Sensors

  • VEX Documentation (the links below brings you to the .pdf provided by VEX on the sensor) <click here> to access the VEX sensors page
    • Bumper Switch - The bumper sensor is a physical switch. It tells the robot whether the bumper on the front of the sensor is being pushed in or not. <more info>
    • Limit switch - The limit switch sensor is a physical switch. It can tell the robot whether the sensor’s metal arm is being pushed down or not. <more info>
    • Optical encoder - The optical shaft encoder is used to measure both relative positions of and rotational distance traveled by a shaft. It works by shining light onto the edge of a disk outfitted with evenly spaced slits around the circumference. As the disk spins, light passes through the slits and is blocked by the opaque spaces between the slits. The encoder then detects how many slits have had light shine through, and in which direction the disk is spinning <more info>
    • Line Tracker - A line tracker 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. <more Info>
    • 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 40kHz 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. <more info>
    • Potentiometer - A potentiometer is an electrical device whose resistance is adjustable. The user can therefore adjust the degree to which the potentiometer opposes electric current through it, simply by turning a shaft that is attached to the center of the potentiometer. <more info>
    • Light Sensor -The light sensor enables a robot to detect light. Robots can be programmed to have a specific reaction if a certain amount of light is detected. The light sensor uses a cadmium sulfosolenide (CdS) photoconductive photocell. The CdS photocell is a photo resistor, meaning that its resistance value changes based on the amount of incident light. <more info>
    • Analog Accelerometer -The VEX Accelerometer measures accelerations on three axis simultaneously. By measuring the acceleration of the robot, one can calculate the velocity of the robot, and more importantly the distance this robot has travelled. Accelerometers are also great for detecting collisions and determining if the robot is stopped or moving. <more info>
    • Yaw rate gyro -Use a gyro to enhance autonomous movement and feedback from a VEX robot.Single-axis gyroscopic sensor.Detects a rotation of up to + / - 1000 degrees per second. <more info>
    • Motor 269 Integrated Encoder Module - This product replaces the plastic cap on the back of a 2-Wire Motor 269 with a quadrature encoder. Install this product and connect it to a Cortex Microcontroller via I2C to receive direct feedback from the motor. This encoder provides information on how fast the motor is going, how far it has traveled, and what direction it is moving.ensors can be sensitve to static charges from the field.
    • Setup instructions for IEM
    • Motor 393 Integrated Encoder Module- This product replaces the plastic cap on the back of a VEX 2-Wire Motor 393 with a quadrature encoder. Install this product and connect it to your Cortex Microcontroller via I2C to receive direct feedback from the motor. This encoder provides information on how fast the motor is going, how far it has traveled, and what direction it is moving.
  • Carnegie Mellon Curriculum on sensors - this link brings you to the CMU curriculum on sensors.

                                                                                                                                                        
Line Tracker                                                                                                                          

   

Optical encoder.                                                                       
                                                                                                                                                          













Ultrasonic Range finder                                                                                                                                                                                                                         
 




























Bumper switch

 
...Potentiometer 
Yaw rate gyro

integrated encoder module

Limit switch 

   .Accelerometer



Light Sensor