20. Case 10 Smart Crashproof Car

20.1. Purpose

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

20.2. Materials

• 1 x Ring:bit Car kit

• 1 x micro:bit

• 1 x Sonar:bit

20.3. Hardware Connection

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

20.4. Software Programming

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

20.5. 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:

20.6. Result

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

20.7. 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.

20.8. FAQ