Team Spark:

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Published April 26, 2026 © GPL3+

StressGuard - Exam Stress Monitor using Raspberry Pi Pico

Stressed in exams? StressGuard detects rising stress in real time & alerts you before panic sets in. Built on Pi Pico. Fully offline.

BeginnerWork in progress6 hours7

StressGuard - Exam Stress Monitor using Raspberry Pi Pico

Things used in this project

Hardware components

Raspberry Pi 3 Model B

Rotary potentiometer (generic)

Buzzer

Seeed Studio Grove - OLED Display 0.66" (SSD1306)- IIC - 3.3V/5V

Resistor 220 ohm

5 mm LED: Red

Software apps and online services

MicroPython

wokwi

thonny

Hand tools and fabrication machines

Breadboard, Solderless

Digilent Mastech MS8217 Autorange Digital Multimeter

Story

The Problem

Every student has experienced it — sitting in an exam, knowing the answer, and suddenly the mind goes blank. Stress peaks, panic sets in, and performance drops. The worst part? By the time you consciously feel anxious, your body has already been in a stress response for several minutes.

There is no affordable, real-time device built specifically for students that detects rising stress early and alerts them before panic sets in.

Why We Built StressGuard

We are 2nd semester engineering students who have faced exam stress firsthand. We wanted to build something that actually solves a real problem — not just another LED blinking project.

StressGuard monitors stress levels in real time and gives a silent alert the moment stress starts rising — giving the student time to breathe and recover before it peaks.

How It Works

StressGuard reads a variable resistance signal that represents skin conductance — the same principle used in medical-grade stress detection. In this prototype, a 10kΩ potentiometer simulates the variable signal that a GSR sensor would produce in the final version.

The Raspberry Pi Pico reads this signal through its ADC pin (GP26) at 20 samples per second. The value is converted to a stress percentage and compared against three levels:

Calm — below 40% — no alert

Moderate — 40% to 70% — LED blinks, buzzer beeps softly

High Stress — above 70% — LED blinks rapidly, buzzer beeps loudly

The current stress level and status is displayed live on a 0.96 inch SSD1306 OLED screen along with a visual progress bar.

What Makes It Different

Unlike smartwatches and fitness bands, StressGuard is:

Distraction free — no notifications, no apps, does only one job

Exam friendly — no WiFi, no Bluetooth, allowed where smartwatches are banned

Fully offline — all data stays on the device, nothing goes to any server

Student budget — built for under ₹3000, not ₹35, 000

Personalizable — code is fully open and customizable

Prototype Note

This prototype uses a potentiometer to simulate the variable resistance signal of a GSR sensor. The circuit and code are fully compatible with a real GSR module — replacing the potentiometer requires absolutely no code changes.

Tech Stack

Microcontroller — Raspberry Pi Pico (RP2040)

Language — MicroPython

Display — SSD1306 0.96" OLED via I2C

Alert — Passive buzzer via PWM + Red LED

Simulation — Wokwi online simulator

IDE — Thonny

Future Scope

Add MAX30102 heart rate sensor for higher accuracy
Upgrade to Pico W for WiFi and live phone dashboard
Data logging to find personal stress patterns over time
Machine learning model to predict stress before it peaks
Guided breathing exercise triggered automatically on high stress
Classroom version — teacher sees anonymous stress heatmap of entire class

STRESSGUARD

HIGH STRESS LEVEL

Code

StressGuard

from machine import Pin, ADC, PWM, I2C
import utime
from ssd1306 import SSD1306_I2C    # OLED display library

# Setup
sensor = ADC(26)
led = Pin(15, Pin.OUT)
buzzer = PWM(Pin(14))

# OLED Setup
i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)
oled = SSD1306_I2C(128, 64, i2c)   # 128x64 pixel display

def get_stress(raw):
    return int((raw / 65535) * 100)

def beep(frequency, duration):
    buzzer.freq(frequency)
    buzzer.duty_u16(30000)
    utime.sleep(duration)
    buzzer.duty_u16(0)

def blink(times, on_time, off_time):
    for i in range(times):
        led.value(1)
        utime.sleep(on_time)
        led.value(0)
        utime.sleep(off_time)

def show_display(stress, status):
    oled.fill(0)                          # Clear screen

    # Title
    oled.text("STRESS MONITOR", 0, 0)
    oled.text("--------------", 0, 10)

    # Stress percentage
    oled.text("Level: " + str(stress) + "%", 0, 22)

    # Status text
    oled.text("Status: " + status, 0, 34)

    # Progress bar (shows stress visually)
    bar_width = int((stress / 100) * 120)  # Max 120 pixels wide
    oled.rect(0, 50, 120, 10, 1)           # Outer box
    oled.fill_rect(0, 50, bar_width, 10, 1) # Filled bar

    oled.show()                            # Push to screen

while True:
    raw_value = sensor.read_u16()
    stress = get_stress(raw_value)

    print("Stress Level:", stress, "%")

    if stress < 40:
        led.value(0)
        buzzer.duty_u16(0)
        show_display(stress, "CALM")
        print("Status: CALM")
        utime.sleep(0.5)

    elif stress < 70:
        show_display(stress, "MODERATE")
        print("Status: MODERATE")
        blink(2, 0.4, 0.4)
        beep(500, 0.2)
        utime.sleep(0.3)

    else:
        show_display(stress, "HIGH!")
        print("Status: HIGH STRESS")
        blink(3, 0.1, 0.1)
        beep(1000, 0.1)
        beep(1000, 0.1)
        utime.sleep(0.2)