Electronics
The electrical components chosen for the Mystery Machine required balancing cost and performance, all with a focus on integration. See a comprehensive schematic of our electronic systems below, followed by a breakdown of the key components.
Schematic
Motors
For the Mystery Machine, we chose to use 4-12 V Jameco 161382 Motors to drive the wheels. These motors have a 30:1 gear ratio, providing the high amount of torque we desired. Additionally, these motors were found in the "free" bin, so we were able to allocate resources to other robot components. In addition to the 4-12V motors, we used a 5V Servo motor that was rated at 20kg to control our caster wheel attachment. Because of the high torque and its 20kg rating, this motor was perfect for lifting our robot onto two wheels when necessary.
Motor Drivers/H-Bridges
To drive the 4-12V Jameco 161382 motors, we used two L298N motor controllers -- one corresponding to the front wheels and one corresponding to the back wheels. We did not need to use a motor controller for the Servo motor.
Sensors
In order to detect the IR signal sent by the beacons, we decided to use a phototransistor in a transresistive amplifying configuration. This properly amplified the signal and allowed the Mystery Machine to orient flawlessly. After the orientation phase came line detection and line following. The tape sensor we used helped us achieve this task. In addition to the IR and tape sensors, we also implemented a limit switch that would be pressed when the Mystery Machine's front was flush with one of the walls of the playing field. Finally, we used a combination of an on/off switch and a circuit breaker -- for extra safety and to conform to competition rules.
Voltage Regulators
With a focus on integration and a variety of components requiring different voltages, we decided to use two LM317 voltage regulators to achieve varying voltages of ~15V, 12V, and 5V. We were able to achieve a voltage of ~3V directly from the Teensy-LC. This allowed us to power our various components without having to construct our own voltage dividers.