By: Tai Nguyen (E&C Engineer)
Verified By: Ernie Trujillo (Project Manager)
Approved By: Miguel Garcia (Quality Assurance)
Introduction:
Infrared sensors work by using an LED to emit infrared light and then having a sensor that measures the intensity of the reflected light. When an object is close to the sensor, the intensity of the reflected light will be greater. Light intensity also depends on the material and color of the object the LED is shining on. Lighter colors will tend to reflect more IR light while darker colors will tend to absorb IR light, thereby reducing the amount of light reflected.
QRE113 Analog IR Sensor
- 5V DC operating voltage
- 25mA supply current
- Analog I/O
- Optimal sensing distance: 3mm
- Cost: $2.95
Pros of using and IR Sensor:
- Very easy to learn and use
- Can differentiate between white and black which allows for line following
- Maze already created and printed
- 3DoT board already has pins allocated for an IR sensor shield
- Runs on 5V DC so power won’t be an issue
- Small, takes up little space
Cons of using IR Sensor:
- Tall robots will need to find a way to keep sensors lower to the ground for optimal sensing (3mm)
- Already been done before, therefore not as impressive as other options
- Requires the maze to have a grid and forces robots to line follow
- Grid on a maze looks crowded
- Most colors cannot be used as the IR sensor cannot differentiate between the different colors, EX: Green can return the same value as black
Conclusion:
IR Sensors are a great start for projects as the basics of design and coding can be easily taught through using them. Line following has been done by many colleges and projects, so there are plenty of resources to assist many beginners. If robots use IR sensors to navigate through a maze, the maze would be required to have lines in the middle of pathways for robots to follow. While IR sensors are relatively easy to use, the sophistication of projects goes down and will not seem as impressive to most companies who look to hire quality electrical engineers.
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