11. Case 09: Noise Detection Device in the Library#

11.1. Introduction#


  • Noise has always been a serious problem in library management. If you stay in an environment above 85db for more than 8 hours, it will damage the hearing ability, although under normal circumstances the library will not have such a large source of noise , but the impact to readers from smaller noise cannot be ignored in the library . Thus, we can make a library noise detection device to remind people of the current environmental noise level.

11.2. Function#


  • Detect the noise level from the sound sensor on the micro:bit and have the value displayed on the OLED screen, program to light on the LED with the equivalent color.

11.4. Picture#


../../_images/microbit-Smart-City-Kit-case-01-02.png

11.5. Hardware Connection#


Connect the green led to P1, the yellow to P2, the red to P9 and the OLED to the IIC port on IoT:bit.

../../_images/microbit-Smart-City-Kit-case-04-03.png

11.6. Software Program#


Click “Advanced” in the MakeCode drawer to see more choices.

../../_images/microbit-Smart-City-Kit-case-01-04.png

For programming, we need to add a package: click “Extensions” at the bottom of the MakeCode drawer and search with “iot-environment-kit” in the dialogue box to download it.

../../_images/microbit-Smart-City-Kit-case-01-05.png

Notice: If you met a tip indicating that some codebases would be deleted due to incompatibility, you may continue as the tips say or create a new project in the menu.

11.7. Program#


Initialize the OLED and display the sound level on the OLED screen.

../../_images/microbit-Smart-City-Kit-case-09-07.png

If the sound level is below 100, program to light on the green led, if it’s below 150, program to light on the yellow led; or to light on the red led.

../../_images/microbit-Smart-City-Kit-case-09-08.png

Link: https://makecode.microbit.org/_2D82PVTC2Vhr

11.8. Result#


  • Different LEDs are lightened in accordance with the equivalent sound level.