3. Case 22: Balls Tracking with TPBot

3.1. Purpose

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• Use TPBot to build a ball-tracking car.

3.2. Materials required

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• 1 x TPBot

• 1 x AI Lens

3.3. Hardware Connections

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Connect the AI Lens to the IIC port on TPBot.

3.4. Software

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MicroSoft MakeCode

3.5. MakeCode Programming

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

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

• We need to add a package for programming the AI Lens kit. Click “Extensions” in the bottom of the drawer and seach with https://github.com/elecfreaks/pxt-PlanetX-AI in the dialogue box to download it.

Sample Code

• Initialize the AI lens kit in the On start brick and switch its function to balls recognition.

• In forever brick, get an image from the AI lens and adjust TPBot’s movement by the balls recognized in the lens.

• Complete code:

Link

• Link: https://makecode.microbit.org/_TY634U7x5RaH

• You may also download it directly here:

3.6. Python Programming

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Add TPBot extension: https://www.elecfreaks.com/learn-cn/microbitKit/TPbot_tianpeng/TPbot-python.html

Add AI Lens extension: https://www.elecfreaks.com/learn-cn/microbitplanetX/ai/Plant-X-EF05035-python.html

Code

from microbit import *
from AILens import *
from TPBot import *

tp = TPBOT()
ai = AILENS()
# Set the function of AI Lens in balls recognition
ai.switch_function(Ball)

while True:
    # Get an image
    ai.get_image()
    buff = ai.get_ball_data()
    # "buff[1]" means the Y coordinates data of the ball detected in AI lens 
    if (buff[1] > 80):
        # "buff[0]" means the X coordinates data of the ball detected in AI lens
        if (buff[0]< 80):
            tp.set_motors_speed(-30,0)  
        elif (buff[0] > 144):
            tp.set_motors_speed(0,-30)
        else:
            tp.set_motors_speed(25,25)
    else:
        tp.set_motors_speed(0,0)

Result

The TPBot moves with the ball and it stops while walking in the right front of the ball.

3.7. Exporation

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3.8. FAQ

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Q: TPBot doesn’t work with the sample code.
A: It is probably due to the lack of battery power, please try adding the speed of the TPBot or replacing with new batteries.
Q: The AI Lens is not working, and it does not go to the function page with the sample code.
A: Please try replacing with new batteries.

3.9. Relevant File

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