ME218B 10-11 Project: "Hoops"

"Hoops" Project

Capstone Project for ME218B 10-11

• Concept, System, Mechanical, Electrical, and Software Design
• Still Ongoing!

IMPLEMENTATION

Mechanical Design

Evolution of Iris Design: Final Version

Final Mechanical Design

System Design

Key Learnings and Design Points

• Servo Actuation Linkage Incorporated
• Retaining Cage Constrains Concentricity

Rationale

Evolution of Iris Design: Second Iteration

Key Learnings and Design Points

• Tab-Slot Design - Easy to Assemble/Disassemble
• Intersecting Planes Make Structure Very Stiff, Robust
• Infrared Beacon For Navigation of Robots

GOAL:

Allow students to gain experience designing and integrating an intelligent, mobile machine by creating a GAME in which their machine will compete.

GAME:

An evolution of one-on-one BASKETBALL, with DYNAMIC HOOPS, commandable BALL DISPENSERS, and a remote GAME MASTER.

Key Learnings and Design Points

TASK:

• Much Better Actuaton Travel
• Leaves not Cantilevered, Support Each Other
• No Physical Concentricity Constraint
• No Gaps!

Careful Layout

To Minimize

Wasted Material

When

Laser Cutting

Physical Prototype Laser Ccut

and Assembled

Create the electro-mechanical and software INFRASTRUCTURE for this game. It should be robust, entertaining, ready in 6 weeks, and cost < $200!

Evolution of Iris Design: First Iteration

Dynamic Hoop Realized

Key Learnings and Design Points

System Design Overview

• Does Generate Iris Diaphragm Effect
• Not Much Actuation Travel
• Gaps in Iris when closed
• Weak, Cantilevered Leaves

Concept:

Key Learnings and Design Points

• PC-Based Game Master for managing overall game functionality.

• Distributed Infrastructure Nodes (Hoops/Dispensers) for Actuating and Sensing Game Field.

• Distributed OC (Offensive Coordinator) Nodes to allow students' Robots to communicate with Game Master

• Wireless Communication based on standard protocol between all nodes.

A Dynamic Basketball Hoop

• It Works!
• Netting Used to Capture Balls, and Convey through Break-Beam for Scoring
• VERY Robust

Dispenser Specs

Hoop Specs

What if the Rim Diameter of a Basketball Hoop Could Dynamically Change?

• Smaller Diameter = Basket Worth More Points
• Iris Diaphragm-Based Design
• Inspired by Camera Apetures, Countless Science Fiction Movies, etc.

Field Specs

Game Master Graphical User Interface

Currently Under Development...

Concept:

Flexible, Wireless, Microcontroller-based

PCB for Hoops and Ball Dispensers

Software Overview

Microchip PIC16F690 8-bit Microcontroller, 20-Pin, 10MHz,

256 bytes RAM, 7k FLASH, nanoWatt Technology, $2.44 Each from Digikey

Hoop/Dispenser

Software Module Breakdown

XBEE from Digi, 2.4GHz, 801.15.4 ZIGBEE

RF Radio, ~30m Range,Very Low Power,

$19.00 Each from Digikey

MAIN

XBeaconBoard Schematic

ISR

Initialization

Module

Microcontroller Pinout and Peripherals

Hoops/Dispensers:

ANSI C

Game Master: Tcl/Tk

SPItoLED

Module

LED Control

Module

XBEE MODULE

XBeaconBoard

Microchip MPLAB IDE v8.63

HITECH C LITE Compiler v9.81

Freely available from Microchip

ActiveTcl Tcl Distribution

w/ Tk GUI Toolkit

Tcl: "Tool Command Language"

Open-Source Scripting Language

Heartbeat/Low Battery Module

Break Beam Module

PWM Module

No Prior Knowledge of Tcl/Tk...

Robustness and Abstraction

Key Learnings and Design Points

I/O Block Detail...

Software

Development Tools

• PIC16F690 8-bit Microcontroller, 10 MHz, 20-Pin DIP
• XBee-based ZIGBEE 802.15.4 Wireless Communication
• Interrupt-Controlled, Constant-Current Infrared LEDs for Navigation
• Break-Beam Sensor Circuit, Low Battery Voltage Detect
• 7x I/O Blocks, Customizable Depending on Population

My own PIC16F690 Dev Board

In-Circuit Serial

Programming Header

3 Debug

LEDs

Configurable for Low-Side Drive Output with Logic Level or Power N-Channel MOSFETS, Optional Series Resistance, Direct Output Drive from Port, Direct Input to Port.

Readily adaptable for motors, LEDs, sensors, servos, etc.

3 Debug

Buttons

On-Board +5V

Low-Dropout

Voltage

Regulator

RS-232 Level Shifter for

Serial Communication with PC

RJ-11 Phone

Jack to Connect

to PC, Debug with

Terminal

XBeaconBoard

PCB Design

First PCB I ever designed!

Microchip

PICkit 3 Programmer

PCB Layout

XBee Radio

Socket

Microcontroller

"Bus Pirate" for

Synchronous and Asynchronous

Serial Sniffing and Debugging

RESULT: Rapid Software Development

XBeaconBoard PCBs

Fabricated and Assembled

I/O Blocks,

Overlapping

Footprints

Rendering of Board

Constant-Current

Driverand IR LEDs

Assembled for Ball Dispenser

Key Learnings and Design Points

Break-Beam

Configured

To Count

Scored Points

Break-Beam

Configured

To Stop Motor

After One Ball

Dispensed

• Board Size: 2" x 3"
• Powered by 4x "AA" Cells
• Board Design is Flexible for Future Projects

Software Design

Remaining

I/O Blocks

Configured to

Control LEDs

(Low-Side Drive

w/ N-Channel

Logic Level

MOSFET

Outputs)

I/O Block

Configured

To Control Iris

Servo

(Direct Output

from Port)

Assembled for Hoop

Key Learnings and Design Points

I/O Block Configured

To Control Ball Dispenser

Magazine DC Brushed Motor

(Low-Side Drive w/ N-Channel Power MOSFET Output)

• +3.3v Regulator Footprint Reversed in Design
• Omitted Traces Identifying Board Edge
• One I/O Block Connected to Input-Only Port

Electrical Design

Current State of Project