Welcome to World of Module Sensor Kit repository
8.1 Running box
Note: Please use the double-headed data cable provided by us to connect the Micro:bit board and expansion board to the computer, otherwise it will not be possible to drive the servo due to insufficient power.
1. Learning target
In this lesson, we will use the micro:bit board, building blocks and sensor modules to build an running box.
When a person is detected passing by, the sensor will be triggered, and an alarm image will be displayed on the dot matrix.
Running box will swing its arms and move forward slowly.
2. Servo calibration
Before assembling the building blocks, we need to use code to calibrate the servo to a fixed angle.
If calibration is not calibrated before using, it is easy to jam the servo during use and cause the steering gear to stall and damage the servo.
Calibration method:
2.1 Connect the brown line of the servo to GND (black), the red line of the servo to VCC (red), and the yellow line of the servo to IO on expansion board.
The left servo is connected to P1, and the right servo is connected to P2. As shown below.
2.2 Then connect the computer to the Micro:bit board and expansion board through the double-head micro USB cable we provided.
2.3 Download the servo calibration code (Servo-calibration-running-box.py) to the micro:bit board.
2.4 When a "1" pattern is displayed on the dot matrix of the Micro:bit board, it means the servo be calibrated successfully.
3. Building blocks assembly
Please follow the steps we provide to assemble the building block models.
Pay attention to the installation direction of the servo when assembling, otherwise the servo will be damaged due to the wrong angle of the servo after running the program.
After the assembly is completed, please check the wiring of the servo as shown below.
4. About wiring
5. About code
from microbit import *
import music
import WOM_Sensor_Kit
people_1 = Image("00900:09990:90909:09090:09090")
people_2 = Image("00900:09990:90909:09090:90009")
while True:
WOM_Sensor_Kit.WOM_servo360(pin1,180)
WOM_Sensor_Kit.WOM_servo360(pin2,180)
if WOM_Sensor_Kit.WOM_pir(pin0) == 1:
display.show(people_1)
WOM_Sensor_Kit.WOM_servo360(pin1,130)
WOM_Sensor_Kit.WOM_servo360(pin2,130)
sleep(500)
display.show(people_2)
WOM_Sensor_Kit.WOM_servo360(pin1,220)
WOM_Sensor_Kit.WOM_servo360(pin2,220)
sleep(500)
display.show(people_1)
WOM_Sensor_Kit.WOM_servo360(pin1,130)
WOM_Sensor_Kit.WOM_servo360(pin2,130)
sleep(500)
display.show(people_2)
WOM_Sensor_Kit.WOM_servo360(pin1,220)
WOM_Sensor_Kit.WOM_servo360(pin2,220)
sleep(500)
if WOM_Sensor_Kit.WOM_pir(pin0) == 0:
display.show(Image.YES)6.Writing and download code
6.1 You should open the Mu software, and enter the code in the edit window, , as shown below.
Note! All English and symbols should be entered in English, use the Tab key (tab key) to indent and the last line must be a space.
6.2 You can click the “Check” button to check if our code has an error.
If a cursor or underline appears on a line, it indicates a syntax error, please check and modify. If there is no error in the program, the bottom left of the interface will prompt that there is no problem in detection.
6.3 Click the ‘REPL’ button to check whether the WOM_Sensor_Kit Python library has been downloaded.
If not, please refer to [Preparation before class] --> [Python Programming Guide] .
6.4 After the program is written, use a micro USB cable to connect the computer and the micro:bit board. Please click the ‘Flash’ button to download the program to the micro:bit motherboard (You need to click the ‘REPL’ button again to close the function of importing library files before you download the program).
6.5 If the download failed, please confirm whether the micro:bit is connected to the computer through the micro USB data cable, and confirm whether the WOM_Sensor_Kit Python library has been imported.
7. Experimental phenomena
After the program is downloaded successfully. We can see a love heart displayed on the Micro:bit board, indicating that it is still being initialized, and the human infrared module cannot be triggered at this time.
After 5 seconds, Micro:bit shows a smile pattern, it means that the module is in normal working condition. When the human body infrared module detects that there is a human body moving, the dot matrix will switch to an alarm pattern, the buzzer will play the alarm sound, and the escape box will swing its arms and move forward slowly.
Note: The detection angle of the human body infrared sensor module is 120°.
The recognition effect is the best when the human body is directly in front.
If you need to restart, press the reset button on the back of the micro:bit board.