Embedded Files
NORMAN's hardware includes a three-floored chassis, a coal-collecting crate and paddle, a coal-dumping arm, a game start flag, Neopixels, and a 2-wheeled drivetrain with caster wheels.
Crate
Crate
The crate features an inclined floor and roof to encourage coal in and out of its opening. A micro Servo actuates a paddle that pushes coal into the crate, one by one.
Exploded View
Exploded View
Arm
Arm
The dumping arm is fastened to the crate and driven by a continuous DS Servo. When actuated, the arm rotates 180 degrees from its starting position, leveraging gravity and the crate's inclined roof to drop coal into a bucket.
The dumping arm is fastened to the crate and driven by a continuous DS Servo. When actuated, the arm rotates 180 degrees from its starting position, leveraging gravity and the crate's inclined roof to drop coal into a bucket.
To ensure that our servo was capable of lifting an entire crate of coal, we performed a quick back-of-the-envelope analysis. In the worst case, the servo motor stalls and provides its maximum (stall) torque.
Calculations
Calculations
By calculating maximum expected loads using statics equations, we were able to spec an appropriate servo motor to lift the crate while ensuring the motor would not stall. The following spreadsheet allowed us to quickly test different lengths and masses to ensure we had a reasonable factor of safety on the maximum required torque.
Game Indicators
Game Indicators
NORMAN's Neopixels turn green at the start of the game, indicating the start of the 2 minute and 18 second countdown. Once time is up, the Neopixels turn red.
Once NORMAN detects which arena it is in, it flips a flagpole to wave either the blue or green flag.
Balloon Assembly
Drivetrain
Drivetrain
The drivetrain consists of two DC motor-driven wheels accompanied with encoder magnets for position control. The assembly is supported by flanged bearings and alignment mounts to reduce cantilever bending of the drive shafts.
Exploded View
Chassis
Chassis
The chassis consists of 3 floors.
The bottom floor houses:
2x 7V batteries
Drivetrain subassembly
2x Caster Wheels
5 IR Line Sensors
PIC32 Leader and Follower
2x Motor Driver
2x Crate "Wiggle-Stoppers"
The second floor holds:
Beacon Detecting Circuit
Power Distribution Board (PDB)
The top floor, or "crow's nest", holds:
Game Starting Flag
Arm Pivot Subassembly
Neopixels
The chassis floors are attached via standoffs including the N-shaped stands between second and third floors, giving NORMAN its name.
Mechanical Bill of Materials
Mechanical Bill of Materials
Total Mechanical Hardware Cost: $16.42
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