[{"id":2895,"name":"9.Tracking","moduletypeid":459,"content":"

<\/p>

! Note: This experiment must be done indoors to reduce the interference of sunlight on the infrared sensor.<\/span><\/strong><\/p>

Learning goal<\/span>:<\/span><\/span><\/strong><\/em><\/p>

This lesson learns how to <\/span>use tracking sensor <\/span>by Python programming.<\/span><\/p>

Code:<\/span><\/strong><\/em><\/p>

\"image.png\"<\/p>

1) <\/span>Import the library needed for this lesson from micro:bit, display is used for dot matrix display, Image calls the built-in image, pin12 is the pin of the body colorful lights, neopixel drives the body colorful lights, and tinybit controls the car.<\/span><\/p>

2) <\/span>display.show (Image.<\/span><\/strong>NO<\/span><\/strong>)<\/span><\/strong>: Display a <\/span>“X”<\/span> on micro:bit dot matrix.<\/span><\/p>

3) <\/span>trakeL<\/span><\/strong> = tinybit.traking_sensor_L()<\/span><\/strong>：<\/span>Read the data from the left <\/span>tracking<\/span> sensor, return <\/span>T<\/span>rue when a black line is detected, return <\/span>F<\/span>alse when a white line is detected, and save the read result to the<\/span> <\/span>variable<\/span> <\/span>trakeL<\/span>.<\/span><\/p>

4) <\/span>trakeR<\/span><\/strong> = tinybit.traking_sensor_R()<\/span><\/strong>：<\/span>Read the data from the <\/span>right tracking<\/span> sensor, return <\/span>T<\/span>rue when a black line is detected, return <\/span>F<\/span>alse when a white line is detected, and save the read result to the<\/span> <\/span>variable<\/span> <\/span>trakeR<\/span>.<\/span><\/p>

5) <\/span>When trakeL and trakeR are True at the same time, that is, black lines are detected on both sides, a smiling face is displayed; if a black line is detected on the left, L is displayed; if a black line is detected on the right, R is displayed; When there is a black line, the character X is displayed.<\/span><\/p>

Programming and downloading<\/span>:<\/span><\/span><\/strong><\/em><\/p>

1.<\/span>You should open the Mu software, and enter the code in the edit window, , as shown below. <\/span><\/p>

Note! All English and symbols should be entered in English, and the last line must be a space.<\/span><\/strong><\/p>

\"image.png\" <\/span><\/p>

2.<\/span>You can click the <\/span>“Check”<\/span><\/strong> button to check if our code has an error. If a line appears with a cursor or an underscore, the program indicating this line is wrong.<\/span><\/p>

\"image.png\" <\/span><\/p>

3.Click <\/span>“REPL”<\/span><\/strong> button,check whether the tinybit library has been downloaded. If not, please refer to the [preparation before class]---> [Python programming]<\/span><\/p>

\"image.png\"\/ <\/span><\/p>

4.Click the <\/span>“Flash”<\/span><\/strong> button to download the program to micro:bit board.<\/span><\/p>

\"image.png\" <\/span><\/p>

If the program is wrong or the experimental phenomenon is wrong after downloading, please confirm whether you have downloaded the Buildingbit libraryhex file we provided to the micro: bit board.<\/span><\/p>

For the specific method of adding library files, please refer to <\/span>【<\/span><\/span>1.Preparation before class<\/span>】<\/span><\/span>---<\/span>【<\/span><\/span>P<\/span>ython programming<\/span>】<\/span><\/span><\/p>

Experimental phenomena:<\/span><\/strong><\/em><\/p>

After <\/span>download is complete, open the power switch<\/span>. <\/span><\/p>

When a black line is detected by the left line sensor, “L” is displayed on the LED dot matrix. When a black line is detected by the right sensor, “R” is displayed on the LED dot matrix. When a black line is detected on both sides at the same time, a smile is displayed.<\/span><\/p>

When the black line is no detected, “X” is displayed.<\/span><\/p>","videotype":2,"videoname_1":"``http:\/\/www.yahboom.net\/xiazai\/Tiny_bit\/10.micro python course\/1.Basic course\/Tracking.py","videoname_2":"``","videoname_3":"``","videoname_4":"``","videoname_5":"``","videoname_6":"``","newimg":0,"dataurl":"","customurl":"","documentation_switch":"","classificationid":115,"paixu":10,"adddate":"1564044339"},[["","","http:\/\/www.yahboom.net\/xiazai\/Tiny_bit\/10.micro python course\/1.Basic course\/Tracking.py","Tracking.py"]]]