1.11. Case 09: Control the Car with an Indicator#

1.11.1. Purpose#


Build a car with the bricks and control it with the AI Lens via the indicators.

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Materials Required and Connection Diagram#

  • Connect the AI Lens to the IIC port and the two motors on M1,M4 ports on the Nezha expansion board as the picture shows.

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  • Build a car with the bricks below.

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1.11.2. MakeCode Programming#


Step 1#

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

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We need to add a package for programming. Click “Extensions” in the bottom of the drawer and search with “PlanetX” in the dialogue box to download it.

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Then search with “nezha” to download this extension.

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Note: If you met a tip indicating that the codebase will be deleted due to incompatibility, you may continue as the tips say or build a new project in the menu.

Step 2#

Code as below:#

  • Initialize the AI lens while on start and switch its function to Card recognition.

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  • Get one image from the AI Lens, if the card is detected, judge the distance from the card to the car. If it is a long distance, the lens would get the value of the “X-axis”and respond it by adjusting the speed of the two motors to keep the image in the middle of the lens.

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  • If the car is near to the card, judge the instructions(symbols) on the card. If it is a turn-right instruction, make the car turn right by adjusting the speed of the motors, then program to get 3 images from the lens and give no instruction to these three pictures to clear the caches. If it is a stop instruction, make the car stop moving by adjusting the speed of the motors, then program to get 3 images from the lens and give no instruction to these three pictures to clear the caches.

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  • If the AI Lens does not detect any image, the car moves forward.

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Completed Code:

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Result#

  • Drive the car and make it move with the instructions.