SENSORS RESEARCH
RESEARCH: SENSORS
ULTRASONIC RANGE FINDER
An ultrasonic range finder sensor enables a robot to detect obstacles in its path by utilizing the propagation of high-frequency sound waves. The sensor emits a 40 kHz sound wave, which bounces off a reflective surface and returns to the sensor. Then, using the amount of time it takes for the wave to return to the sensor, the distance to the object can be computed. Unlike the bumper switch and limit switch that alert you when they have been hit, the ultrasonic range finder sensor can alert you to an obstacle in the path of the robot prior to hitting it. This can allow you time to safely navigate around obstacles.
The sensitivity of the sensor depends on the objects’ surfaces that are detected by the emitted sound waves. For example, a reflective surface may produce a different reading than a non-reflective surface.
The resolution of the sensor depends on the sound waves. However, sound waves can reflect or be absorbed and possibly not return with enough power.
The sensor can be used to determine distances to objects. It can be used as a tool to determine if any objects are in the robot’s path at all. To increase the sensing range, the sensor can be mounted to a servo to allow it to rotate. Figure 2 below shows a robot that utilizes such a setup.
LINE FOLLOWER
A line tracker mostly consists of an infrared light sensor and an infrared LED. It functions by illuminating a surface with infrared light; the sensor then picks up the reflected infrared radiation and, based on its intensity, determines the reflectivity of the surface in question. Lightly colored surfaces will reflect more light than dark surfaces; therefore, lightly colored surfaces will appear brighter to the sensor. This allows the sensor to detect a dark line on a pale surface, or a pale line on a dark surface. The line tracker allows your robot to follow a pre-marked path and allows humans to indirectly control the robot while it is autonomous.
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ULTRASONIC RANGE FINDER
An ultrasonic range finder sensor enables a robot to detect obstacles in its path by utilizing the propagation of high-frequency sound waves. The sensor emits a 40 kHz sound wave, which bounces off a reflective surface and returns to the sensor. Then, using the amount of time it takes for the wave to return to the sensor, the distance to the object can be computed. Unlike the bumper switch and limit switch that alert you when they have been hit, the ultrasonic range finder sensor can alert you to an obstacle in the path of the robot prior to hitting it. This can allow you time to safely navigate around obstacles.
The sensitivity of the sensor depends on the objects’ surfaces that are detected by the emitted sound waves. For example, a reflective surface may produce a different reading than a non-reflective surface.
The resolution of the sensor depends on the sound waves. However, sound waves can reflect or be absorbed and possibly not return with enough power.
The sensor can be used to determine distances to objects. It can be used as a tool to determine if any objects are in the robot’s path at all. To increase the sensing range, the sensor can be mounted to a servo to allow it to rotate. Figure 2 below shows a robot that utilizes such a setup.
LINE FOLLOWER
A line tracker mostly consists of an infrared light sensor and an infrared LED. It functions by illuminating a surface with infrared light; the sensor then picks up the reflected infrared radiation and, based on its intensity, determines the reflectivity of the surface in question. Lightly colored surfaces will reflect more light than dark surfaces; therefore, lightly colored surfaces will appear brighter to the sensor. This allows the sensor to detect a dark line on a pale surface, or a pale line on a dark surface. The line tracker allows your robot to follow a pre-marked path and allows humans to indirectly control the robot while it is autonomous.
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