Grassinator1300Senior Design

Mid-Semester Design Presentation 2014

Julie White (Team Leader)• Website• Sensors• Autonomous Implementation

Glen Luker• Remote Control Implementation• Autonomous Implementation• Hardware Implementation

Grassinator1300 Team

Grassinator1300 Team

Aaron Ray• Power System Design• Electrical Subsystem

Testing• CAD Design

Perry Clark• Hardware Implementation• Hardware Components

Testing• Hardware Debugging

Timothy Mange• Lead Documentation• Electrical Subsystem Design• Power System Testing

Faculty Advisor

Dr. Raymond Winton

Overview

• System Overview• Problem and Solution• Technical and Practical Constraints• Changes and Refinements• Packaging• Test Plan• Future Goals

System Overview

Power System Microcontroller

Drive System

SensorsRemote Control

Problem and Solution

Problem

Current lawn mowers require prolonged physical labor and sun exposure.

Riding mowers can create additional cleanup work because of their size.

Push mowers do not create cleanup work but still require physical work and sun exposure.

Combine the usability of a riding mower with the size of a push mower, while further reducing the sun

exposure with autonomous features.

Solution

The Grassinator1300 intends to solve these problems by providing a small gas-powered push mower platform that is radio-controlled (RC).

• Use RC mode to record and execute movements

• Operate in autonomous mode

• Allow user to supervise from a nearby shady area

• Limited physical labor.

Solution

Technical and Practical Constraints

Name Description

Battery Requirements The Grassinator1300 must be powered by a 24 VDC battery supply.

Obstacle Detection Obstacles must be detected at a minimum of 6-inch range.

Remote Control The remote control must be able to communicate with transmitter up to 150 feet without any obstructions.

Cutting Height The Grassinator1300 must have an adjustable cutting height between 1-2.5 inches.

Speed/Servos The Grassinator1300 must be able to maintain a speed of about 3 MPH.

Technical Constraints

Proper safety measures and shut off features should be implemented to keep people and animals safe.

System will shutoff if:

• Microprocessor malfunctions

• Motor stops working

• Sensor fails

Practical Constraints

Health & Safety

The Grassinator1300 will not be designed to work in stormy or inclement weather.

Practical Constraints

Environmental

[1]

Changes and Refinements

Kill Switch

• Allows the microcontroller to control the blade motor• PCB Relay Circuit (original design)

• Arduino could not supply enough current to activate.• Time delay too large if power was lost.

• Relay Module(new)• Integrated circuit• Arduino compatible

[2]

Battery Monitor

• Allows user to actively monitor the battery level.• Voltage divider maps voltage into safe range.• Keeps device from becoming unstable.

[3]

SD Card Reader• EEPROM onboard Arduino (Original)

• Limited memory• Expensive• Stored directly in memory

• SD card reader (New)• Interchangeable memory cards• Inexpensive• Stored as a character in a file [4]

Arduino Uno to Arduino Mega

• Added features require more digital I/O pins• Mega: 54 digital I/O pins• Uno: 14 digital I/O pins

• Minimum code change requirements.

[5]

Packaging

Schematic

Schematic

Schematic

Schematic

PCB3

inch

es3.85 inches

PCB Enclosure

Packaging

Test Plan

PROJECTED TIMELINEDescription Date

Order PCB ASAP

PCB Trace Testing 3-28

PCB Population 3-31

Overall System Test 4-4

Projected Timeline

Test Plans part 1

• The PCB will be trace tested and populated within a week of arrival from manufacturer

• Then PCB will be powered and checked for expected voltages

• Subsystems will then be tested using the PCB to ensure functionality

Test Plans part 2

• Subsystems will be secured inside enclosure and constraints testing will begin on overall system.

• Field testing of entire system.

• Retesting of any corrections made due to failed tests.

Jan. Feb. March

April May

PCB Design

Prototype Refinement

PCB Population/ Packaging

Testing & Debugging

Future Goals

[1] “How to Mow Now That it has Stopped Raining”, Purdue, Accessed: Sept . 28, 2013 http://purdueturftips.blogspot.com/2013/04/how-to-mow-now-that-it-has-stopped.html

[2] “Relay Module (Arduino compatible)”, DFRobot, Accessed: March 3, 2014 http://www.dfrobot.com/index.php?route=product/product&product_id=64#.UxUdt_ldXni

[3] “How Well Do Ipad Batteries Compare to Other Tablets? Ipads Smoke the Competition”, Iphone Hacks, Accessed: March 3, 2014

http://www.iphonehacks.com/2012/12/ipad-battery-comparisons.html

[4] “SD Card Reading Writing Module for Arduino”, DX, Accessed: March 3, 2014 http://dx.com/p/sd-card-reading-writing-module-for-arduino-deep-blue-142121

[5] “Arduino Mega 2560”, Arduino, Accessed: March 3, 2014

http://arduino.cc/en/Main/arduinoBoardMega2560#.UxUhGvldXng

References

Grassinator1300Senior Design

Mid-Semester Design Presentation 2014