Build a science fair lie detector lesson plan
Skin response and heart rate against a calm baseline: a science demo of the stress response, not a real lie detector.
Objectives and materials
By the end, students can
- Read skin conductance in real units, then measure it against a calm baseline.
- Add a heart rate sensor and turn both changes into one stress bar.
Materials for the whole unit
- Arduino Uno R3
- Full-size breadboard
- Galvanic skin response sensor
- LED bar graph, 10 segments
- MAX30102 pulse oximeter
- Pushbutton
- Resistor x 10
Every part is already on the simulator’s bench, so there is nothing to buy or hand out. The counts are the most any one lesson uses, if you build it on real breadboards too.
The skin
Read skin conductance in real units, then measure it against a calm baseline.
| Lesson | Time | What students do |
|---|---|---|
| Read the skinA galvanic skin response sensor and a ten-segment bar graph. How skin conducts, how a formula turns a reading into microsiemens, and why sweatier reads lower. | 40 min |
|
| A calm baselineMeasure ten calm seconds first, then show only the change from them. Why a change from someone's own baseline means more than any single number. | 40 min |
|
Materials
- Arduino Uno R3
- Full-size breadboard
- Galvanic skin response sensor
- LED bar graph, 10 segments
- Pushbutton
- Resistor x 10
Check for understanding
Each student finishes "A calm baseline" on their own, without opening the hints. The simulator checks 4 of its 4 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Back to calm".
The heart
Add a heart rate sensor and turn both changes into one stress bar.
| Lesson | Time | What students do |
|---|---|---|
| Add a heartbeatFinish the science fair build: a MAX30102 heart rate sensor joins the skin sensor, and both changes from the baseline fill the stress bar. | 40 min |
|
Materials
- Arduino Uno R3
- Full-size breadboard
- Galvanic skin response sensor
- LED bar graph, 10 segments
- MAX30102 pulse oximeter
- Pushbutton
- Resistor x 10
Check for understanding
Each student finishes "Add a heartbeat" on their own, without opening the hints. The simulator checks 4 of its 4 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Finger off".
Teach this unit as a class
Start a class from this course and its 3 lessons are assigned in one go, in order. Students join with a six-character code or printed login cards, and each one’s work comes back to you.
The class tools are free for 30 days for one class of up to 20 students, with no card. The lessons themselves are free either way.