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Athletic Field Marking DeviceAnthony Cortese, Ryan Crump, Matthew Lawler, Patrick Shaughnessy (Team Leader), John Sudia
Project Objective
• To create a semi-automatic device that provides a means of lining an athletic field.
Solution Requirements
• Must accurately paint a straight line between two determined points
• Must have the capability to make error corrections on its own.
• Must operate with as little human interaction as possible
System Goals• The device should be able to complete a line 120
yards long
• The device should require less long term costs than current methods
• The device should require less human labor than current methods
• The device should complete its tasks in a reasonable amount of time
Major Challenges
•Dealing with the accuracy of all of the components in our machine
•Creating a drive system that can correct itself when deviating from the desired path
•Keeping the expense of the product to a minimum
•Working in a multi-disciplinary team atmosphere
Potential Guidance Solutions• Differential RTK GPS
• High accuracy GPS, ranging from 10cm to 1cm• High cost and complex implementation
• Laser Optical Guidance• Utilizes laser scanners which give out X and Y
coordinates and heading • High accuracy but cost prohibitive
• Infrared Sensor• Reflective infrared sensor• Cheap and easy to implement
Potential Drive System Solutions
• Gas Powered Engine• Heavy vibration• Weight issues• Complex integration
• Electric Motor• Cheap and readily available• Easy to control• Simple integration
Potential Paint Delivery Solutions• Compressed Tank
• A compressed tank • Paint modulation control• Spray nozzle• Complex and expensive
• Aerosol Spray Can• Inverted spray can• Solenoid to trigger it• Simple and low cost
Guidance System Solution
• An infrared sensor retrieves location data
• Microcontroller receives and processes data from sensor
• Motor controller receives instructions from the microcontroller and outputs voltage to motors
Guidance: Infrared Sensor
• The Lynxmotion board consists of three reflective infrared sensors
• Our system uses the outermost sensors to determine its location relative to the target line
• These sensors each relay either a ‘0’ or ‘1’ for absence or presence of a line
Guidance: The Handy Cricket
• The Handy Cricket microcontroller processes the digital output received from the sensor
• Based on input, the microcontroller determines device location relative to line
• The microcontroller determines appropriate correction necessary and transmits data to motor controllers
Code Block Diagram
Left sens = 0
Start
Input left sensor
Input right sensor
Right sens = 0
Stop
Input rightsensor
Right sens = 0 No change
Increase rightMotor speed
Increase leftMotor speed
Y
Y
Y
N
N
N
Guidance: Motor Controller
• The motor controller can precisely control the speed and acceleration of the motors for easy path correction
Electrical Schematic
+
-
12
VSolenoid
+ -
12 V
IRSensor
MM
C+-
Microcontroller
MM
C+- +
-
12
V
Digital I/O5V
+ -
+-Signal+-Signal
IRSensor
Serial bus
Sensor input
5V
5V
Relay
Drive System Solution
• Each side is independently powered by a separate DC motor
• That DC motor drives a sprocket connected to its side’s drive train
• That drive train is responsible for transferring power to both wheels
Drive System: Motors
• The motors are ¼ HP, 180 RPM and require a 12 volt/3 amp power supply
• Max torque and lower speeds needed for our application
• 2:1 gear ratio was selected to give more torque and a lower speed
Drive System: Gear Ratio• To achieve our gear ratio, the motor turns a 12 tooth sprocket
which is attached by a chain to a 24 tooth sprocket on the rear axle
Drive System: Drive Train
• The rear axle has an additional sprocket which connects to another sprocket on the front axle in a 1:1 ratio by a chain
• Each axle is supported by two ball bearing mounts attached to the frame
• The 8” diameter wheels are locked onto the axles by a custom wheel mount
Paint Delivery Solution• The paint delivery system consists of a linear pull solenoid, trigger and spray paint can
• The solenoid will pull a trigger which will dispense paint from the can
• When it is necessary to halt painting the solenoid will release the trigger ceasing the paint flow
• Width of line is adjustable
Cost AnalysisThe Handy Cricket: $99.00 ;Prof. Dougherty
Lynxmotion Sensor: $32.00
Gamoto Motor Controller: $99.00 x2 = $198.00
Solenoid: $10.00
Wheels: $8.69 x4 = $34.76
Bearings: $4.64 x8 = $37.12
Sprockets: $22.33
Chains: $21.94 ;Battlebot
Aluminum Frame: $114.00 ;Projects Room
Motors: $85.00 x2 = $170.00 ;Battlebot
Miscellaneous: $20.00
----------
TOTAL: $759.15
Existing Methods: >$1000.00
Conclusion
• While we have not yet completed our project, we have learned some important lessons
• We still view our initial goals as attainable and anticipate reaching them upon conclusion
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