Purdue ECE Senior Design Semester Report

Course Number and Title / ECE 477 Digital Systems Senior Design Project
Semester / Year / Spring 2010
Advisors / Prof. Pai and Dr. Johnson
Team Number / 10
Project Title / RAPTORS
Senior Design Students – Team Composition

Name

/ Major / Area(s) of Expertise Utilized in Project / Expected Graduation Date
Jeff Kubascik / EE / RF, System Design / May 2010
Joe Trefilek / EE / Sys. Design / May 2010
Paul Scheffler / EE / Sys. Design, Emb. Sys. / May 2010
Matt Rockey / CmpE / Software / December 2010

Project Description: Provide a brief (two or more page) technical description of the design project, as outlined below:

(a)  Summary of the project, including customer, purpose, specifications, and a summary of the approach.

RAPTORS is an remote aerial vehicle designed for data aggregation. It is designed for the RC Airplane enthusiast who also possesses an amateur radio license and wants to expand the capabilities of their plane. Equipped with a camera, navigational sensors, and a theoretical 10 mile flight radius, RAPTORS has the full ability to be flown out of the user’s sight, though FCC regulations prohibit this activity.

(b)  Description of how the project built upon the knowledge and skills acquired in earlier ECE coursework.

ECE 270 and 362 introduced project-critical knowledge about digital and embedded system design. Along those same lines, ECE 264 provided basic C skills that were helpful in programming the microcontroller. ECE 201, 202 and 255 all introduced basic circuit design concepts that were crucial in the creation of various on-board systems incorporated into RAPTORS. ECE 382, control systems analysis, was used in the command of the aircrafts control surfaces. ECE 440, 301 and 302 provided valuable background information for the conception and analysis of the RF transmission system. Finally, ECE 321, 323, 423, all motors classes, were helpful in the selection of motor and control mechanisms.

(c)  Description of what new technical knowledge and skills, if any, were acquired in doing the project.

Collectively, the Team RAPTORS members gained experience in several different fields throughout the process of design and construction. Some of these include embedded systems design and programming, C# programming, RF and amplifier design, PCB design and manufacturing processes, system design with respect to packaging constraints, intelligent component selection, amateur radio licensing processes and regulations, and RC plane navigation.

(d)  Description of how the engineering design process was incorporated into the project. Reference must be made to the following fundamental steps of the design process: establishment of objectives and criteria, analysis, synthesis, construction, testing, and evaluation.

As a project, RAPTORS inherently led itself to the formulation of strict objectives and criterion. Establishment of objectives was fairly straightforward, as we wanted to create a data collection system that could be contained inside an RC plane; this gave us size, power, and weight constraints. Analysis of the criteria led to specific decisions about component selection and system design; for example, the modularity of the project as necessitated by space and operational requirements. The modularity of the project also dictated how we approached synthesis by creating two separate modules. Construction and testing were simplified by the modularity of the design and the parity of the identical modem modules. The early establishment of clear objectives naturally led to the evaluation of our project with respect to aforementioned objectives.

(e)  Summary of how realistic design constraints were incorporated into the project (consideration of most of the following is required: economic, environmental, ethical, health & safety, social, political, sustainability, and manufacturability constraints).

Economic: We were able to subsidize some of the cost of the project by requesting samples of the microcontroller from the manufacturer. However, many of the other components of the project were prohibitively expensive, such as the plane, the sensors and the servo and motor set. Since the relatively small amateur radio and RC plane markets are already filled with expensive luxury products, the RAPTORS system would not be out of the norm.

Environmental: Most of the environmental impact of RAPTORS stems from the use of a potentially environmentally harmful LiPo battery to power the plane and the use of leaded solder when attaching discrete parts to the PCB. The environmental impact could be reduced by using lead-free solder along with RoHS compliant parts. The battery, however, cannot be feasibly replaced by a more environmentally friendly power source; as such, proper disposal of the battery at the end of its lifetime is critical to reducing environmental impact.

Ethical: The ethical concerns associated with RAPTORS are only a problem when the vehicle is used in an improper manner. Operation by a person not possessing an amateur radio license, flying the vehicle out of the user’s sight, and using the plane to drop, shoot, or transport illegal materials are all against federal regulation. In addition, using the camera to surveil others without their knowledge or consent is a serious breach of ethics. All these are issues beyond the control of the designers, and violate the product’s intended use.

Health & Safety: There are inherent safety issues that accompany the implementation and usage of RAPTORS. Loss of control, through dropped wireless signal or microcontroller failure, has the potential to cause serious human injury through plane-person collision. In addition, power system malfunction could be a fire and/or shock risk. Minimizing these risks include designing fail-safe systems that shut down the power system on failure, and a system that returns control to a back up control system on loss of signal. Injury due to misconduct cannot be mitigated however; a loss of appendages due to the high speed propeller is a serious risk if RAPTORS is not handled properly.

Political: The RAPTORS vehicle has the potential to cause serious political repercussions, as does any unmanned aerial vehicle. Usage by governments to surveil the military or non-military operations of other countries could have serious political backlash, as demonstrated by past occurrences of said event. Since RAPTORS is also available to private parties, it can be used for illegal purposes that could have international repercussions; one good example involves the RAPTORS system being used to smuggle illegal drugs across the U.S.-Mexico border. Prevention of serious political repercussions, while a design consideration, is not preventable.

Manufacturability: All of the parts used for this design are available off-the-shelf on the commercial market; the only proprietary systems are the PCB and software design. Thus this design would certainly lend itself to mass manufacture. There are only two areas of concern when considering manufacturability: first, the possible limited stock of certain parts. For example, the C328-7640 JPEG camera is being phased out in favor of a newer model, and is in short supply. The other concern is our use of breakout boards for certain sensors. Because these sensors were only available in leadless packages and leadless soldering methods weren’t available to our team, this was necessitated; a mass manufactured design would most likely be redesigned to use the leadless packages instead of the breakout boards in our design.

(f)  Description of the multidisciplinary nature of the project.

The RAPTORS system incorporates a variety of systems that require a true multi-disciplinary team. The main functionality of the system revolves around a custom designed RF and amplification system, which requires heavy communication system design skills in addition to experience with power systems. The sensor interfacing required experience with embedded system design and software, while the Virtual Cockpit on the laptop incorporated software engineering skills. Finally, designing the system to fit properly into the highly constrained spaces of the plane required both electrical and mechanical expertise.

(g)  Description of project deliverables and their final status.

The objective of the RAPTORS project was to be able to deliver the following: an RC plane outfitted with control, data gathering, and proprietary wireless modem systems; a ground station with the same wireless modem designed to transmit control signals to and receive sensor data from the aircraft and that interfaces with a PC running a proprietary control application; and a Windows executable that interprets control data from a joystick and sends it to the ground station and receives the sensor data from the ground station and displays it in a visual manner. All the deliverables are in their final and complete state and are fully functional; the only exception is the collection of camera data, which is functional but unreliable.

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