Hardware
Squeaky is a relatively big bot, measuring 11’’x12’’x7.5’’. His features include a chute with a 21-ball capacity, a gate on the chute for dumping balls, a gearbox-turning tire mounted vertically on its left side, a lever-pulling lever arm seated front and center, two pairs of back wheels on each side, and one mini caster wheel in the front.
While initially, each of these components were built separately and then attached onto the chassis, we soon learned that this method of building created a weak robot that would constantly have parts popping off. As a result, later iterations of Squeaky used the supports of one component as the base for another, interconnecting all Squeaky's parts, and thus allowing for a stronger bot.
Specs
Chute:
- Gravity operated
- 8 degree slant
- 21 ball capacity
Gate:
- Servo operated
- conveyor-belt connection to servo
- 180 degree rotation
Gear-turning tire:
- DC motor operated
- 125:1 gear ratio
- vertically mounted
Lever-Arm:
- Servo operated
- 90 degree rotation
Wheels:
- Caster wheel in front
- Motor driven rear wheels
- 125:1 gear ratio
- Differential steering
Sensors
- Mounted on the front
- Used for alignment when pulling lever
Gyroscope:
- Housed near the motor block
- Provides low latency heading information
IR LED & Phototransistor:
- Mounted on either side of the front of the chute
- Used to check if chute is filled to capacity
Powertrain
The motors are held securely in the center of Squeaky using a lot of vertical braces and supporting beams. They are connected to the wheels through a series of gears that result in a 125:1 gear ratio, making the wheels move slower but with higher torque. Initially, the axles of two of gears were not supported on both sides. As a result, these gears were not stable and our robot squeaked every time it accelerated. Hence, the name Squeaky was born!