An exploration was performed to investigate the usefulness of different sensors on the robot. Two of these sensors that were explored were the CdS cell sensor and a micro bump-switch. They were used to both control other motors connected to the proteus and to assist with navigation.
Determining Light Color
A CdS cell was connected to the robot to read in light intensity value. The robot was placed over multiple different surfaces to determine the value returned by the CdS cell when it reacted to different colors or reflectivities. To test this, the cell was powered and its return values were written to the proteus screen. Doing this, it was discovered that a red light would yield a value of ~0.450 and a blue light would yield a value of ~0.900. This allowed the robot to know when a certain light was detected, which would assist with starting on the start light and with pressing the correct diagnostic button. This portion of the exploration had a significant impact on the final design of the robot. A CdS cell was attached to the bottom-middle of the chassis to read the color of lights below the chassis. This was used to detect the starting light, which was always red, and it was used to determine the color of the diagnostic light. The design of the chassis was such that external light was blocked out from the bottom. This acted as a sort of cone for the CdS cell, allowing the light it read to be pure. This eliminated the need to put a cone around the cell, and made it so a filter was not as impactful to our robot.
Controlling a Servo with a CdS cell
Using the knowledge from the first part of the exploration, code was written to adjust the degree of a servo motor based on the intensity of the light returned by the CdS cell value. This allowed the robot to adjust certain components of its task completion mechanisms based on its environment. However, this specific implementation did not make it into the final design of the robot. The only separate component of the robot that the CdS cell affected during the run was the direction in which the motors turned to press the correct diagnostic button. The CdS cell values never affected the motion of a servo.
Navigation with MicroSwitches
Microswitches were affixed to the robot to explore a new method of navigation using microswitches. Code was written for the robot to navigate a certain course using only bump switches. This way, the robot knew when it would hit a wall, and then would turn accordingly. This was very helpful for navigating regarding only 90-degree angles and turns. The robot was able to navigate the course accurately. However, the use of bump-switches did not make it to the final design of the robot. The robot mainly relied on sleep-based movements and RPS for navigation.