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Case 10 Smart Crashproof Car

Purpose​

  • Make a smart crashproof car with a Sonar:bit.

Materials​

Hardware Connection​

  • Connect the left servo to P1, right servo to P2 and Sonar:bit to P0 of the Ring:bit.

Software Programming​

Microsoft makecode online coding https://makecode.microbit.org/#

Software​

Step 1​

  • Click "Advanced" in the drawer of MakeCode to see more choices.

  • We need to add a package for programming the kit. Click "Extensions" in the drawer and search “ringbit" in the dialogue box to download it.

  • We also need to add a package for programming the Sonar:bit. Click "Extensions" in the drawer and search “https://github.com/elecfreaks/pxt-sonarbit" in the dialogue box to download it.

Note: if you are informed that it will be deleted due to incompatibility of the codebase, you can go on with the tips or create a new project in the menu.

Step 2​

  • Drag the pins selection bricks for servos in the On start brick, the pins numbers are set according to the actual connection port.
  • Move forward at full speed.

Step 3​

  • Set variate sonar in the forever brick and read the detected value from the Sonar:bit to it.
  • Drag the if brick and judge if the value given by sonar is below 10 and not equal to 0.
  • If yes, set the speed of right wheel to 100 and the left to 0 to turn left with 500ms for obstacle avoidance.
  • If not, move forward at full speed.

Reference​

Links: https://makecode.microbit.org/_RTwFcMeA1MMY

You can also download it below:

Result​

  • The Ring:bit car turns left automatically when detecting any obstacle 10cm in front of it.

Exploration​

  • Question: Why we need to judge if the value is not 0 ?
  • Answer: The detection value is also 0 if beyond the detection scope of Sonar:bit.

FAQ​