Highway Deer Identification System

Design Report

May 07-11

Client:

Senior Design

Advisor:

Dr. Degang Chen

Team Members:

Tony DeLouis

Matt Bonneau

Nathan Schoening

Steven Schreiber

REPORT DISCLAIMER NOTICE

DISCLAIMER: This document was developed as a part of the requirements of an electrical and computer engineering course at IowaStateUniversity, Ames, Iowa. This document does not constitute a professional engineering design or a professional land surveying document. Although the information is intended to be accurate, the associated students, faculty, and IowaStateUniversity make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. This use includes any work resulting from this student-prepared document that is required to be under the responsible charge of a licensed engineer or surveyor. This document is copyrighted by the students who produced this document and the associated faculty advisors. No part may be reproduced without the written permission of the senior design course coordinator.

11-10-06

Table of Contents

ItemPage

List of Figures

List of Tables

List of Equations

List of Definitions

Executive Summary

Acknowledgements

Problem Statement

Operating Environment

Intended Users and Uses

Assumptions

Limitations

Expected End Product

Approach

Design Objectives

Functional Requirements

Input and Output

Filtering and Amplification

Signal Processing

LED warning system

PV system

Design Constraints

Technical Approach Considerations and Results

Testing Approach Considerations

Test Planning

Test Development

Test Execution

Test Evaluation

Test Documentation

Recommendations Regarding Project Continuation or Modification

Detailed Design

Geophone

Low Pass Filter and Amplifier

Microcontroller

Warning System

Photovoltaic System

Loads

Batteries

Photovoltaic Panels

Charge Controller

Resource Requirement

Personal Effort Requirements

Other Resource Requirements

Financial Requirements

Schedules

Project Schedule

Deliverable Schedule

Project Team Information

Client information

Faculty advisor information

Student team information

Closing Summary

References

List of Figures

ItemPage

Figure 1: Process Diagram for Highway Deer Identification System

Figure 2: Geophone w/o connectors or ground spike

Figure 3: Butterworth low pass active filter

Figure 4: Schematic Diagram of Warning Circuit

Figure 5: Drawing of LED and LED Spec Sheet

Figure 6: Graphic Representation of System

Figure 7: Block Diagram of System

Figure 8: Battery

Figure 9: Solar Panel

Figure 10: Charge Controller

Figure 11: Gantt Chart

Figure 12: Deliverable Schedule

List of Tables

ItemPage

Table 1: Geophone Spec Sheet

Table 2: Microcontroller Spec Sheet

Table 3: Layout of Microcontroller Pins

Table 4: Loads of the System

Table 5: Battery Specification Equation

Table 6: Photovoltaic Panel Equation

Table 7: Charge Controller Equations

Table 8: Effort Requirements

Table 9: Cost Analysis

List of Equations

ItemPage

Equation 1

Equation 2

Equation 3

Equation 4

List of Definitions

Ampacity – The amount of electrical current a particular cable is rated to carry. This depends on the size of the conductor and the ambient temperature.

Automatic equalization – Ensures that all cells in the battery are fully charged.

Charge controller – A device that controls the voltage across and current into a battery to facilitate charging.

Current – The amount of electric charge moving through a cross-sectional area per unit of time. Current is measured in Amperes (amps), and is vaguely analogous to flow in a fluid system.

DOT – Department of Transportation.

Geophone – A device for detecting and/or measuring vibrations in the ground.

Global positioning system (GPS) – A system of orbiting satellites used to triangulate a position on earth.

Infrared (IR) – Refers to electromagnetic radiation that is slightly below the red end of the visible spectrum, with wavelengths ranging from about 700 to 1 million nanometers.

Inverter – A high-power electronic device that converts direct current electrical power into alternating current electrical power.

Jacket – The outermost layer on a cable, and is intended to protect the cable from physical damage.

Light emitting diode (LED) – A semiconductor device that only allows current to flow in one direction, and gives off light when it is conducting.

Maximum power point tracking – A feature of a charge controller that allows the solar panels to operate at the voltage level that maximizes power output while still providing the correct voltage to charge the battery.

Photovoltaic (PV) – Describes equipment/components that convert sunlight into electricity.

Temperature compensation – Adjusts the voltage and current being used to charge the battery for different ambient temperatures.

Voltage – A measure of electric potential energy per unit charge. Voltage is measured in Volts, and is vaguely analogous to pressure in a fluid system.

Executive Summary

The Highway Deer Identification System is intended to detect deer on/near a road and warn motorists to their presence, hopefully reducing rates of deer-vehicle accidents. The system is required to detect deer within 25 feet of the highway, and track them across it. It must be able to function in remote areas, under a wide variety of environmental conditions, and without a utility-supplied electric grid.

The system will use geophones to detect vibrations in the ground caused by deer movement. The signal from the geophones will be analyzed to determine whether the vibrations were caused by deer, and if so, a signal will be triggered to warn motorists. The system will be powered by a standalone photovoltaic system.

The expected end product is a component-level design for the system. Any specific site where the system might be installed will present its own challenges and limitations. As such, the final design will be a baseline, which can be adjusted to meet any specific needs or criteria. The intended end users are the workers who install and maintain the system, and the motorists the system is intended to protect.

The design process was heavily focused on selecting a technology for detecting the presence of deer. Factors considered included accuracy, security from unintended operation, cost to install and maintain, and the team’s resources and skills. Geophones were selected over several other options, including infrared imaging, infrared motion detectors, and a “break-the-beam” system of IR or laser transmitters and receivers.

Geophone systems have been deployed experimentally elsewhere, and have the highest experimental accuracy of any of the alternatives considered. “Break-the-beam” systems are not very discerning, and there was concern with foliage near the road interfering with them. Infrared imaging is very accurate, but the cameras are expensive. Infrared motion detectors (very similar to what is used in home security systems) and geophones were the two most viable options, and our (preliminary) estimates indicate that geophones will be more cost-effective, more accurate, and less susceptible to damage than infrared motion detectors. The design of the photovoltaic power system and the active warning system were relatively straightforward.

The primary issues that need to be resolved relate to obtaining information about the seismic signatures of various things and processes. Specifically, it is very difficult to find exactly a geophone outputs when a deer is walking within its range. Without this, it becomes very challenging to design an algorithm for the microcontroller to detect it. It is also difficult to find out what influence such things as traffic, rain, or thunder might have. Different geophone manufactures have been consulted, but the information conflicts. Based on the fact that a geophone system has been successfully implemented in Wyoming, it seems that these problems should be surmountable. Attempts to contact the team that designed the system in Wyoming have insofar been unsuccessful.

Acknowledgements

Geophones were selected over several other options, including infrared imaging, infrared motion detectors, and a “break-the-beam” system of IR or laser transmitters and receivers. Geophone systems have been deployed experimentally elsewhere, and have the highest experimental accuracy of any of the alternatives considered. “Break-the-beam” systems are not very discerning, and there was concern with foliage near the road interfering with them. Infrared imaging is very accurate, but the cameras are expensive. Infrared motion detectors (very similar to what is used in home security systems) and geophones were the two most viable options, and our (preliminary) estimates indicate that geophones will be more cost-effective, more accurate, and less susceptible to damage than infrared motion detectors.

The end product will be a component-level design for a system capable of fulfilling the functional requirements in the project description, as well as the constraints listed later in this report. The intended end users are the workers who install and maintain the system, and the motorists the system is intended to protect.

The project is estimated to cost $5,187 total, which consists of $200 in material costs for a prototype and $4987 in labor.

Problem Statement

The problem this project is intended to solve is that of deer-vehicle collisions. The system must be able to detect deer within 25 feet of the road and track them across it. It must also warn motorists to the presence of the deer, and it must be able to protect a mile of highway. It needs to work in all seasons, but particularly in the fall and spring when deer are chased out of fields by farming work. It must be deployable in remote areas where utility power is not available, and it must cost less than the next best alternative.

The approach being developed can be broken up into two broad parts: the subsystem that detects the deer and warns the motorist and the subsystem that provides power to the system (figure 1, below).

Figure 1: Process Diagram for Highway Deer Identification System

The detection subsystem will use geophones, which detect vibrations in the ground associated with deer movement. The geophones will be buried on both sides of the roadway such that their ranges overlap. This will enable the system to track the deer across the road (when the geophones on one side lose the deer, the geophones on the other side will pick it up).

Motorists will be warned by signs mounted periodically along the road with high-intensity light emitting diodes that illuminate when deer are present. The signs will be far enough ahead of the geophones that motorists have time to take defensive action, but not so far apart that motorists become complacent.

The system will be powered by a standalone photovoltaic (PV) system. The major components of the PV system are the solar panels, the batteries, and the charge controller. The solar panels generate electrical power from sunlight that falls on them, which is then stored in the batteries. The charge controller will keep the batteries charged while allowing the solar panels to operate at their maximum power range. At this point, only DC loads are anticipated, so an inverter will not be required. In addition to the major components, there will also be wiring, mounting equipment, and enclosures as dictated by the environment and applicable regulations/codes.

Operating Environment

The system will operate in a widely-varying environment. Being installed along rural Midwestern highways will expose it to a range of conditions. The climate will range from and potentially subzero temperatures in the winter to 90-100 degree heat in the summer. It will be exposed to rain, snow, and wind. It will have to withstand everything from road salt and snowplows to mowing and grazing in the right-of-way.

Intended Users and Uses

The intended users of the end product fall into two broad categories: the motorists the system is designed to warn, and the workers who install and maintain the system. Motorists could be anybody, but the system will be designed under the premise that they are legally able to drive, which in most states means they are at least 14 years old. The workers who install and maintain the system will likely have at least a high-school education, and will also have experience with electrical installations (they may even be licensed electricians).

The motorists will use the system as an indication that there are deer in the vicinity of the road. Ideally they will then take some sort of action. Aside from looking at the sign and seeing if the LEDs are flashing, motorists will have no other interaction with the system.

Assumptions

The following assumptions have been made during the course of the project to date:

The team will have a very limited supply of funds to develop the product
The most likely customer for this system would be a state Department of Transportation, and therefore the system should be installable and maintainable by the average Department of Transportation laborer
In order to be economically viable, the system should be less expensive per mile than using fences, which appears to be the most effective passive alternative
In order to be worth implementing, the system should be as effective at reducing deer-vehicle collisions as using fences, which appears to be the most effective passive solution
The system being triggered by things other than deer (people, an accident, other wildlife, etc.) is not a concern because the motorist will benefit from being warned of them
The system needs to be rugged enough to function year-round in remote locations with a minimum of maintenance
It is impractical to design a system that is impervious to vehicle collisions; however, the system should not make an accident more severe (e.g. the batteries should be housed such that a collision will not result in an acid hazard)
While the system is intended to fulfill a safety function and should be functional as much as possible, cost effectiveness should be an overriding factor
Being as the photovoltaic system is relatively straightforward, testing and prototyping will focus on the detection system

Limitations

In addition to the assumptions listed above, some limitations have been imposed:

The system must protect one mile of highway while ignoring cross streets, bridges and driveways

The system must be able to function without a connection to the electric grid
The system must be able to detect a deer 25 feet away from the road and track it across the highway until it is no longer a hazard
The system should not be susceptible to excessive nuisance alarms (i.e. cases where the system is triggered when there is no hazard present)

Expected End Product

The expected end product for this is a detailed, component-level design for a highway deer identification system that meets the criteria specified in the problem statement. This design will identify installation and wiring requirements and specifications for all components.

In addition to the design for the actual system, there will also be a prototype to verify that the system will be capable of fulfilling its design functions.

Approach

This section is dedicated to the design objective, functional requirements, and design restraints for the project. The section will explain each of the fore mentioned parts as well as describe the technical approach and results in designing the Deer Highway Identification System in detail. Finally, this section contains information about the methods of testing and other technologies that were considered.

Design Objectives

The approach to designing the Deer Highway Identification System is to research the circuits that are needed for the signal conditioning/amplification and LED lighting systems. Final circuits for the end-product will be decided on when tests are run of each circuit to optimize the desired results. Finally, the team’s ultimate goal is to create a product that can be easily implemented into practical road applications to warn a motorist of potential hazards.

After research and testing have been accomplished the design should remain under budget as much as possible. This includes all parts and components that are required for all systems and circuits both donated and purchased.