Chibitronics Pressure Sensor
30-60 min
Ages 8+
What Will You Make?
Students will use a special pressure-sensitive conductive plastic that becomes more conductive when pressed to create a pressure sensor that can fade an LED both in and out.
What Will You Learn?
You will learn to use a pressure sensor circuit to fade an LED in and out, use a pressure sensor to light colors in sequence and explore other pressure sensor effects, and use interactivity to tell a story.
Start with the Template
Step 1
Stick conductive tape over the gray lines.
Step 2
Fold the top page corner along dotted line and clip your battery in place with a binder clip.
Step 3
Stick an LED sticker over the footprint and fold along the dotted line at the bottom of the page. Your LED will turn on, since you’ve just made a switch!
Step 4
Unfold the switch you just made and cut the black conductive plastic in the shape of the red dotted rectangle.
Step 5
Put the plastic over the dotted rectangle and fold the bottom flap again. Now when you press, the light will become brighter the harder you press – you just made a pressure sensor!
Start with Art
Step 1
Ask students to brainstorm: what different stories could this circuit tell? What kind of meaning will their pressure-sensitive circuit communicate? Building on the initial group brainstorm, ask students to sketch ideas before creating the illustration to go with their circuit.
Step 2
Share the heart card video of an interactive greeting card made using two LEDs and a pressure sensor made from Velostat as an example.
Troubleshooting Tips
Check for breaks or tears in the conductive tape path and patch them if needed.
Make sure the positive side of the battery is connected to the positive side of the LED, and the negative side of the battery is connected to the negative side of the LED. Students can experiment by turning the battery over.
Check for short circuits – places where the positive side of the circuit makes an accidental connection to the negative side of the circuit.
Make sure the LED is solidly connected to the conductive tape path. Press down on the LED to test if the connection is secure.
Make sure the battery is not out of charge by testing it on a working circuit. If a student has tried all other strategies, give them a fresh battery to try.
Other valuable troubleshooting strategies that students can suggest include:
asking a classmate for help
looking over the instructions again
comparing their circuit to a working circuit
changing one element at a time
What Is Happening Here?
Background
Pressure-sensitive conductive plastic, sold by the brand names Velostat or Linqstat, is a thin plastic containing conductive carbon particles. This gives it an electrical resistance that changes with pressure. In other words, how well it conducts electricity changes when you press on it. We can use this to make a pressure sensor.
When you are not pressing on the plastic, the conductive particles in the material are spaced farther apart. Electrons cannot flow as well, so the light is dimmer. The harder you press, the closer the conductive particles become and the better the material conducts, so the light shines brighter.Â
What Is Next?
Extensions and Adaptations
Try sandwiching a piece of the pressure sensitive conductive plastic between the battery and battery flap in any of the circuits students have built so far to see the blink effect become a gradual fade! The same trick works for gaps in switch circuits, creating a more gentle effect. Try moving the conductive plastic piece around different existing circuits. But watch out for short circuits: make sure the conductive plastic does not bridge the + and – of the circuit.
Use the pressure sensor circuit to explore the electrical properties of other materials, as in the Circuit Science: Conductors, Resistors, and Insulators activity that follows.
Build on pressure sensor effects using the ideas in 6 ways to use a pressure sensor. Students can work in groups to plan out how to explore one of the techniques, and then request the materials needed for their project.
Chibitronics Educators Guide
Chibitronics Paper Circuits STEAM Educator’s Guide is a FREE comprehensive guide to STEAM (Science Technology Engineering Art and Math) learning with paper circuits!
This 185-page guide includes:
Overview and history of paper circuits, including materials, techniques and troubleshooting tips
Suggested learning standards
Resources on equitable teaching and collaboration in the classroom
7 detailed lesson sequences based on the Circuit Sticker Sketchbook in Part 1 Lessons
12 detailed lesson sequences based on Love to Code in Part 2 Lessons
6 Featured Projects: cross-curricular adaptable project inspirations
Printable templates for each lesson sequence
Throughout the guide, Chibitronics celebrates artists, educators, art techniques, and projects to showcase inspiring work in action. The arts are interwoven into each activity; STEM becomes a medium to ask and explore big questions about ourselves and the world, and nurture new forms of creativity!
Materials:
- 1 Circuit Sticker LED in any color
- 13 inches conductive tape
- 1 CR2032 battery
- 1 small binder clip
- Small strip of pressure-sensitive conductive plastic
- Pressure sensor template
