5. case 03:Thermometer

5.1. Our Goal


  • Use watch kit to create a wearable thermometer.

5.2. Material


  • 1 x Watch kit

5.3. Hardware Connection


Assemble our watch kit directly just like the picture below.

../../_images/vOZpBF4.jpg

5.4. Software


Microsoft Makecode

5.5. Programming


Step 1

  • Create a variable flag. Initialize this variable to 0 when we startup our micro:bit. When button A is pressed, set the flag to 1.

../../_images/HaGGibi.png

Step 2

  • Create a forever loop and insert show icon block with a heart under it. If the flag equals 1, then assign the temperature value to the variable Tem.

  • If the variable Tem is beyond 30 degrees, display a crying face and show string “So Hot”。And then delay 0.5 second after displaying the temperature.

../../_images/HzZW19S.png

Step 3

  • If the variable Tem is under 20 degrees, display a crying face and show string “So cold”. And then delay 0.5 second after displaying the temperature.

  • If the temperature is among 20 degrees to 30 degrees, then display a smile face and delay for 0.5 second after showing the temperature.

  • Set flagto 0 to exit the function above.

../../_images/C3eAQ3I.png

5.6. Program


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5.7. Result


  • We can see a smile face and temperature on micro:bit screen.

../../_images/I7ZCzeC.gif

5.8. Think


5.9. FAQ


Q: Sometimes the temperature is obviously under 20 degrees, why the displayed number is much higher? A: Because the temperature obtained by micro:bit is the temperature of main chip, instead of environment temperature. When micro:bit runs for a long time, the chip will be heated significantly.

5.10. Relative Readings