Final Report
Automatic Pet Feeder Using Radio Frequency Technology
ECE4884 Senior Design Project
Section L02, Fauler Hund Team
Robert Fleming
Kevin Clark
Viet Nguyen
Vu Tang
Vishak Ganesh
Submitted
December 7, 2007
Fauler Hund (ECE4884L02)
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TABLE OF CONTENTS
Executive Summary..........................................................................................................iii
1. Introduction ................................................................................................................. 1
1.1
1.2
1.3
Objective ............................................................................................................. 1
Motivation ........................................................................................................... 1
Background ......................................................................................................... 1
2. Project Description and Goals .................................................................................... 2
3. Technical Specifications .............................................................................................. 3
4. Design Approach and Details………………………………………………………..4
4.1 Design Approach .................................................................................................. 4
4.2 Codes and Standards........................................................................................... 11
4.3 Constraints, Alternatives, and Tradeoffs ............................................................ 11
5. Schedule, Tasks, and Milestones .............................................................................. 12
6. Project Demonstration .............................................................................................. 13
6.1 Overview ............................................................................................................ 13
6.2 Project Demo Instructions .................................................................................. 13
7. Marketing and Cost Analysis ................................................................................... 14
7.1 Marketing Analysis ............................................................................................ 14
7.2 Cost Analysis ...................................................................................................... 15
8. Summary and Conclusions ....................................................................................... 17
9. References .................................................................................................................. 18
Appendix A - Schematics
Appendix B – Parts List
Appendix C – Source Code
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EXECUTIVE SUMMARY
There are numerous automatic pet feeding devices on the market. Our prototype (the
FH-418) is a modification of an existing pet feeder on the market. The FH-418 allows the pet to
better regulate its feeding cycle, resulting in more free time for pet owners. The long term
objective is to make FH-418 a common house-hold product.
The pet feeder is controlled by a microcontroller. A transmitter, located around the pet’s
neck, sends a binary code to the receiver. This numerical identifier 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.
The prototype is made up of 5 major components that were successfully integrated
These components are the transmitter, receiver, microcontroller, relay, and feeder. However,
during the microcontroller implementation phase, integrating the Cypress with the rest of the
components proved to be more difficult than expected. This problem was due to a lack of
technical support and adequate software documentation. To resolve this issue, the PIC was
chosen to replace the Cypress microcontroller. Additional work that could improve the project
include increasing the auger speed to dispense food faster, increasing the battery life from its
original design of three months to approximately six months, proper packaging of chip
components, and a more user-friendly interface. All of these improvements would make the
product more marketable.
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Automatic Pet Feeder Using Radio Frequency Technology
1.
INTRODUCTION
Over half of American households have pets [1]. Feeding these pets can sometimes be
time consuming. FH-418 solves this issue by reducing the amount of time the pet owner spends
on feeding the pet.
1.1
Objective
The automated pet feeder allows pet owners to conveniently feed their pets. Reliable
automatic pet feeders have the potential to ease the schedules of busy pet owners. Existing timer
based automatic feeders on the market are improved 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
The 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. However, FH418 will resolve the issue by only feeding a pet with a specific numerical ID.
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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 overeat;
other pets may eat the food; and food will not remain fresh. Timer based feeders are more
expensive and dispense set amounts of food at specified periods of the day [2]. Although this
mechanism addresses the issue of overeating, it neglects the problem of keeping food fresh and
the issue of other animals eating the pet’s food. This project, however, solves all of these
problems by using a transmitter and receiver between the pet’s collar and the feeder. By
recognizing that the pet is within close proximity, the dispenser releases a predetermined amount
of fresh food.
2.
PROJECT DESCRIPTION AND GOALS
The prototype pet feeder uses a numerical identification feature based on RF technology.
The goal of the pet feeder is to automatically feed a particular pet when it comes up to the bowl.
In addition, the feeder employs a timer to control the amount of food dispensed to prevent
overeating.
The product’s final selling price is estimated to be $165. This price is $10 to $85 more
than similar food dispensers in the market. However, this difference in cost can be attributed to
better technology. As the component costs of the feeder decreases, the product becomes more
affordable to a wider range of pet owners.
The functionalities of our product include the following:

Automates feeding

Dispenses preset amounts of food

Recognizes specific pets via collar transmitter
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
Holds a reservoir of food

Requires low maintenance

Prevents the pet from overeating

Prevents food being eaten by other animals
These features have all been successfully implemented in the final design. However,
future improvements could include increasing the food dispensing rate, the battery life, and
improving user-friendliness by adding a LCD interface.
3.
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
Desired Specifications
3 to 6 ft
< 2 minutes
< 6 ounces
4 bit binary code
Does not impede pet
6+ months
Small cell battery
Standard household AC
Motor powered
Size based on pet breed
Accurate to a minute
IR/RF Technology
Actual Specifications
9 ft
10 seconds
< 6 ounces
10 bit tristate binary code
Does not impede pet
1.5 months
3-V Coin cell battery
Standard household AC
DC Motor
Size based on pet breed
Accurate to a minute
RF Technology
Most of the desired specifications have been met. However, the transmitter weight would
increase following packaging. Currently the weight of the transmitter is within the 6 ounce limit.
The antenna would also have to be modified to have a range shorter than 9 feet. In addition, the
battery life will have to be increased in order to achieve the desired 6 month lifespan. Lastly, the
speed of the auger will have to be improved.
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4.
DESIGN APPROACH AND DETAILS
4.1
Design Details
The FH-418 pet feeder is a modification of the Ergo AutoPetFeeder. The major
modification centers around the replacement of the old timer based controller with a new one
that uses a microcontroller and wireless link with a pet collar. This project created a prototype
device consisting of five main components, all of which are listed and summarized in Figure 1.
The FH-418 prototype pet feeder modifies the Ergo AutoPetFeeder product with its timer
removed. A hardware block diagram of the components used for the project is shown below.
Figure 1. Overall block diagram
A short range radio transmitter that is fitted around the pet’s collar functions as a wireless
tracking device. This radio transmitter is the TXE-418-KH2 chip sold by Linx Technologies. It is
a single unit that includes all the necessary radio frequency and encoding circuitry to wirelessly
transmit the value through ten data lines to an appropriate receiver. The antenna is the only
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external RF component. For this project's implementation, the receiver is the RXD-418-KH2
chip and acts as a matching component to the transmitter.
The pet feeder is primarily controlled by the PIC18F2321 microcontroller chip. This chip
determines the length of time that the auger spins, which dictates the amount of food dispensed.
The feeder itself is turned on and off by a relay circuit, which is powered by a standard 120V
outlet and controlled by the microcontroller.
The pet feeder's tracking device is separate from the rest of the system, and
communicates via encoded data packets transmitted on the 418 MHz radio band. All other
components are located on the pet feeder itself, and communicate using the connections
described in Figure 2.
Figure 2. High level interconnects
Connection C2 is from the valid transmission pin of the RXD chip to an input pin of the
PIC. Since the transmitter and receiver are operating simply as a detection method, only the
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reception of a signal is necessary. Connection C3 is from an output pin of the PIC to a
combination relay and buffer circuit which drives C5, the 120 Volt AC household current.
The General operating method for the FH-418 is described in the flowchart of Figure 3.
Figure 3. Operational flowchart
The basic component layout shows the feeding mechanism, the transmitter and receiver,
the PIC18F2321 microcontroller, and the relay. The moment the receiver detects a signal from
the transmitter, the valid transmission pin on the receiver goes high. The PIC microcontroller
receives this signal and executes the C code which determines the feeding duration. For the
relay to be started, the output of a comparator used must be about 5V. The motor then starts the
auger, causing the feeding dispenser to release the appropriate amount of food.
A detailed image of the transmitter is shown on the next page in Figure 4. This chip
consists of a RF transmitter with an on-board encoder. The default state of the pet feeder is
when the RXD chip is actively checking for a valid transmission signal. Once a valid
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transmission has been detected, the amount of food that is dispensed will be based on the total
time elapsed since the previous feeding cycle. In addition, the dip switch setting selected by the
user also affects the amount of food that is dispensed. Once pet has finished feeding, there is a 10
minute delay before the microcontroller renews the detection cycle.
Figure 4 displays the transmitter. On the upper left is the TXE chip with a helical antenna
linked to it. In order to create a proper short range radio device, the TXE chip needs to be altered
in ways. For decreasing the range of the transmitter, a helical antenna has been added. In
addition, a potentiometer is used to reduce the total output power.
Figure 4. Transmitter board and components
The TXE chip features ten tri-state address lines for matching transmitter and receiver
pairs. For this application, we use a ten- switch piano dip switch package to swap the address
lines from logical high to high impedance. The transmitter uses a three volt coin cell battery in
order to allow the transmitter to be attached to a pet collar without using a bulky battery. In
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order to improve battery life, the transmitter is controlled with a timer circuit that cycles it on and
off at regular intervals. The prototype uses a 555 timer chip to generate a low duty cycle square
wave that drives the transmit enable pin of the TXE chip. In order to follow the transmitter's on
off cycle, a small LED is connected to the output of the 555 timer to give visual confirmation.
This prototype transmitter is assembled according to the schematic detailed in Appendix A.
Figure 5. Receiver board and components.
The RXD chip on the bottom left, with the use of the helical antenna, receives a radio
transmission from the transmitter. The helical antenna on the receiver serves to further reduce the
effective range of the transmitter and receiver pair. Testing in the lab indicated an effective range
of about 3-8 feet depending on antenna orientation. A ten dip switch package located on the
receiver board is connected to the tri-state address lines as found in the transmitter. When these
address lines match those on the transmitter, the valid transmission will go high when the
transmitter's signal is detected. The receiver board also has a voltage regulator that regulates the
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voltage from a standard five volt AC power adapter. This voltage also powers the PIC
microcontroller board in Figure 6.
Figure 6. PIC board and components.
The PIC18F2321 microprocessor, serial adapter for programming the PIC, and a
comparator circuit that drives the relay is displayed in Figure 6. The PIC operates from a three
volt dc source which can be changed to a five volt source in a final product. This PIC serves as
the central control unit of the auto pet feeder. The dip switch (found on the top left hand corner)
can be used by the pet owner to control the amount of food that is dispensed by the feeder. The
receiver and PIC boards are built according to the schematic in Appendix A. Lastly, the feeder is
displayed in Figure 7.
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Figure 7. Pet feeder mechanism
The Pet Feeder shown in Figure 7 is a relatively primitive, consisting of a reservoir that
holds the food and an auger that pushes it food out. When supplied with an appropriate current,
the auger turns, forcing the pet food out of the spout in the front. Since the motor runs whenever
the unit is supplied with power, a control relay was needed for regulating the amount of food
dispensed.
Figure 8. Motor controller
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Figure 8 contains the circuit that controls the pet feeder's motor. The relay allows a small
DC current to control the much larger AC current utilized by the feeder motor. A buffer BJT and
the shunt diode prevents the large inductance present in the magnetic mechanism of the relay
from discharging into the microcontroller's output pin and allows the relay's coil to discharge
completely when not powered.
4.2
Codes and Standards
Complying with Part 15 of the FCC rules which states guidelines for RF devices such as
general technical and labeling requirements will be required [3]. As a result, production costs
will increase due to adhering to these rules. The feeder will use an American 3-pin/Type
B/NEMA 5-15 power plug and will follow guidelines for its design and use [4].
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 [5, 6]. Motion detection allows for
detection of an animal’s presence, but does not distinguish between animals.
For the transmitter, we initially chose a Cypress Microcontroller, but due to the lack of
documentation, a PIC microcontroller was chosen as an alternative. This PIC microcontroller
stays in a low-power mode that 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 does 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.
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5.
SCHEDULE, TASKS, AND MILESTONES
Gantt Chart of Projected Schedule
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The Gantt chart on the previous page presents the planned schedule of the project. All
aspects of the schedule were successfully completed, though minor variations in dates arose.
Integration of the microcontroller with the transmitter and receiver was the most difficult as
coding was required and members had little to no experience in hardware coding. Robert
Fleming led the hardware aspect of the project, specifically, the transmitter and receiver
integration. Kevin Clark was the webmaster and supported the microcontroller testing. Vishak
Ganesh tested functionality of the system. Viet Nguyen led the software aspect of the
microcontroller. Vu Tang tested in hardware functionality and assisted in the component
integration. All group members were involved with testing at each stage.
6
PROJECT DEMONSTRATION
6.1
Overview
The block diagram displayed in Figure 1 was successfully implemented in the
demonstration. All of the design goals set at the beginning of the project were achieved. The
transmitter emitted RF signals at consistent intervals without any complications. The
microcontroller effectively executed the project firmware upon receiving the valid transmission
signal from the receiver. Finally, the relay and feeder responded successfully to the output sent
from the microcontroller.
6.2
Project Demo Instructions
1. Set up the receiver, microcontroller, relay, and feeder as shown in Appendix A
2. Ensure that the VDD and GND pins of the receiver and microcontroller are connected to
identical pins.
3. Ensure that the valid transmission pin on the receiver is connected to pin 3 on the
microcontroller
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4. Connect pin 7 of the microcontroller to the input of the comparator
5. Connect the blue wire to the output of the comparator. In addition, connect the black wire to
voltage and the green wire to ground. (this step is crucial since the relay controls the feeder
using this output)
6. Bring the transmitter close to the receiver and begin demonstration
7. Refer to the schematic in the Appendix A for further clarification
PUT PICTURE OF DEMONSTRATION
7.
MARKETING AND COST ANALYSIS
7.1
Marketing Analysis
The primary objective of our device is to increase the ease with which the pet owner can
feed the pet. The pet feeder is especially appropriate for busy pet owners. The most advanced
pet feeders in the market today are based on timer technology. This project, however, takes the
next step towards automation by adding a sophisticated timer and a short range RF sensor. The
feeder dispenses food only when the pet is near the device. Many of the feeders on the market
are priced in the range of $80 to $135 [2]. Our product will be priced at around $165. So for a
marginally higher cost, the pet feeder includes newer technology that makes the pet feeding
process more convenient for owners. 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 it remains sealed for the majority of the time.
There are currently an estimated 140 million dogs and cats in the United States [1]. The
households that own these 140 million domestic pets will be our primary market. By using short
range RF technology, this pet feeder will gradually become a viable and desired substitute for
timer based feeders.
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7.2
Cost Analysis
Table 1 below shows a cost analysis of parts necessary to build the prototype pet feeder.
Item
Dog Feeder
Microcontroller
Relay
Motor
Sensors (Tran/Rec)
Encoder/Decoder
Power Supply
Bowl
Container
Base
Dispenser
Table 1 Automated Pet Feeder Cost
Qty
Cost
Total
1
$100
2
$15
1
$2
1
$5
2
$4
2
$3
1
$10
1
$3
1
$3
1
$3
1
$3
Misc Parts
$100
$30
$2
$5
$8
$6
$10
$3
$3
$3
$3
10%
$17
Total
$190
The initial construction cost of the prototype will be higher than final production cost
because certain materials will be purchased directly from retailers. Each team member is
expected to work an average of 8 hours a week. Half of weekly labor time was spent in class
lectures and group meetings on progress and issues, and the other half was spent on direct project
work and documenting design implementation. The team members spent a total of
approximately 64 hours per member to complete this project. At a rate of $50/hour for each
engineer, we see a total development cost of $16,000.
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
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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
17,925
4,481
22,956
12,626
$35,582
Determination of Selling Price
What the customer pays the company for the finished product
Based on:
1,500,000
Units
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 12.40%
$165
$247,500,000
$30,781,601
Our group projects a 12.40% profit margin over a five year period at a selling price of
about $165 per each unit. This 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, 7].
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8.
SUMMARY AND CONCLUSIONS
The primary objectives outlined in the beginning of the project were to build a pet feeder
that is cost effective and convenient. The prototype achieves these goals. At the beginning of
the project, RFID technology seemed to be a feasible way to implement the project. However,
due to the high cost of RFID technology, the primary design goals needed to be modified.
Standard RF technology was chosen as the best alternative to RFID. After completion of the
prototype, RF technology was determined to be both cost effective and easy to implement.
Several improvements are critical for the prototype to become a marketable product.
These improvements include increasing the battery life, increasing the speed of the auger, and
packaging the transmitter, receiver, and microcontroller. Since the prototype passed all
preliminary testing, only the improvements listed above will be required to make it more
marketable. FH-418 is a perfect fusion of technological prowess and simplicity of design.
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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&origkw=dog+fee
der&kw=dog+feeder&parentPage=search&keepsr=1
[3]
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/part155-4-07.pdf
[4]
Wikipedia Contributors “NEMA Connector” [Online Encyclopedia], 2007 September 4 [cited
2007 September 14], Available HTTP: http://en.wikipedia.org/wiki/NEMA_connector
[5]
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
[6]
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&cPath=6
[7]
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&Product_
Code=LAPF&Affiliate=nextag
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Appendix A - Schematics
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A1
Receiver, Relay, and Microcontroller Circuit
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A2
Appendix B – Parts List
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B1
Appendix C – Source Code
/******* Template.c
************************************************************
*
* Template program for Design Project.
* Use Fosc = 4 MHz for CPU clock of Fosc/4 = 1 MHz (on pin 10)
* Toggle RC2 output every 16 milliseconds for measuring looptime with
scope.
* Blink "Alive" LED on RB6 every four seconds.
* Check pushbutton and turn on "Alive" LED continuously while it is
pressed.
* Send initial message to PC.
* Use 16 ms (nominal) watchdog timeout for looptime.
*
*
Current draw = 3 uA (with LED removed)
*
******* Program hierarchy
*****************************************************
*
* Mainline
* Initial
*
PCdisplayC
*
TXbyte
* BlinkAlive
* Pushbutton
* LoopTime
*
***********************************************************************
********
*/
#include <p18f2321.h>
/*******************************
* Assembler directives
*******************************
*/
#pragma config OSC = INTIO2
RA7=I/O
#pragma config BOR = SOFT
#pragma
nominal
#pragma
#pragma
#pragma
nominal
#pragma
#pragma
#pragma
config BORV = 2
config PWRT = ON
config WDT = OFF
config WDTPS = 4
config MCLRE = ON
config PBADEN = DIG
config LVP = OFF
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// Use internal osc, RA6=Fosc/4,
// Brown-out reset enabled/disabled in
// software
// Brown-out voltage set for 2.7V,
// Disable watchdog timer initially
// 16 millisecond WDT timeout period
// PORTB<4:0> = digital
C1
/*******************************
* Definitions and equates
*******************************
*/
/*******************************
* Global variables
*******************************
*/
unsigned int ALIVECNT;
LED
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
// Counter for blinking "Alive"
int FEEDCOUNT;
char NEWPB;
char OLDPB;
long TOTALCOUNTS;
long FEEDAMOUNT;
long WAITPERIOD;
long DIPVALUE;
int RIGHTPATH;
int a0, a1, a2, a3, a4, a5, a6, a7, x, TEN;
long TIMEDIFF;
long XD;
/*******************************
* Constant strings
*******************************
*/
const char rom MESSAGE[] = "Eat at Joe's\r\n";
const char rom NEWMESSAGE[] = "Running\r\n";
/*******************************
* Variable strings
*******************************
*/
/*******************************
* Function prototypes
*******************************
*/
void
void
void
void
void
void
Initial(void);
PCdisplayC(const char rom *);
TXbyte(char);
BlinkAlive(void);
Pushbutton(void);
LoopTime(void);
void CountDown(void);
void DipSwitch(void);
void FeedTime(void);
void InputSignal(void);
/////// Mainline program ////////////////////////////////////////
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C2
/*******************************
* main()
*******************************
*/
void main()
{
Initial();
// Initialize everything
while (1)
{
PORTCbits.RC2 = !PORTCbits.RC2;
if(RIGHTPATH == 0)
{
BlinkAlive();
//Pushbutton();
InputSignal();
}
else if(RIGHTPATH == 1)
{
FeedTime();
}
else
{
CountDown();
}
/*
if(PORTAbits.RA1){
PORTAbits.RA7 = 1;
}else {
PORTAbits.RA7 = 0;
}
*/
LoopTime();
// Blink "Alive" LED
// Set for 16 ms by watchdog timer
}
}
/*******************************
* Initial()
*
* This subroutine performs all initializations of variables and
registers.
*******************************
*/
void Initial()
{
RCONbits.SBOREN = 0;
disable
OSCCON = 0b01100010;
CPU clock)
ADCON1 = 0b00001111;
TRISA = 0b00010011;
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// Start up with brown-out reset, then
// Use 4 MHz internal oscillator (1 MHz
// Make all ADC/digital pins digital
// Set I/O for PORTA
C3
TRISB = 0b00111111;
// Set I/O for PORTB
TRISC = 0b11000000;
// Set I/O for PORTC (set as input by
openi2c)
PORTA = 0;
ALIVECNT = 0;
// Initialize the BlinkAlive variable
////////////////////////////////////////////////////
FEEDCOUNT = 0;
// Count for how long between last
feeding time
FEEDAMOUNT = 0;
// Count for how long to feed
WAITPERIOD = 0;
// Count for 2 hour delay
DIPVALUE = 0;
// Actual feeding period
RIGHTPATH = 0;
a0 = 0;
a1 = 0;
a2 = 0;
a3 = 0;
a4 = 0;
a5 = 0;
a6 = 0;
a7 = 0;
/*PORTAbits.RA7 = 0;
PORTBbits.RB0 = 1;
PORTBbits.RB1 = 1;
PORTBbits.RB2 = 1;
PORTBbits.RB3 = 1;
PORTBbits.RB4 = 0;
PORTBbits.RB5 = 0;
PORTAbits.RA0 = 0;
PORTAbits.RA1 = 0;*/
x = 0;
INTCON2bits.RBPU = 0;
PORTAbits.RA1 = 0;
TIMEDIFF = 0;
XD = 0;
TEN = 0;
/////////////////////////////////////////////////////
SPBRG = 51;
// set up UART
SPBRGH = 0;
NEWPB = 0;
OLDPB = 0;
TOTALCOUNTS = 0;
RCSTA =
TXSTA =
SPBRG =
BAUDCON
0b10010000;
0b00100000;
12;
= 0b00111000;
//
//
//
//
Enable UART
Enable TX
Set baud rate
Invert TX output
PCdisplayC(MESSAGE);
PIE1bits.TMR1IE = 1;
TMR1H = 0xFF;
TMR1L = 0x00;
T1CON = 0b01001111;
PIR1bits.TMR1IF = 0;
INTCONbits.GIEL = 1;
Fauler Hund (ECE4884L02)
//
//
//
//
//
//
Enable local interrupt source
Initial value
Timer1 runs from 32768 Hz oscillator
Clear Timer1 flag
Enable wake-up from sleep
C4
// WDTCONbits.SWDTEN = 1;
}
// Enable watchdog timer
/*******************************
* PCdisplayC(const char *)
*
* This function sends a constant string to the PC.
*******************************
*/
void PCdisplayC(const char rom * strPtr)
{
while ((*strPtr) != 0)
// send all bytes until zero
{
TXbyte(*strPtr++);
}
}
/*******************************
* TXbyte(char)
*
* Sends out a character to the terminal
*******************************
*/
void TXbyte(char in)
{
while (!PIR1bits.TXIF) ;
TXREG = in;
}
/*******************************
* BlinkAlive()
*
* This subroutine briefly blinks the LED every four seconds.
* With a looptime of about 10 ms, count 200 looptimes
*******************************
*/
void BlinkAlive()
{
PORTAbits.RA7 = 0;
// Turn off LED
if (++ALIVECNT >= 100)
// Decrement counter and return if
not zero
{
ALIVECNT = 0;
// Reinitialize ALIVECNT
// 10.0 ms * 200 counts = 2000 ms
PORTAbits.RA7 = 1;
// Turn on LED for 10 ms every 2 secs
//...
}
}
/*******************************
* Pushbutton()
*
Fauler Hund (ECE4884L02)
C5
* This subroutine, called from the mainline loop, after the BlinkAlive
call,
* echos the state of the pushbutton on the LED.
*******************************
*/
void Pushbutton()
{
++FEEDCOUNT;
++TIMEDIFF;
PORTAbits.RA5 = 1;
// Power up the pushbutton
Nop();
// Delay one microsecond before
checking it
NEWPB = !PORTAbits.RA4;
// Set flag if pushbutton is pressed
PORTAbits.RA4 = 0;
// Power down the pushbutton
if (!OLDPB && NEWPB)
// Look for last time = 0, now = 1
{
//save time and restart timing:
TOTALCOUNTS = FEEDCOUNT;
FEEDCOUNT = 0;
if(TOTALCOUNTS/100 > 10)
{
RIGHTPATH = 1;
FEEDAMOUNT = 0;
XD = TIMEDIFF/100;
TIMEDIFF = 0;
DipSwitch();
}
}
OLDPB = NEWPB;
// Save present pushbutton state
}
void InputSignal()
{
++FEEDCOUNT;
++TIMEDIFF;
Nop();
if(PORTAbits.RA1 == 1)
{
while(++TEN < 1000)
{
PORTCbits.RC2 = !PORTCbits.RC2;
LoopTime();
++TIMEDIFF;
}
if(PORTAbits.RA1 == 1)
{
TOTALCOUNTS = FEEDCOUNT;
FEEDCOUNT = 0;
RIGHTPATH = 1;
FEEDAMOUNT = 0;
TEN = 0;
WAITPERIOD = 0;
XD = TIMEDIFF/100;
TIMEDIFF = 0;
Fauler Hund (ECE4884L02)
C6
DipSwitch();
}
}
}
/*******************************
* LoopTime
*
* This function puts the chip to sleep, to be awakened by Timer1
rollover.
*******************************
*/
void LoopTime()
{
while(!TXSTAbits.TRMT);
//wait for transmissions to finish
Sleep();
Nop();
T1CONbits.TMR1ON = 0;
// Pause Timer1 counter
TMR1L += 0xB9;
// Cut out all but 328 counts of Timer1
T1CONbits.TMR1ON = 1;
// Resume Timer1 counter
TMR1H = 0xFE;
// Upper byte of Timer1 will be 0xFE
PIR1bits.TMR1IF = 0;
// Clear interrupt flag
}
/*******************************
* CountDown()
*
* This subroutine delays the pic from reading signal from receiver for
2 hrs.
* With a looptime of about 10 ms, count 720000 looptimes
* 10.0 ms * 400 counts = 4000 ms
*******************************
*/
void CountDown()
{
++TIMEDIFF;
//PORTAbits.RA7 = 0;
// Turn off LED
if (++WAITPERIOD >= 3000)
// Decrement counter and return
if not zero
{
RIGHTPATH = 0;
}
}
/*******************************
* FeedTime()
*
* This subroutine turns on motor for specific amount of time.
* based on DIPVALUE ,
10.0 ms * 400 counts = 4000 ms
*******************************
*/
void FeedTime()
{
Fauler Hund (ECE4884L02)
C7
if (++FEEDAMOUNT >= DIPVALUE)
return if not zero
{
PORTAbits.RA3 = 0;
PORTAbits.RA0 = 0;
PORTAbits.RA7 = 0;
RIGHTPATH = 2;
CountDown
}
else
{
PORTAbits.RA7 = 1;
PORTAbits.RA3 = 1;
PORTAbits.RA0 = 1;
}
}
// Decrement counter and
// Turn off RELAY
// Turn on RELAY
// Turn off LED
// Change RIGHTPATH to 2 to go into
// Turn on LED
// Turn on RELAY
// Turn on RELAY
/*******************************
* DipSwitch()
*
* This subroutine calculates the amount of time to turn on motor
* by taking in values from input pins from PORTB and PORTA
* 10.0 ms * 400 counts = 4000 ms
*******************************
*/
void DipSwitch()
{
x= PORTB & 0x3F;
if(x >= 50)
{
DIPVALUE = XD * .25;
}
else if(x >= 20 && x < 50)
{
DIPVALUE = XD * .24;
}
else
DIPVALUE = XD * .225;
if(DIPVALUE < 30000)
DIPVALUE = 3000;
else if(DIPVALUE > 180000)
DIPVALUE = 18000;
else
DIPVALUE = DIPVALUE;
}
Fauler Hund (ECE4884L02)
C8