Line sensors

Eliobot's line sensors are infrared sensors that detect lines.

Use with Elioblocs

To use Eliobot line sensors on Elioblocs, we use blocks from the category.

Use with Python

With python, you must define each line sensor as an object. We have 5 sensors on the line sensor, they are connected to the following pins:

	Sensor 1	Sensor 2	Sensor 3	Sensor 4	Sensor 5
Pin	IO10	IO11	IO12	IO13	IO14

We use the reflected light to detect the line, we measure the ambient light and the reflected light to calculate the value.

The sensors return analog values.

Related examples

Elioblocs example

Here if we detect a line under sensor 3 (the middle sensor), we move forward.

---

Python example

from elio import Eliobot
import board
import time
import digitalio
import analogio
import pwmio

vBatt_pin = analogio.AnalogIn(board.BATTERY)

obstacleInput = [analogio.AnalogIn(pin) for pin in
                 (board.IO4, board.IO5, board.IO6, board.IO7)]

lineCmd = digitalio.DigitalInOut(board.IO33)
lineCmd.direction = digitalio.Direction.OUTPUT

lineInput = None

AIN1 = pwmio.PWMOut(board.IO36)
AIN2 = pwmio.PWMOut(board.IO38)
BIN1 = pwmio.PWMOut(board.IO35)
BIN2 = pwmio.PWMOut(board.IO37)

buzzer = pwmio.PWMOut(board.IO17, variable_frequency=True)

elio = Eliobot(AIN1, AIN2, BIN1, BIN2, vBatt_pin, obstacleInput, buzzer, lineInput, lineCmd)

line_sensor = [
    analogio.AnalogIn(board.IO10), # Sensor 1
    analogio.AnalogIn(board.IO11), # Sensor 2
    analogio.AnalogIn(board.IO12), # Sensor 3
    analogio.AnalogIn(board.IO13), # Sensor 4
    analogio.AnalogIn(board.IO14)  # Sensor 5
]

# Function to get a line sensor value
def getLine(line_pos):
    ambient = 0
    lit = 0
    value = 0

    # Measure reflected light
    obstacleCmd.value = True
    time.sleep(0.02)
    lit = lineInput[line_pos].value

    # Measure ambient light
    obstacleCmd.value = False
    time.sleep(0.02)
    ambient = lineInput[line_pos].value

    # Compute value
    value = ambient - lit

    return value
    
while True:
    if getLine(2) > 30000: # If sensor 3 detects a line
        elio.move_forward(100) # Move forward

Here if we detect a line under sensor 3 (the middle sensor), we move forward. The detection threshold is 30000, it is an approximate value, it must be calibrated for optimal operation.