E-Textile Pressure Sensor
Pressure sensor is a type of analog sensors that produces continuous signals. It senses the amount of pressure, and convert it into digital signal.
If you are using piezo-resistive material, e.g. anti-static foam. The current comes from one layer of conductive material, and goes across the piezo-resistive materials to the other layer of the conductive materials. When being pressed, the conductors in the piezo-resistive material are squeezed tighter, allowing current to pass through easier. This results in an expression of sensitivity to pressure, the resistivity decreases and conductivity increases as pressure is applied.
Tutorial by Mei Zhang, Queen Mary University of London
If you are using resistive material, e.g. Velostat. The area of contact between conductive layers and resistive material increases under pressure. A better contact reduces resistance, and allows current to pass through easier.
This tutorial guides you to create a simple e-textile pressure sensor. Click here to see more examples following the same principle.
Watch the tutorial
------------content of this video-----------
00:00 - intro
01:23 - prepare materials
02:22 - making with template
03:49 - testing
Read the tutorial
Materials
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Anti-static foam (or other (piezo)resistive material, velostat would work great)
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Copper coated fabric (or any other conductive material)
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Iron-on adhesive
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Non-conductive fabric
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Non-conductive thread
If using template, find out the elements in below picture
Tools
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Iron
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Needle (or sewing machine)
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Scissor
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Baking paper
Making steps
Skip to step 4. if using the template.
1. Iron the adhesive to the back of the copper fabric
2. Cut the copper fabric into two squares each with an extended leg, and cut two pieces of the non-conductive fabric to be the substrates
3. Cut a square of anti-static foam that is larger than the square of the conductive fabric
4. Iron to fuse the copper fabric on the non-conductive fabric
5. Sandwich the anti-static foam in between the copper fabric.
Make sure the foam has fully spaced the two conductive layers apart to avoid short circuit
6. Secure the circuit by sewing the edge of the non-conductive fabric.
Double check to make sure there is no chance for the two layers of conductive fabric to contact with each other! Otherwise your sensor has a risk of short circuiting!
7. Your pressure sensor is done!
8. To test the sensor, set the multimeter to a proper resistance measurement setting, you should see the ohm reading changes when pressing the sensor.
