Blow Hot, Blow Cold (Smart Digital Stethoscope & Spirometer)
Source: Stemoto Original
Dr. Zakir Husain's story explores breathing and temperature regulation. Build a electronic stethoscope to listen to heartbeats and a turbine spirometer to measure lung breathing capacity and breath temperature.
Categorisation
Props & Materials Required
- •Digital electronic stethoscope chest piece microphone module
- •Turbine airflow spirometer wheel with optical sensor
- •DS18B20 breath temperature sensor
- •ESP32 controller board
- •0.96-inch OLED display screen
- •DFPlayer Mini MP3 module + 3W speaker
Step-by-Step Instructions
Listen to Heartbeats with Stethoscope
Place digital stethoscope chest piece over heart. Speaker amplifies real 'LUB-DUB' heartbeats! OLED displays 'Heart Rate: 78 BPM'.
Blow into Spirometer Turbine
Take a deep breath and blow into the spirometer tube.
Measure Lung Capacity & Air Speed
Turbine wheel spins. OLED displays 'Lung Capacity: 2.2 Liters | Airflow: 4.5 L/s'.
Blow Hot vs Blow Cold Science
Blow gently on breath temp sensor (36.5°C warm air). Blow fast with pursed lips — air cools down! Speaker explains thermodynamics.
Why It Works & Notes
Blow Hot, Blow Cold demonstrates why blowing air cools hot tea (evaporative cooling) but warms cold hands in winter. Constructing digital stethoscopes and lung spirometers connects human physiology with fluid thermodynamics.
Looking Around Class 5 Chapter 15: Blow Hot, Blow Cold | STEM Tech: Electret Microphone Heartbeat Amplification & Turbine Airflow Spirometry Telemetry — medical diagnostic devices.