this instructable is on making a very easy and useful momentary switch, a biased or "push-to-make" switch that is only activated when pressed. also, at the end there is an easy to make example of what could be done with this type of switch--a floor tile to house the switch and a diamond pleated folded paper form that is lit with a simple LED circuit, triggered by the switch.
Step 1: What You'll Need:
[for the switch]
• a 1' square piece of 1/2" carpet padding (or any other comparable foam sheet)
• (2) 1' square pieces of aluminum window screen
• electrical wire, 20 gauge or so. I used intercom wire for this project, which has two strands in one to keep it neat. you can also use speaker wire if your project is low voltage (battery powered, NOT plugged into the wall)
• an LED (brightness/size up to you, but make sure and use the appropriate resistor to keep from burning out your LED)
• a resistor
• electrical tape
• duct tape
• 9V battery
• an 8.5" X 11" piece of vellum paper
• an adhesive faux stone floor tile, available at most big box hardware stores for $1
• PCB board or bread board if you want to do something complex
Step 2: Prepare the Aluminum Screen Material
trim a 1" border off of each piece of aluminum screen material. you want it to be a bit smaller than the carpet padding.
Step 3: Cut the Foam
fold carpet padding swatch in half, cut out a circular piece that is approximately 7-8 inches in diameter
Step 4: The Circular Hole
Step 5: Cut a Small Square of the Foam From the Scrap
from the circular piece of padding that's left over, cut a small square (about 1" in diameter). this piece of padding is crucial to the proper functioning of the switch--it keeps the switch in the "up" position when not being pressed.
Step 6: Attach the First Screen
using duct tape, secure one of the aluminum screen pieces to one side of the foam
Step 7: Secure the Square in the Middle
turn the switch over. using a small piece of duct tape, secure the padding square to the center of the piece of screen material that you just attached to the foam in the last step.
Step 8: Attach the Second Screen
attach the second piece of screen material to the switch. you should now have screen on either side with the foam square in the middle.
Step 9: Prep Wire for the First Screen
strip about 1/2" off of one wire, bend the end to make loop.
Step 11: Attach the First Wire
hook the wire securely under one piece of the screen, the one that is facing up. it is really important that you place the wire in one of the corner with padding underneath--it will be easier to secure and will not accidentally get caught in the other side, causing the switch to stay on.
Step 12: Tape Down the Connected Wire
secure the wire to the switch by placing a piece of duct tape over it, being careful not to tape in the circle of exposed screen.
Step 13: Attach the Second Wire
turn the switch over and repeat steps 9-12 to attach the second wire.
Step 14: Finished Switch/put the Switch in Something
now the switch is done. when the switch is pressed, the screens touch and completes the circuit. connect it to your project (see step 15).
at this point, the switch can be used in a variety of ways. for example, you can put it in a freezer bag, inside a cushion or pillow, or attach it to a floor tile.
Step 15: Simple Example of Use: Turn an LED on and Off
wire it between your power supply and what you'll be switching on and off. for example, I wired it between the positive side of a 9V and the resistor (I used a 1K) that is attached to the anode (+, long) side of the LED. The cathode (-, short) was wired separately to the negative side of the 9V.
Step 16: One Option for Housing the Switch
by securing the switch to the bottom of a thin faux stone floor tile, you can make the switch more secure and use it for project where a floor switch is most appropriate. you could make the switch flush with the floor and hide the switch, if that's the effect you're after.
to do this, simply secure the switch to the bottom of the tile with duct tape.
Step 17: Finished Floor Tile Switch
Step 18: Example of Using the Switch: Light a Diamond Pleated Folded Paper Form
in this example, the LED/9V circuit is attached to the wall behind a diamond pleated folded paper form. the viewer (in this case, artist Brittany Ransom) is simply stepping on the floor tile switch to activate the LED.
Step 19: Make the Paper Form
use the template linked from step 20 to fold the form from a 8.5" X 11" piece of paper. paper vellum is the best choice if you're using paper, but this form can be folded from a variety of thin plastics. print out the template on the paper vellum, and then fold. the red lines are for valley folds and the blue lines are for mountain folds. more on that here: http://en.wikipedia.org/wiki/Origami_techniques
after you make the folds, you will need to press the valley folds in and the mountain folds out. this can take a bit of time. as you do, the form with try to curve. this is normal. to make the form in this image, simply let the form curve and then connect the two ends together as they join in the back.
Step 20: Template Pdf
you can download the pdf of the template here: