Objective
----Comments on output?
What range of values did your potentiometer output?
Did Turning your potentiometer clockwise increase or decrease the value?----
The value of the Potentiometer ranged from 0 to 100. Turning clockwise decreases the value returned by the potentiometer, and turning counter clockwise increases the value.
----What range of values did your photo resistors output for a white surface and for a black surface?----
For black surfaces the level was close to 0 and for white surfaces it fluctuated around 500, and somehow one of the photoresistors was picking up values over 1000. This might be because they still need calibration or the lighting was different.
----Explain what you have created, what functional modifications (need at least 2)
you made to the design and add a picture of your 3D printed chassis----
We integrated photoresistors in a protoboard instead of a bredboard because it is more organized and compact. The SPID controls were also attached to this protoboard, and the protoboard itself is attached to the chasis by hot glue. The light shield is made from cardboard pieces attached by hot glue and tape, it also includes LEDs to make photoresistor reading accurate.
----What is the purpose of the motor driver/shield?----
The motor driver defines the movement of the wheels depending on the reading of the photoresistor, it allows the robot to move by following a line.
The shield blocks unwanted light that makes the photoresistor reading inaccurate.
Challenge #7: Explain why you need to calibrate your photoresistor values.
What problem does this help solve and what problems do you still see coming from your photoresistors?
1. We needed to calibrate our photoresistor because they need to be adjusted so they can return changes in light level, which signifies when there are turns in the line.
2. Calibration helps us solve problems like inaccuracies in light reading and movement. Some errors we might expect are robot movements making the photoresistors bend out of place and LED brightness affecting photoresistor reading.
Significant Changes:
For our chasis significant changes, we modified and printed a new chasis that has square holes fit to attach 3d printed walls, which we use to divide the components of our robot in three parts:
1. Components (Holds photoresistors and Potentiometer)
2. Supply (Holds the Motor Battery Pack)
3. Control (Holds the Arduino and its battery)
----What was the best PID values that you used? How well did this track? Any limitations?----
Based on testing, we found that some of our PID values had to remain fixed, like speed and kP. This is because these are the more significant values that affect how fast the robot moves and responds to light level changes. Some limitations include a decrease in efficiency due to lower speed and constant need of changing values for different maps.
----What does PID stand for? What is the purpose of the P, the I, and the D?
What steps did you take to choose the best values for your robot?
Explain this like you would for someone taking this course next year.----
P - Proportional: This takes the current error value and corrects it by comparing it to proportional gain & output a desired turn rate.
I - Integral Control: This sums past errors and keeps it in memory in order to prevent the growth of errors that may impact turn rate over time.
D - Derivative Control: This predicts the increase/decrease in error and prepare accordingly in advance.
To find the ideal SPID values, we used extensive testing of different settings and by observing how each value impacts the performance of the robot we found constantly functional settings.
Video 1: Line following Test
Video 2: Competition - Drag Race