EGR 3380 Junior Design
Fall 2003
Design Project Description
Title: Ping Pong Jousting
Design Process Overview:
This project description, which includes initial project needs/specifications, has been developed by the course instructors, hereinafter to be called “the clients”. In response to this project description, student teams, hereinafter called “design teams”, will design, document, construct, and implement an electromechanical device to satisfy the below needs/specifications and any official amendments thereto. The project will require milestones to be met as specified in the course calendar, and elaborated upon in class. These milestones will include, at various times, written reports, design drawings, oral presentations, and hardware demonstrations. In all phases of the design process, design teams shall strictly adhere to all guidelines relating to laboratory and shop safety, academic honesty, and ethical conduct.
Design Problem Overview:
Ping Pong Jousting is a head-to-head contest that takes place on a playing field, the geometry of which is specified in the accompanying drawings. Briefly, the playing field consists of two halves of a 2’x3’x8” rectangular plywood enclosure separated by a partition running down the middle in the long dimension. The partition contains 10 holes equally spaced between the ends. Ten ping pong balls will be initially set in the holes, one to each. Four of the balls will be worth (+2) points each (these are dark colored in the drawing), while the remaining six will be worth (-1) point each (light colored), and the ordering of the different valued balls will be as shown.
Two teams will position their devices in starting areas on opposite sides and ends of the wall. On a start command, each team will activate its device via an electrical switch. No further human interaction is allowed during the match.
After initiation, the devices will attempt to score points for their teams either by moving negatively-valued balls into their opponent’s half of the field, or by extracting positively-valued ball into their own half. Action will continue until all ping pong balls are knocked out of their holes, or until one minute has elapsed, whichever comes first. After the match ends, the values of the ping pong balls on each side of the wall are totaled and the team with the greater total value on its side of the wall is the winner.
Project Needs/Specifications:
• Jousting Chamber: Defined as shown
in the attached drawings. The chamber will be constructed of ½ inch plywood
for the base and frame, 2”x4” and 2”x8” lumber for the wall and starting blocks,
and clear plastic for the cover. One of more jousting chambers will be provided
by the clients for use in common by all design teams.
• Ping pong balls: Standard size and weight, having nominally a 1.5” diameter.
Balls will be provided by the instructors for competition purposes. Teams must
supply their own ping pong balls for testing and practice purposes.
• Power: The device may use electric power (battery and/or standard 120 V AC
wall outlets) and/or mechanical power (springs, compressed air, and/or raised
weights). Any power source with potentially hazardous energy content (particularly
AC electric or compressed air) must be handled in a safe manner, following all
applicable codes and guidelines for component sizing, insulation, shielding,
etc.
• Starting Position: Prior to device initiation, no part of the device may extend
into the chamber beyond the starting plane. The starting plane is a plane which
is coincident with the inner end of the starting block.
• Device Initiation and Operation: The device must be activated by one electrical
switching action. After initiation, no further input is allowed from the operator
until such time as the contest official declares the match concluded, at which
time the operator may deactivate the device.
The goal of the team is to have
a greater point score than the opposing team. A team gains points when positively-valued
balls are moved to its side of the chamber. The opposing team loses points when
negatively-valued balls are moved to the opponent’s side of the chamber. After
activation, the device, or any part thereof, may move anywhere inside of its
half of the jousting chamber in order to accomplish these objectives.
• Ball and Chamber Integrity: Permanent damage to any ball or any part of the
jousting chamber caused by a design team’s device during operation will result
in disqualification of the team.
• Noninterference Rule: If any part of a design team’s device, or if any material
propelled by a team’s device (other than the ping pong balls), obstructs, damages,
or otherwise impedes the operation of the opposing team’s device during operation,
the offending team will be disqualified.
• Safety: The device shall not present an undue hazard to persons or property.
Appropriate safeguards and/or labeling should be in place (for example, for
electrical components, pinch points, rotating parts, etc.). All fabrication
required for the development of the system will be conducted with proper adherence
to the general safety guidelines in place for the Engineering Department laboratories
and workshops. In addition, specific safety measures will be followed for each
tool used in the fabrication process. Negligence and/or indifference in meeting
these requirements, or in reporting violations thereof, are grounds for failure
of this course.
Design Project Specifications – Addendum 1 – 10/8/2003
• Clarification regarding what parts
of the device can extend outside of the opening in the jousting chamber:
o Context: Clearly, in order to use A/C electrical power and/or compressed air,
at a minimum, a power cord and/or air hose must enter the jousting chamber from
the outside.
o Question: Given that something is allowed to extend outside of the chamber
initially, what are the limits upon the parts of the device which may do so?
For example, may an electrical transformer, air valve, or some other part of
the device rest outside the chamber.
o Intent: The intent of the client was that no part of the device should rest
upon the table outside of the chamber; i.e., the device must be fully supported
on the bed of the chamber.
o Clarification: Any part of the device may extend out of the chamber so long
as it is fully supported on a platform which is in turn fully supported upon
the bed, wall, or lip of the chamber, and which is attached to the chamber in
a non-permanent way. One power cord and/or one air hose may extend from such
a platform to connect with external power sources.
• Air pressure is limited to 50 psi.
o All safety guidelines must be followed with respect to use of compressed air.
o All air components (hoses, fittings, valves) must be rated for the pressure
being used.