Introduction
Maker Line sensor is designed for line following robot application. It works at 3.3V and 5V make it suitable to be used with Arduino boards, Raspberry Pi, ESP32 and micro:bit. This tutorial is using Raspberry Pi board and python code. Before we start, I recommend you to understand the basic of line following robot. You can refer to this tutorial:
Video
This video is about Raspberry Pi line following robot with Maker Line sensor.
Hardware Preparation
This is the list of items used in the video.
Sample Program
This is the python code for Raspberry Pi line following robot with Maker Line. You may need to adjust the speed (try and error) based on your hardware.
| from gpiozero import Button, Buzzer, LineSensor | |
| from time import sleep | |
| import pigpio | |
| from os import system | |
| pi = pigpio.pi() | |
| sw1 = Button(21) | |
| sw2 = Button(16) | |
| sw3 = Button(20) | |
| buzzer = Buzzer(26) | |
| sensorD1 = LineSensor(27) | |
| sensorD2 = LineSensor(22) | |
| sensorD3 = LineSensor(25) | |
| sensorD4 = LineSensor(12) | |
| sensorD5 = LineSensor(13) | |
| M1A = 18 | |
| M1B = 17 | |
| M2A = 3 | |
| M2B = 2 | |
| pi.set_mode(M1A, pigpio.OUTPUT) | |
| pi.set_mode(M1B, pigpio.OUTPUT) | |
| pi.set_mode(M2A, pigpio.OUTPUT) | |
| pi.set_mode(M2B, pigpio.OUTPUT) | |
| def readMakerLine(): | |
| global sensorReading | |
| sensorString = "" | |
| sensorReading = 1*(sensorD5.value) + \ | |
| 2*(sensorD4.value) + \ | |
| 4*(sensorD3.value) + \ | |
| 8*(sensorD2.value) + \ | |
| 16*(sensorD1.value) | |
| if sensorReading < 16: | |
| sensorString = "0" | |
| if sensorReading < 8: | |
| sensorString = sensorString + "0" | |
| if sensorReading < 4: | |
| sensorString = sensorString + "0" | |
| if sensorReading < 2: | |
| sensorString = sensorString + "0" | |
| sensorString = sensorString + "{0:b}".format(sensorReading) | |
| print("Maker Line: " + sensorString) | |
| def robotMove(speedLeft, speedRight): | |
| if speedLeft > 0: | |
| pi.set_PWM_dutycycle(M1A, 0) | |
| pi.set_PWM_dutycycle(M1B, speedLeft) | |
| else: | |
| pi.set_PWM_dutycycle(M1A, abs(speedLeft)) | |
| pi.set_PWM_dutycycle(M1B, 0) | |
| if speedRight > 0: | |
| pi.set_PWM_dutycycle(M2A, 0) | |
| pi.set_PWM_dutycycle(M2B, speedRight) | |
| else: | |
| pi.set_PWM_dutycycle(M2A, abs(speedRight)) | |
| pi.set_PWM_dutycycle(M2B, 0) | |
| def sw1Pressed(): | |
| global robotGo | |
| robotGo = True | |
| buzzer.beep(0.1, 0.1, 1) | |
| def sw2Pressed(): | |
| global robotGo | |
| robotGo = False | |
| buzzer.beep(0.1, 0.1, 1) | |
| sw1.when_pressed = sw1Pressed | |
| sw2.when_pressed = sw2Pressed | |
| sensorReading = 0 | |
| robotGo = False | |
| buzzer.beep(0.1, 0.1, 2) | |
| try: | |
| while True: | |
| if robotGo == False: | |
| robotMove(0, 0) | |
| else: | |
| readMakerLine() | |
| # You can adjust motor speed based on your hardware | |
| if sensorReading == 0b00100 or sensorReading == 0b01110: | |
| robotMove(40, 40) | |
| elif sensorReading == 0b01100: | |
| robotMove(30, 40) | |
| elif sensorReading == 0b00110: | |
| robotMove(40, 30) | |
| elif sensorReading == 0b11100: | |
| robotMove(20, 40) | |
| elif sensorReading == 0b00111: | |
| robotMove(40, 20) | |
| elif sensorReading == 0b11000: | |
| robotMove(10, 40) | |
| elif sensorReading == 0b00011: | |
| robotMove(40, 10) | |
| elif sensorReading == 0b10000: | |
| robotMove(0, 40) | |
| elif sensorReading == 0b00001: | |
| robotMove(40, 0) | |
| elif sensorReading == 0b11111: | |
| robotMove(30, 30) | |
| if sw3.is_pressed: | |
| robotMove(0, 0) | |
| sleep(1) | |
| buzzer.beep(0.2, 0.2, 3) | |
| sleep(1) | |
| system('sudo shutdown -h now') | |
| except KeyboardInterrupt: | |
| buzzer.off() | |
| robotMove(0, 0) |
Thank You
References:
Thanks for reading this tutorial. If you have any technical inquiry, please post at Cytron Technical Forum.
