7. Case 04: Urban noise detection

Level: level auto_fit

7.1. Goal

Make a noise detection point to detect the noise volume near the roadside using noise sensor.

7.2. Background

What is urban noise detection?

It is a system to detect noise near the road as noise pollution caused by cars on the road seriously affect the living standard of people. By installing a monitor to detect the noise volume near the roadside can help engineer to gather noise information and find solution to solve the problem in the future.

Noise detection operation

The noise sensor can detect the volume in dB near the roadside and show the volume on the OLED. A bar graph of sound intensity will be shown on the micro:bit.

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7.3. Part List

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7.4. Assembly step

Step 1

Attach the OLED to D1 model with M2 * 10mm screws and nuts.

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Step 2

Attach noise sensor to D1 model with M4 * 10mm screws and nuts.

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Step 3

Put together all the cardboard parts (D1-D2).

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Step 4

Assembly completed!

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7.5. Hardware connect

Connect Noise Sensor to P1 port of IoT:bit

Extend the connection of OLED to I2C connection port of IoT:bit

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7.6. Programming (MakeCode)

Step 1

Step 1. Initialize OLED screen and variable

  • Drag Initialize OLED with width:128, height: 64 to on start

  • Set Noise to 0 from variables auto_fit

Step 2. Show noise value on micro:bit LED

  • In block forever. Set noise to round get noise level (dB) at pin P1

  • Drag plot bar graph of … from Led and draw variable Noise into the plotted value. Set value up to 100

  • Drag Pause to the loop for wait for 0.5 second for next checking auto_fit

Step 3. Show the noise value on OLED screen

  • Snap clear OLED display from OLED to avoid overlap

  • Snap show string to the loop and show value of the variable Noise auto_fit

Full Solution

MakeCode: https://makecode.microbit.org/S73074-92559-00368-70628

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7.7. Results

After initializing WiFi extension board and OLED, micro:bit will show a bar graph for the sound intensity in a city.

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7.8. Think

Q1. How to make a notification if noise pollution problem is serious? i.e. showing red LED