Noise Detector

Introduction

This project guides you to build a simple noise detector using a micro:bit board. By leveraging the onboard microphone module to collect real-time environmental sound signals, the noise level is visualized on an OLED matrix after data processing, enabling intuitive monitoring of ambient noise.

Teaching Objectives

• Understand how the micro:bit detects noise intensity.
• Master basic programming skills for controlling LED lights using the micro:bit.

Teaching Preparations

Before starting the lesson, ensure you have prepared the following materials:

Image	Name	Quantity	Remarks
	Smart Home Explorer Kit	1
	micro:bit	1	Prepare separately
	PC	1	Prepare separately

These materials will provide a comprehensive hands-on experience to ensure smooth progress in subsequent operations and learning. If you have prepared the above, we can proceed to the next step.

Course Introduction

Acoustic Environment Mini-Lesson

• Normal conversation: 40–60 dB
• Urban traffic noise: 70–85 dB (exceeding 80 dB may damage hearing)
• Industrial equipment noise: Over 100 dB (requires protective gear)

Interactive Thinking: Observe noise sources around you and reflect on the significance of noise monitoring for environmental protection and health management.

Project Production

Hardware Connection

Connect the OLED display to the I²C interface of the Petal Base Expansion Board.https://makecode.microbit.org/)

Create a new project.

Enter the project name and click Create.

Add Software Libraries

In the makecode programming interface, click Extensions in the Toolbox.

Search for petal in the pop-up window and select the petal software library.

Write the Program

Example program: https://makecode.microbit.org/_XDP81wYyXbf8

You can also directly download the program via the embedded iframe below:

How to Download the Program to micro:bit?

Connect the PC to the micro:bit V2 using a USB cable.

After a successful connection, a drive named MICROBIT will appear on the computer.

Click the icon in the lower-left corner，and selectConnect Device。

Click。

Click。

In the pop-up window, select BBC micro:bit CMSIS-DAP and click Connect. The micro:bit is now successfully connected.

Click to download the program.

Results

After powering on, the OLED display shows the current noise level, with a bar graph on the LED matrix for visual indication.

Extended Knowledge

Noise, as a "hidden pollutant" in modern society, profoundly impacts human life, health, and the environment. Below is a multi-dimensional analysis of its effects:

I. Health Hazards

1. Auditory System Damage
   • Hearing Loss: Long-term exposure to noise above 85 dB (e.g., traffic, industrial machinery) damages cochlear hair cells, leading to noise-induced deafness. For example, construction workers and airport ground staff have significantly higher hearing impairment rates than the general population 4.
   • Tinnitus: Over 40% of long-term noise-exposed individuals experience persistent tinnitus, affecting sleep and concentration.
2. Cardiovascular Impact
   • Hypertension: Noise stimulates the sympathetic nervous system, increasing adrenaline secretion and potentially causing hypertension. Studies show residents near busy roads have a 15–20% higher hypertension incidence than those in quiet areas.
   • Arrhythmia: Sudden intense noise (e.g., aircraft takeoff) may trigger irregular heartbeats, elevating heart attack risks.
3. Neurological and Psychological Effects
   • Sleep Disorders: Noise above 30 dB disrupts light sleep, causing insomnia and fragmented sleep. Chronic sleep deprivation may lead to anxiety and depression.
   • Reduced Concentration: Office noise exceeding 50 dB decreases work efficiency by 20% and increases error rates by 30%.
4. Other Physiological Impacts
   • Digestive Issues: Noise may suppress gastrointestinal function via the neuroendocrine system, causing indigestion and ulcers.
   • Child Development: High-decibel exposure during fetal development or infancy may impair language and cognitive abilities.

II. Daily Life Interference

1. Communication and Social Barriers
   • Noise Spiral Effect: Public spaces exceeding 65 dB force louder conversations, leading to social fatigue over time.
   • Conference Call Accuracy: Background noise above 55 dB reduces information transfer accuracy by 40%.
2. Diminished Living Quality
   • Urban Complaints: Construction and traffic noise account for over 60% of urban complaints, severely affecting comfort.
   • Sleep Loss: Airport residents lose 1.5 hours of sleep nightly due to nighttime flights.
3. Ecological Damage
   • Wildlife: Ocean noise (e.g., shipping) disrupts cetacean sonar, hindering feeding and reproduction, even causing strandings.
   • Birds: Urban noise forces birds to adjust song frequencies, potentially lowering mating success and territorial defense.

III. Production and Safety Risks

1. Industrial Efficiency
   • Error Rates: Factory noise above 85 dB increases worker errors by 25% and accident risks.
   • Precision Issues: Noise may reduce calibration accuracy of precision instruments, affecting product quality.
2. Public Safety Risks
   • Emergency Alert Masking: Traffic noise may obscure ambulance/fire truck sirens, delaying rescues.
   • Community Conflicts: Construction noise often triggers disputes and collective complaints.

IV. Economic Costs

1. Healthcare Expenditures
   • WHO Estimates: Europe incurs over €100 billion annually in noise-related health costs, including medical expenses and productivity loss.
   • U.S. Studies: Noise pollution causes ~$40 billion in annual losses, primarily from hearing damage compensation and reduced efficiency.
2. Urban Planning Costs
   • Noise Mitigation: Cities invest heavily in sound barriers and low-noise roads. For example, Tokyo’s highway sound walls cost $20 million per kilometer.
   • Property Depreciation: Airport-adjacent properties lose 20–30% value due to noise, impacting local economies.

V. Mitigation Strategies

1. Personal Protection
   • Use noise-canceling headphones/earplugs (e.g., commuting, construction sites).
   • Choose low-noise appliances (e.g., energy-efficient refrigerators, silent fans).
2. Urban Planning Optimization
   • Implement "acoustic environmental functional zoning" to separate residential and industrial areas.
   • Promote green buildings with soundproof materials (e.g., double-glazed windows, acoustic panels).
3. Technological Innovation
   • Develop low-noise transportation (e.g., electric vehicles, quieter aircraft engines).
   • Install vibration-damping and soundproofing equipment in industrial machinery.
4. Policy and Regulation
   • Standards: China’s Social Ambient Noise Emission Standards set a 40 dB nighttime limit for residential areas.
   • Complaint Systems: Strengthen noise monitoring and enforcement for construction and traffic.

Conclusion Noise pollution has become a global environmental concern with far-reaching health, social, and economic impacts. Reducing noise requires individual behavior change, technological innovation, and policy coordination to achieve "quiet cities" and sustainable living. As WHO states: "Quiet is a fundamental human right and a prerequisite for a healthy ecosystem."