usf college of engineering eel 4906.001 - engineering design1 term & meeting info: spring 2015....
TRANSCRIPT
PDRAUTOMATIC PET FEEDER
USF college of engineering
EEL 4906.001 - Engineering Design1
Term & Meeting Info: Spring 2015. M 6:30pm – 9:15pm.
Angelina Colannino, John Hook, Kjersti Raabe, Brian Wagner
Automatic Pet Feeder
Programmable, RFID controlled automatic feeder
User defined scheduled feeding time
Minimal product management required
Current Model
Project Driving Requirements
1. RFID Tags must be in range Must operate with material between tag and
receiver
2. RFID receiver must operate without tag collisions
3. Timer Interface must be defined by user Must store 3 set times Must take input from interface
4. Motor Circuits triggered by logic circuit/timer
5. Power Supply
1. RFID tags in range
Material must be thin enough to avoid interfering with RF signal.
Receiver must be mounted on front of module so that tags can be within 4” range.
Receiver must be mounted parallel to front of module in order to receive signal
Tags operating on frequency of 125 kHz
2. RFID tag collisions
Receiver must sense presence of RFID tags without error
The presence of more than one tag may cause tag collisions, which result in receiver error.
Test plans include tag collision experiment.
3. User-defined timing
Timer must be set by interface screen/buttons on front of module.
Screen must display current time, as well as interface for setting feeding times.
Timer must store up to 3 feeding times.
4. Motor circuits trigger
Motor circuit must respond to trigger from logic circuit.
Logic circuit must take input from RFID receiver as well as timer.
Trigger must be produced when both timer signal is present and RFID tag signal is received.
Typical servos operate from PCM signals
5. Power supply
Primary: 120 VAC-4.5VDC (regulate between 4-6 V)
step down transformer power supply Secondary:
Battery Back-up (Alkaline) 4.5 V DC 42 hrs when in active use 10-year shelf life
http://www.energizer.com/batteries/energizer-max-alkaline-batteries#dhttp://data.energizer.com/PDFs/e95.pdf
5. Power Supply (cont.)Voltage Regulator LM7805 would make most sense for designing/regulating the power supply if using a chip to do so
5. Power Consumption
RFID Reader 4.5-5.5 VDC
Arduino Uno Operating Voltage 5V Input Voltage Limits 6-20V
Servomotors 4-6V DC Maximum current draw is 140 +/- 50 mA at 6 VDC
when operating in no load conditions, 15 mA when in static state
file:///C:/Users/John-Hook/Desktop/28140-28340-RFID-Reader-Documentation-v2.3.pdf
https://www.parallax.com/sites/default/files/downloads/900-00005-Standard-Servo-Product-Documentation-v2.2.pdf
Top-Level System Diagram
Internal Interface
Self contained
Subsystems interface with each other RFID serial connection with Arduino Timing Logic Circuit
Verification
RFID sensor Range Interference Tag collisions
Timing Circuit Interface operation Produce trigger Storage
Servo Motors Respond to trigger Weight/strength
State Transition Diagram
Data Flow Diagram
Data Flow Diagram
Sequence Diagram
Technical Trades
Arduino Code vs. User Interface Corkscrew vs. “Water Wheel” Dispenser Drawer vs. Door Scale vs. Clear Reservoir Wi-Fi vs. Manual Setting Alarm tone vs. Voice
Project Test Plans: Initial Verification
RFID sensor Range Interference Tag collisions
Timing Circuit Interface operation Produce trigger Storage
Servo Motors Weight/strength
Project Test Plans: General Construction
Temperature Place system in extreme temperatures and
verify operation. Accessibility
Test operation of lid on top of module. Test operation of buttons/screen
Capacity Test amount of food reservoir can hold
Project Test Plans: RFID
Range Read data from RFID receiver, holding tags at
several different distances. Interference
Read data from RFID receiver when different materials are used for module.
Project Test Plans: Timing Circuit
User-defined Settings Use interface to set 3 separate feeding times. Demonstrate that the feeding times produce a
trigger. Storage
Demonstrate that feeder will store three feeding times at once.
Project Test Plans: Motor Circuit
Trigger Produce trigger from timing and RFID receiver
to demonstrate that motor will respond. Drawers
Demonstrate that motor can move the drawer. Refilling mechanism
Produce trigger and demonstrate that refilling mechanism operates properly.
Project Risk
Inherent Overheating Motors Battery Failure
Implementation Probability of microcontroller failing
(prototyping) Timing Circuit RFID Interference
Risk 1: Timing Circuit
Probability (Likelihood)
1
0Consequence
Performance
Cost
Schedule
Potential Degradation
Sys Reqt not Achieved
Element Increase > 50%
System Increase > 40%Element Increase
Increase >10%
x
x
x
x
High Risk – Severe disruption expected to performance, cost, and / or schedule even with risk mitigation plans in place.
Moderate Risk –Expected disruption to performance, cost, and / or schedule can be overcome by implementing risk mitigation plans.
Low Risk – Little disruption expected to performance, cost, and / or schedule.
Mitigation of the Timing Circuit
Double checking the code Testing the code before finalizing the
feeder
Risk 2: RFID
Probability (Likelihood)
1
0Consequence
Performance
Cost
Schedule
Potential Degradation
Sys Reqt not Achieved
Element Increase > 50%
System Increase > 40%Element Increase
Increase >10%
x
x
x
x
High Risk – Severe disruption expected to performance, cost, and / or schedule even with risk mitigation plans in place.
Moderate Risk –Expected disruption to performance, cost, and / or schedule can be overcome by implementing risk mitigation plans.
Low Risk – Little disruption expected to performance, cost, and / or schedule.
Mitigation of RFID Interference
Testing of Multiple RFID tags Range of the tags Interference
Project Schedule
Bill of Materials
Review Action Items