cutters.

6. Strip ½-inch of insulation off both ends of the wire with wire strippers.

7. Plug in a soldering iron and let it heat up.

8. Hold the tip of the soldering gun against a piece of rosin core solder. Completely coat the tip of the gun in solder, then immediately wipe off on a wet sponge. This is called tinning, and helps the solder flow smoothly.

9. Hold the end of a wire to the first copper disc, and hold the end of the solder against it. Touch the iron's tip to the solder, melting it and covering the wire. Allow the solder to cool, fusing the wire to the copper disc.

10. Repeat this process for the other five discs.

11. Poke the wires through the plastic sheet so they extend out the back.

12. Twist the loose ends of the wires together with the stripped end of an additional 3-foot wire.

13. Repeat Steps 4 through 10 on the second plastic mat.

14. Glue the plastic mats to the upholstery foam with rubber cement, with the discs lining up with the foam's holes.

15. Cover the top and bottom of the mat with the two craft foam rectangles, held in place with duct tape. The 3-foot wires should extend at the same place.

16. Wrap the entire mat lightly in duct tape. Do not wrap the tape so tightly that you force the discs together.

Tips & Warnings

• You can hook up the wires up to a battery and buzzer or any other device. When you step on the mat, it compresses, allowing the discs to touch. This closes the electrical circuit, activating the buzzer.

References

• Aaron Cake: How to Solder