CE 351 Spring 2022
Homework 5
Name: David Lee
Email: djlee1@fortlewis.edu

PID Control - Photocell

Introduction:
In this homework assignment we learn about PID and how it can control the rate at which something will self correct.

Materials and Methods:
Using Python, Arduino and a bread board we follow the instruments to make reading on the photocell do what we want

Results:

Task 1: Make the light being sensed oscillate around a set point


Figure 1: Shows the light ocsiallting around 800


Figure 2: Shows the code fixed to make it work

Task 2: Save the data and us Python to plot the results from the Sensor using an extra LEd to create extra ambeint light which will make the Main led dim



Figure 3: Shows the Python Graph


Figure 4: Shows the python Code.


Figure 5: Shows the code Used for the Task

This Task used the same code as task 1. However. There was an additional LED connected by a button that would turn on and make the LED connected to pin 3 adjust and go dimmer. That is why we are able to see the self correction the graph produces in Figure 3.



Figure 6: Shows a Video of the Kp set to .001.

The figure above demonstrates how the Kp affect the correction time. The Kp in Figure 3 was Kp=.01 and was able to correct relatively fast. At Kp=0.001 We see almost no correction in a short period of time

Task 3: Save the data and us Python to plot the results from the Sensor which steps the set value and makes the LED adjust to the new Setpoint.


Figure 7: Shows the Python Plot of the Data


Figure 8: Shows the Python code


Figure 9: Shows the Arduino code used for the funciton

Discussion:
This assignment was good to complete. It introduced me to exporting data and made me review my python coding practices. I was able to successfully complete the assignment.