Quad RGB Line Detection with mBlock

Quad RGB Sensor and Line Detection

• This video focuses on how the quad RGB sensor detects lines, which is essential for building a line follower robot.
• The video does not include coding, but explains the fundamental concepts behind the sensor's operation.

Quad RGB Sensor in mBlock

• The quad RGB sensor can be found in the mBlock web editor under the OT2 robot's extensions.
• In mBlock, the quad RGB sensor block has three settings: sensor ID, detection mode, and status value.
• The sensor ID is used to differentiate between multiple quad RGB sensors.
• The detection mode setting is set to "line" for line detection.
• The status value setting provides a numerical representation (0-15) of what the sensor detects, with corresponding binary form.

Quad RGB Sensor Overview

• The Quad RGB sensor module contains four sensors: L2, L1, R1, and R2.
• Quad means four.
• Each of the four sensors can detect a line underneath it, and also detect the color of the surface underneath it.
• Color detection is determined by measuring the amount of reflected red, green, and blue light.

Sensor Arrangement and Line Detection Logic

• The sensors L1 and L2 are on the left side of the sensor module, and R1 and R2 are on the right side.
• L1 and R1 are closer to the center than L2 and R2.
• Each sensor returns a '0' if no line is detected and a '1' if a line is detected.

Binary to Decimal Conversion: Example 1

• If only L2 detects a line, the binary representation is 1000 (L2 L1 R1 R2).
• Converting binary to decimal involves using powers of 2 based on the position of each digit (from right to left: 2^0, 2^1, 2^2, 2^3).
• For 1000, the calculation is (1 * 2^3) + (0 * 2^2) + (0 * 2^1) + (0 * 2^0) = 8.
• The decimal representation for this scenario is 8.

Binary to Decimal Conversion: Example 2

• If L1 and R1 detect a line, the binary representation is 0110 (L2 L1 R1 R2).
• The conversion is (0 * 2^3) + (1 * 2^2) + (1 * 2^1) + (0 * 2^0) = 0 + 4 + 2 + 0 = 6.
• The decimal representation is 6.

Sensor Combinations and Decimal Values

• There are 16 possible combinations of the four sensors either detecting or not detecting a line resulting in a decimal values from 0 to 15.
• Each combination has a unique decimal value that represents the sensor readings, which the quad RGB sensor module packs into one number.