PulseSensor Science Fair Projects

Lane 3 · Science at home

Pick one question. Run a fair test.

Start with a clean pulse waveform, change one thing, repeat the trial, and explain what the evidence supports—and what it does not.

Start the beginner project Plan your experiment

Before you begin

Prepare and insulate your PulseSensor before skin contact. Use gentle pressure and stop if anything feels uncomfortable.

What you need

A PulseSensor kit, a compatible board with an analog input, USB cable, and either the WebSerial tool or Arduino with PulseSensor Playground.

Three complete starter projects

Begin with a result you can explain.

Run at least three trials per condition. Save the raw waveform—not only BPM or a screenshot—and label every trial.

Beginner1 sensor30–60 minutes

1. Make a clean PPG graph

Question: Which features repeat from beat to beat in a quiet optical pulse waveform?

ChangeNothing yet. This is your baseline and repeatability check.

Keep constantBody site, posture, attachment, pressure, light, sample rate, and trial length.

RecordThree 30-second raw trials. Mark peaks, baseline drift, and rejected sections.

GraphPlot raw amplitude against time and label one usable and one rejected section.

You’ll finish with: one labeled raw waveform and a short explanation of what repeated, what changed, and why you rejected any section.

Do it with WebSerial →See the classroom use →Learn the PPG foundation →

Beginner1 sensorChoose one factor

2. What changes signal quality?

Question: How does one factor—placement, gentle pressure, ambient light, or motion—change the amount of usable signal?

ChangeChoose exactly one factor and define a baseline plus one changed condition.

Keep constantEverything else: participant, site, posture, attachment, sample rate, and duration.

RecordThree trials per condition, equal in length, with event markers and a written quality rule.

GraphCompare usable-signal percentage, amplitude, or peak-count errors across trials.

You’ll finish with: a table or graph comparing the two conditions, plus one limitation. “No clear difference” is a valid result.

Record the waveform →See the related study →Learn about PPG error sources →

IntermediateSaved dataNo new participant trials

3. Does sampling rate change the answer?

Question: What is lost when the same raw recording is represented with fewer samples?

ChangeDownsample one clean source recording to several lower rates.

Keep constantThe original physiology, time window, and analysis method.

RecordWaveform shape, detected peak times, BPM, and beat intervals for every rate.

GraphPlot the same time window at each rate and tabulate measurement differences.

You’ll finish with: a comparison showing which conclusions stayed stable and which changed as samples were removed.

Make a source recording →See the published study →Learn the signal-processing background →

Your fair-test method

Five steps are enough.

Ask
Write one question.

Baseline
Record a clean comparison.

Change one thing
Keep the rest constant.

Repeat and save
Keep raw data and trial labels.

Report
Show evidence, uncertainty, rejected data, and failure.

“No clear difference” is a valid result. It is more scientific than forcing a conclusion.

Copy this lab plan

Question: ___ Independent variable: ___ Constants: ___
Three trials: ___ Measurement: ___ Graph: ___
Result: ___ Uncertainty or limitation: ___

Advanced questions

Try these after you can record clean, repeatable data.

Breathing-related variation

Compare quiet natural breathing with comfortable gently paced breathing. Never use breath-holding or forced hyperventilation. Accuracy claims require a synchronized reference.

Relative arrival delay

Use two synchronized PPG channels and one consistent landmark. Report PPG-to-PPG delay and its spread; do not call it ECG-to-PPG PTT or infer blood pressure.

Pulse-rate variability

Plot each clean inter-beat interval against the next. Call the result PRV; it is not automatically identical to ECG-derived HRV.

Entering a competition? Ask first.

Ask your teacher or adult sponsor before collecting data. Fair rules change, and projects involving people—including some self-testing—may require review before experimentation. Testing other people may require prior IRB approval and consent or assent. Never collect or publish participant names or identifiable health data.

Read the current Society for Science / ISEF human-participant rules →

Know what this sensor measures.

PulseSensor records one green-light reflectance PPG channel. It does not measure SpO₂ or blood pressure and is not medical equipment. Breathing, timing, and variability observations remain experimental until validated against an appropriate reference.