Transcript Slide 1
Program Light Sensor in Autonomous Mode Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Program Light Sensor in Autonomous Mode Performance Objective: Given the components of a VEX robotics design system program a light sensor in autonomous mode to have the robot travel full speed forward when a lot of light is detected, but to move slowly forward when there is little to no light detected. Enabling Objectives: explain the purpose of a light sensor explain how a light sensor operates draw a flow chart for using a light sensor program a light sensor Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode 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 because of the analog input 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 (The direct light that falls on the surface) Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Verify the sensor Plug the sensor into an analog port Open easyC and download the light sensor test code Move your hand over the light sensor to see the change in value The more light there is, the lower the analog value Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Program the light sensor Program a VEX robot equipped with a light sensor to move forward quickly when there is a lot of light in the room, and move slowly when there is little or no light in the room Draw the flow chart of a program that can complete the above task Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Program the light sensor Open a new competition project and configure the microcontroller for the light sensor Add a variable for the light sensor Insert an appropriate driving mode block into the operator tab Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Program the light sensor Insert a while loop where 1==1 Insert the get light sensor value block Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Program the light sensor Insert an If statement to move the robot forward at full speed if the light sensor value is less than 50, meaning there is a lot of light Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Program the light sensor Insert an Else-If statement to move the robot forward slowly if there is very little to no light in the room Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Test your code Build and download your code Run the code with the Competition Switch Simulator The robot should move forward quickly with the lights on, and move forward slowly when the lights are turned off Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode Show it off! If your code works, show it to your instructor If the robot does not run correctly, go back through the lesson and double check your code For more technical data on the light sensor visit: http://www.vexforum.com/wiki/index.php/Lig ht_Sensor Available at: www.etcurr.com Lesson 3.5 – Program Light Sensor in Autonomous Mode