Proposal
Automated Pet Feeder
ECE4007 Senior Design Project
Section L02, Group 01
Kevin Clark, Robert Fleming, Vishak Ganesh, Viet Nguyen, Vu Tang
Submitted
September 17, 2007
TABLE OF CONTENTS
Executive Summary……………………………………………………………………... ii
1. Introduction………………………………………………………………………….. 1
1.1 Objective………………………………………………………………………... 1
1.2 Motivation………………………………………………………………………. 1
1.3 Background……………………………………………………………………... 1
2. Project Description and Goals……………………………………………………… 2
3. Technical Specification……………………………………………………………… 3
4. Design Approach and Details……………………………………………………….. 3
4.1
4.2
4.3
Design Approach………………………………………………………………...3
Codes and Standards.………………………………………………………….... 5
Constraints, Alternatives, and Tradeoffs………………………………………. 6
5. Schedule, Tasks, and Milestones…………………………………………………... 7
6. Project Demonstration……………………………………………………………... 8
7. Marketing and Cost Analysis…………………………………………………….... 8
7.1
7.2
Marketing Analysis……………………………………………………………. 8
Cost Analysis…………………………………………………………………... 9
8. Summary……………………………………………………………………………. 12
9. References…………………………………………………………………………... 13
EXECUTIVE SUMMARY
Our pet feeder is designed to make the pet feeding process more automated and
efficient. This pet feeder is controlled by a microcontroller. As the pet approaches the
feeder, the food is dispensed. A transmitter, located around the pet’s neck, sends a 16 bit
binary code to the receiver. This 16 bit binary code is a numerical identifier that will be
hard coded into the microcontroller. The numerical identification feature will allow the
pet feeder to identify a particular pet. Once this ID is verified, the pet feeder dispenses a
certain amount of food and closes the food latch. This process ensures that the stored
food remains fresh.
Our product’s selling price is $165. This price is $10 to $85 more than similar
food dispensers in the market. However, our food dispenser has the RF/IR ID capability
that will compensate for the higher cost. In addition, as the cost of ID tags and
components of the feeder decreases, the product becomes more affordable to a wider
range of customers. With over 140 million household pets in the U.S., we anticipate that
market for our product will be substantial [1].
If RF technology is used in our final design, we will need to comply with part 15
of the Federal Communications Commission to make our product legally marketable and
available for sale. The expected outcome of our project is to make a prototype that can
be turned into a common pet household product.
Automated Pet Feeder
1.
INTRODUCTION
Over half of American households have pets [1]. Feeding these pets can
sometimes be a chore. Our project aims to help pet owners reliably feed their pets while
saving time.
1.1
Objective
The automated pet feeder allows pet owners to conveniently feed their pets with
little to no human interaction. Reliable automatic pet feeders have the potential to ease
the schedules of busy pet owners. We seek to improve existing timer based automatic
feeders on the market by adding a pet identification system. The system’s main
components consist of the timer, a wireless interface, and a feeding mechanism. When a
pet approaches the food bowl at certain times, the pet feeder dispenses its contents.
1.2
Motivation
Our project modifies an existing product that will save pet owners time and
money. The automated pet feeder introduces the additional feature of pet identification.
This feature tailors to the needs of the pet and the pet owner’s lifestyle, providing
convenience and reliability.
1.3
Background
Automatic feeders on the market feed pets on a preset schedule [2]. However,
these timer based systems do not take into account the needs of the pet. This issue can
lead to wasted food or the food being eaten by another animal, in the case of an outdoor
feeder. Our product hopes to close this gap by only feeding the pet at the correct time
and when the pet is within three to six feet.
Examples of previous products include timer-based pet feeders and gravity-fed
feeders. The gravity feeder lacks any moving parts, is relatively inexpensive, and
dispenses food continually. This type of feeder has many disadvantages: the pet may be
encouraged to over-eat, other pets may eat the food when the pet is not nearby, and food
will not remain fresh. Timer based feeders are more expensive and dispense set amounts
of food at specified periods of the day. This mechanism addresses the issue of overeating,
but not the problem of other animals and stale food. Our project, however, addresses
these problems by using a transmitter and receiver between the feeder and the pet’s
collar. By recognizing that the pet is within close proximity, the dispenser would release
a predetermined amount of fresh food.
2.
PRODUCT DESCRIPTION AND GOALS
Our project is intended to create a prototype pet feeder with a numerical
identification feature based on RF or IR technology. An eventual outcome is to make our
feeder viable for mass production. The intent of the pet feeder is to feed a particular pet
when it comes up to the bowl. It accomplishes this task by the use of RF or IR
technology. In addition, the feeder would employ a timer to limit the number of feedings
a day to prevent overeating. The functionalities of our product will include the following:

Automates feeding

Dispenses preset amounts of food

Activates a certain number of times a day

Recognizes specific pets via collar transmitter

Holds a reservoir of food

Requires low maintenance
3.

Prevents the pet from overeating

Prevents food being eaten by other animals

Costs approximately $160

Pet owners as target audience
TECHNICAL SPECIFICATIONS
Aspect of Design
Transmitter/Receiver range
Time between transmitter pings
Transmitter weight (worn by pet)
Identifier Code
Transmitter size
Transmitter battery life
Transmitter power supply
Receiver power supply
Feeder mechanism
Container volume
Timer
Transmitter/Receiver
Design Specification
3 to 6 ft
< 2 minutes
< 6 ounces
16 or 32 bit digital signal
Small enough not to impede pet
6+ months
Small cell battery
Standard household AC; <20 Amps
TBD; motor powered
TBD; sizes based on pet breed
Accurate to a minute; time to be set.
TBD EM spectrum, i.e. RF or infrared
The pet feeder will weigh about two to three pounds and be less than three cubic
square feet in size. The feeder would run on household AC power so battery life will be
conserved. In order to reduce interference from similar transmitters, the ID tag will use a
multi-bit digital code.
4.
DESIGN APPROACH AND DETAILS
4.1
Design Approach
As a starting point for our project prototype, we plan to improve on an existing
timer-based product. We will modify this product by adding a microcontroller that
controls the dispensing mechanism. This microcontroller will receive inputs from the
timer and from the transmitter on the pet’s collar. The feeder dispenses food
automatically when the pet is nearby. The user will only need to interface with the timer
by setting up a specific feeding schedule that limits the number of time the pet feeds. The
hardware block diagram is shown below.
Figure 1. Hardware block diagram
Basic hardware components are outlined in Figure 1. The pet wears a transmitter
that broadcasts its identification code approximately every minute. This code is
transmitted to the receiver on the feeder and relayed to the microcontroller. Additionally,
the timer provides a signal to the microcontroller that initiates the feeding process. The
microcontroller will output a set of instructions to the feeder’s motorized mechanism,
which will dispense food.
The microcontroller will use a state machine as diagramed below.
Figure 2. Software state machine block diagram.
In Figure 2, the microcontroller will first wait for a timer signal and then the
transmitter signal. Once both signals are received, the feeder will dispense the pet’s food.
The implementation of the wireless link between the pet collar transmitter and the feeder
receiver has not been decided. We have narrowed our options to radio frequency or
infrared technology. The RF technology is prevalent in garage door openers and keyless
entry fobs for cars, and the IR technology is used by television remotes [4].
4.2
Codes and Standards
If we use an RF based communications link, we will need to comply with Part 15
of the FCC rules which states guidelines for RF devices such as general technical and
labeling requirements [3]. As a result, production costs will increase due to adhering to
these rules. Using an IR transmitter/receiver eliminates this problem [4]. Our feeder will
use an American 3-pin/Type B/NEMA 5-15 power plug and will follow guidelines for its
design and use [5].
4.3
Constraints, Alternatives and Tradeoffs
Some other design alternatives focused on the wireless link. RFID was initially
considered, but due to the high cost of RFID readers and a desire to make this pet feeder
affordable, RFID was rejected in favor of a simpler link [6, 7]. Motion detection allows
for detection of an animal’s presence, but does not distinguish between animals.
One of the constraints is the dimensions and weight of the RF/IR transmitter.
This constraint restricts the amount of power available. For the transmitter, we are
considering a PIC type microcontroller that will be used in a low-power mode, which
sends out a signal once a minute. This method allows the pet feeder to be programmed to
wait for two consecutive pulses. As a result, a pet randomly passing by the feeder will not
activate the food dispenser. Another constraint is the range of the transmitter/receiver.
By having the range relatively small, triggering only occurs when the pet is close enough
to the bowl.
SCHEDULES, TASKS, AND MILESTONES
Figure 3. Projected schedule of pet feeder project.
The Gantt chart on the previous page presents a projected schedule. Controlling the
feeder’s motor using the microcontroller is likely to be a straightforward task. Integration
of the microcontroller with the transmitter and receiver will be the most difficult, as the
interfaces of these devices are unknown at the moment. Robert Fleming will be the lead
in microcontroller design and programming transmitter integration. Viet Nguyen is the
webmaster and will help microcontroller transmitter integration. Vishak Ganesh will be
the lead in microcontroller design and programming receiver integration. Kevin Clark
will support the microcontroller receiver integration and transmitter design. Vu Tang is
lead in transmitter design and support with microcontroller receiver integration. All
group members will be involved with testing at each stage. Ordering parts will be a
group effort. Knowledge of programming the microcontroller is expected of all group
members. However, in case of potential issues, help is readily available.
6.
PROJECT DEMONSTRATION
Demonstration of our project will consist of filling the pet feeder with food,
setting the timer program, and bringing the transmitter close to the bowl to allow the
automatic dispensing of food. The pet collar will be placed on a large stuffed animal or
similar construction to ensure that the demo simulates a real life scenario. If time and
resources allow, however, video taping the automatic feeder being used by a real pet
would be more advantageous.
7.
MARKETING COST AND ANALYSIS
7.1
Marketing Cost
The primary objective of our device is to help create a more efficient method of
feeding pets. Our device is especially geared towards pet owners with hectic lifestyles.
The most advanced pet feeders in the market today are based on timer technology. Our
product, however, takes the next step towards automation. In addition to a timer, our
product will have an IR or short range RF sensor. IR or RF will be used in the form of an
ID tag that lets the feeder know when a dog is near the device. Many of the feeders on the
market are priced in the range of $135 [2]. Our product will be priced at around $165.
So for a marginally higher cost, our pet feeder provides newer technology that reduces
human effort. In addition, the pet feeder only releases a certain amount of food when the
pet is near and stops soon afterwards. This process ensures that the food is fresher as the
food remains sealed for the majority of the time.
There are currently 140 million estimated dogs and cats in the United States as of
2005 [2]. The households that own these 140 million domestic pets will be our primary
market. We are confident that our product design based on IR or short range RF
technology will gradually become a viable and desired substitute for timer based feeders.
7.2
Cost Analysis
Table 1 on the next page shows a cost analysis of parts necessary to build a
prototype pet feeder.
Table 1 Automated Pet Feeder Cost
Item
Dog Feeder
Micro-Control
Relay
Motor
Sensors
(Tran/Rec)
Encoder/Decoder
Power Supply
Bowl
Container
Base
Dispenser
Qty
1
2
1
1
Cost
$100
$15
$2
$5
Total
$100
$30
$2
$5
2
2
1
1
1
1
1
$4
$3
$10
$3
$3
$3
$3
$8
$6
$10
$3
$3
$3
$3
Misc Parts
10%
$17
Total
$190
The initial cost of prototype construction will be higher compared to the final
production cost because certain materials will be purchased straight off the shelf. As a
team, we expect to spend an average of 8 hours per week for each member. Half of
weekly labor time will be spent in class lectures and group meetings on progress and
issues, and the other half will be spent on direct project work and documentations of
design implementation. All labor time is based on developmental costs at standard
engineering rates. We predict an average of 120 engineering hours per group member,
summing up to a total of 600 development hours. At a rate of $50/hour for each
engineer, we see a total development cost of $30,000.
We project sales figures totaling upwards of 300,000 units per year for a total of
1,500,000 units over a five year period. This total represents approximately one percent
of the estimated 140 million pets in the United States [1]. The total cost of production
will be $9 for each unit. $6 will be spent on the assembly line, and $3 will be spent on
testing. Table 2 below shows the accumulation of total cost from initial development of
the prototype to mass production.
Table 2 Development Cost and Profit
Development Cost (Non-recurring Cost)
What it costs the company to develop the product
Parts
Labor
Fringe Benefits, % of Labor
Subtotal
Overhead, % of Matl, Labor & Fringe
Total
190
31,925
7,981
40,096
22,053
$62,149
Determination of Selling Price
What the customer pays the company for the finished
product
Based on:
1,500,000
Parts Cost
Assembly Labor
Testing Labor
Total Labor
Fringe Benefits, % of Labor
Subtotal
Overhead, % of Matl, Labor & Fringe
Subtotal, Input Costs
Sales & Marketing Expense
Warranty & Support Expense
Amortized Development Costs
Subtotal, All Costs
Profit
Selling Price
Total Revenue
Total Profit
50
6
3
9
2
61
34
95
41
8
0
144
21
$165
units
12.4%
$247,500,000
$30,781,601
Our group projects a 12.4% profit margin over a five year period at a selling price
of about $165 per each unit. This represents a $20 profit per unit sold. Our selling price
will be competitive compared to similar products such as Petmate’s Le Bistro and ERGO
System’s Autopetfeeder that sell at roughly $130 [2] [8].
8.
SUMMARY
We have done research on RF and IR communications. We have noted that they
are both low cost and readily available in the form of ICs. In order to decide between
these two technologies, we are consulting with various professors and different industry
experts. Once we have chosen, we will begin ordering of parts. Upon acquiring the parts,
we can begin the implementation of our prototype.
9.
REFERENCES
[1]
Pet Food Institute “Pet Population Data” [Online Document], 2006, [cited 2007
September 16], Available HTTP:
http://www.petfoodinstitute.org/reference_pet_data.cfm
[2]
“Petmate Le Bistro Electronic Portion Control Dog Feeder” [Online Catalog], [cited
13 September 2007], Available HTTP:
http://www.petsmart.com/product/index.jsp?productId=2751238&cp=&sr=1&origk
w=dog+feeder&kw=dog+feeder&parentPage=search&keepsr=1
[3]
Reynolds Electronics “Remote Control Store” [Online Catalog], [Cited 2007
September 14], Available HTTP:
http://www.rentron.com/PicBasic/RemoteControl.htm
[4]
Federal Communications Commission “Part 15 Regulations” [Online Catalog],
2007 May 4 [cited 2007 September 14], Available HTTP:
http://www.fcc.gov/oet/info/rules/part15/part15-5-4-07.pdf
[5]
Wikipedia Contributors “NEMA Connector” [Online Encyclopedia], 2007
September 4 [cited 2007 September 14], Available HTTP:
http://en.wikipedia.org/wiki/NEMA_connector
[6]
ZietControl Cardsystems GmbH “Online Order > Hardware” [Online Catalog],
2007 August 7, [Cited 2007 September 14], Available HTTP:
https://ssl14.pair.com/chippy/rfidrdr_or.php
[7]
Avid Wireless “RFID” [Online Catalog], 2005 April 27, [Cited 2007 September
14], Available HTTP:
http://www.avidwireless.com/AVIDCart/scripts/index.php?main_page=index&cPat
h=6
[8]
The Pampered Pet Mart “Feeding and Watering Products” [Online Catalog], [cited
13 September 2007], Available HTTP:
http://www.thepamperedpetmart.com/Merchant2/merchant.mvc?Screen=PROD&Pr
oduct_Code=LAPF&Affiliate=nextag