Applying Robotics Learning in Unmanned Railway Crossing

Problems with unmanned railway crossing

In India, 61% of railway related fatalities are attributed to accidents at Unmanned Level Crossings as shown in fig.1.

Nearly two thirds of the total number of Level crossing accidents occur at unmanned Level Crossings and this proportion has been increasing ever since.

There are many ways to solve this problem. One solution could be to use manned crossing. Other one could be to use over bridges. But they have some drawbacks like making it manned will need more man power, cost, etc.

Moonpreneur students has created a passion project to solve this problem.

The project requires following items.

Required Items

• BBC Microbit and its cable
• 2 IR Sensors
• Servo Motor
• A toy train

(Any other object can also be used to mimic the action of train)

Age: 7-8 yrs

Let’s Start

Step1: Connecting IR Sensors

• Use a wire and connect one end to any pin of GND header in Microbit breakout board. Connect the other end with GND pin of IR sensor 1.

• Repeat the step for two more connections.

• Repeat the steps to connect another IR sensor.

NOTE: Calibrate the IR sensors by rotating the potentiometer such that it can sense the train/object from some appropriate distance.

Step2: Connecting Servo Motor

• Use a wire and connect one end to any pin of GND header in Microbit breakout board. Connect the other end with GND pin of servo motor.
• Repeat the step for two more connections.

NOTE: Make sure that the arm of servo is mounted vertically (facing upwards) when the servo is at 0 degree position in order to get it horizontal when rotated to 90 degree.

Step3: Programming 

The code monitors the passage of trains using infrared sensors. When a train enters the monitored area, it increments the count and closes the servo-controlled gate. When the train exits, it opens the gate.

Code

# Imports go at the top

from microbit import *

#*****************************

class Servo:

    def __init__(self, pin, freq=50, min_us=600, max_us=2400, angle=180):

        self.min_us = min_us

        self.max_us = max_us

        self.us = 0

        self.freq = freq

        self.angle = angle

        self.analog_period = 0

        self.pin = pin

        analog_period = round((1/self.freq) * 1000)  # hertz to miliseconds

        self.pin.set_analog_period(analog_period)




    def write_us(self, us):

        us = min(self.max_us, max(self.min_us, us))

        duty = round(us * 1024 * self.freq // 1000000)

        self.pin.write_analog(duty)

        sleep(100)

        self.pin.write_digital(0)  # turn the pin off




    def write_angle(self, degrees=None):

        if degrees is None:

            degrees = math.degrees(radians)

        degrees = degrees % 360

        total_range = self.max_us - self.min_us

        us = self.min_us + total_range * degrees // self.angle

        self.write_us(us)

#***********************************




# Initialize servo motor on pin 2

sv1 = Servo(pin2)

sv1.write_angle(0)  # Set initial angle of servo to 0 degrees




# Initialize variables to keep track of last state of IR sensors and train count

lastIR1state = 1

lastIR2state = 1

count = 0




# Function to handle actions when train enters

def entered():

    global lastIR2state

    while True:

        IR2state = pin1.read_digital()  # Read digital value from IR sensor 2

        if IR2state != lastIR2state:  # Check if state of IR sensor 2 has changed

            if IR2state == 1:  # If train exits (IR sensor detects no train)

                print("Train Exits")

                sv1.write_angle(0)  # Set angle of servo to 0 degrees (open position)

                sleep(200)  # Pause for 200 milliseconds

            lastIR2state = IR2state  # Update lastIR2state to current state

            break  # Exit the loop




# Main loop to continuously check state of IR sensor 1

while True:

    IR1state = pin0.read_digital()  # Read digital value from IR sensor 1

    if IR1state != lastIR1state:  # Check if state of IR sensor 1 has changed

        if IR1state == 0:  # If train enters (IR sensor detects train)

            print("Train Entered")

            sv1.write_angle(90)  # Set angle of servo to 90 degrees (closed position)

            sleep(200)  # Pause for 200 milliseconds

            count += 1  # Increment train count

        lastIR1state = IR1state  # Update lastIR1state to current state

        display.show(count)  # Display current train count on LED display

        entered()  # Call the entered function to handle train exit

Many pins of breakout board are available to add more features like a railway crossing sign.

References:

https://www.ispp.org.in/leveraging-technology-to-mitigate-traffic-congestion-at-manned-railway-crossings-in-india/

https://www.researchgate.net/figure/A-chart-showing-the-Loss-of-lives-in-train-accidents-in-percentage_fig1_306067468#:~:text=In%20India%2C%2061%25%20of%20railway,increasing%20ever%20since.%20