Wheelchair Mounted Dog Treat Dispenser Team Members : Zainab - - PowerPoint PPT Presentation
Wheelchair Mounted Dog Treat Dispenser Team Members : Zainab Abdullahi,Adam Dost, Gage Moore, Jachan Shrestha,Robby Wignall Faculty Supervisors: Dr.Nathalia Peixoto, and Dr.Kristine Neuber 1 Overview About us Introduction Purpose and
Team Members: Zainab Abdullahi,Adam Dost, Gage Moore, Jachan Shrestha,Robby Wignall Faculty Supervisors: Dr.Nathalia Peixoto, and Dr.Kristine Neuber
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Name: Adam Dost Major: Computer Engineering Who I am: Studying Computer Engineering while actively studying the art of delegation. What I do: Senior Azure Cloud architect of the USAF Cloud1 initiative
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Name: Jachan Shrestha Major: Electrical Engineering Who I am: Electrical Engineering Senior at George Mason University. I was born and raised in Kathmandu, Nepal. What I do: Currently full time student
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Name: Zainab Abdullahi Major: Electrical Engineering Who I am: Senior Majoring in Electrical Engineering. I was born in Fairfax, Virginia and raised in Egypt What I do: Intern at Pepco Holdings Inc
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Name: Robby Wignall Major: Electrical Engineering Who I am: Pursuing second bachelor’s degree at GMU afuer receiving BS in Applied Mathematics from VCU. What I do: Intelligent Transportation Systems Project Manager for multi-million dollar projects.
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Name: Gage Moore Major: Electrical Engineering Who I am: Currently a senior studying Electrical Engineering with a minor in Computer Science, and a concentration in Computer Engineering. Employer: Patent Intern Pillsbury Winthrop Shaw Pittman LLP
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bound and accompanied by service dogs account for 0.9 percent of the U.S. population [1].
annual tests.
maximum performance!
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[11] [7] [3]
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[5] [10] [11]
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Functionality
Operational
amount of treats Input & Output
Materials
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Previously, there were four possible designs.
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555 Timer Based Design Microcontroller Based Design
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The following system model will be used to analyze the servo motor [12] Where the steady equations are: ei = iaRa + KeVm (Voltage equation) T = Torque = iaKT = Jα (Torque equation)
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The following system model will be used to analyze the servo motor [12]
eI = Applied voltage (Volts) ia = Armature current (amps) JT = Total inertia of motor armature plus load (lb-in-sec2 ) Ke = Motor voltage constant (v/rad/sec) KT = Motor torque constant (lb-in/A) La = Motor winding inductance (Henries) Ra = Armature resistance (ohms) TL = Load torque (lb-in) Vm = Motor velocity (rad/sec) α = Acceleration (rad/sec2 )
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Astable: No “stable” state; the output is a square wave with period and duty cycle determined by the values of resistors and capacitors in the circuit. Monostable: When the 555 IC’s connection to the Trigger pin goes low, the output goes high for a certain amount of time as determined by the impedance of the circuit. Bistable (Schmitt Trigger): Similar to Monostable mode, but the output will remain high until the input to the Reset pin goes low. For the treat dispenser application, Astable or Monostable operation should be used.
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Astable Operation As mentioned previously, this circuit’s output will generate a square wave with controllable frequency and duty cycle. This mode may be useful for activating a motor and dislodging treats.
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Here, the period, T, is given by the sum of the time the
(T = T_h + T_l), and T_high = 0.7 * (R1 + R2) * C1 T_low = 0.7 * R2 * C1 Duty Cycle = 100 * [T_h/(T_h + T_l)]
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Monostable Operation This operating mode gives an output that stays high for a certain amount of time afuer being
Active output time T afuer a trigger can be found by: T = 1.1 x R1 x C1 An Resistor and Capacitor pair will then be used to achieve the required T for the treat dispenser to operate.
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555 Timer Microcontroller
which will be at around 4W.
will add around 5W and the clicker activation will also draw around 5W as well.
power consumption will range from 20-30W total.
1.2A/5V Input which will draw 6W
[18].
additional LED’s and sensors each estimating to be around 5W per
the total power consumption will range from 26-36W total.
28 Dispensing Analysis
If we want the wheel to turn ⅓ of the way to dispense the treats, the distance needed to turn is given by: ⅓ * (2πr) = ⅔ * πr Therefore, Circumference of Motor Gear = C_motor = ⅔ * πr Since gears are being used as shown in the Detailed Design portion, the outer diameter will be C_motor (to the gear tips) while the inner diameter should be large enough for the gear to turn the wheel.
29 Servo Motor Timing Analysis
We can take the specified RPM for the Servo motor and figure out how long it will take to rotate around one time as: Rotation_time = RPM / 60 This Rotation_time will then be used to design the 555-timer circuit as well as the code for the microcontroller. The output from both of these designs should stay high for Rotation_time afuer an activation.
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555-Timer Circuit in Astable Operation
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555-Timer Circuit in Astable Operation - Total Current
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555-Timer Circuit in Astable Operation - Output Pin 3 Waveform
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Raspberry Pi’s are an inexpensive “off the shelf” solution that is readily available and easy to acquire. For the treat dispenser project we wanted to target all of our resources that could be acquired immediately and not need to be special ordered or made. With the small form factor (66.0mm x 30.5mm x 5.0mm) it will allow us to insert the part without causing intrusion.
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555 Timer Microcontroller 1. Use 555 timer to generate “click” sound 2. Use small output speaker 1. Use recorded “click” sound 2. Output this signal to speaker
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555 Timer Microcontroller 1. Use time delay via capacitor to spin motor for a time constant 2. Use 555 timer to generate the driver signal for the motor 3. Reset motor control unit (555 timer) by sending setting reset to high voltage 1. Use a time delay loop to generate the time delay 2. Use Raspberry Pi libraries to spin the motor the correct distance 3. Function will reset as it acts on a generated interrupt from the user pressing a switch
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Both the PCB based design, and the microcontroller will use the same functional elements to drop a treat and catch a treat.
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Separator Rotating component Hole Base
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Motor Attachment
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Driver Gear Meshing Gear
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Adjustable Plate Treat
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555 Timer Microcontroller 1. Use capacitor to generate time delay 2. Spin vibrating motor for time constant 1. Use interrupt based on user input to spin the motor 2. Vibrating motor shakes down treat
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local electronics stores like MicroCenter or
space to handle multiple work loads [20]
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Operating temperature range: 0-70 C Vcc: Min(4.5V) Max(16V) Vout: Low level output=2.5V High level output= 12.5 V Power Dissipation = (TJ (max) - TA) / θJA
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duration
circuit for reproduction
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555 Timer Microcontroller
power consumption will range from 20-30W total.*
additional LEDs and sensors each estimating to be around 5W per
the total power consumption will range from 26-36W total.* Thus, there will be about 2-3 A @ 12 Vdc. Considering a full day of 10 hours, a fairly large batty may be needed (~20 Amp-hour) Final Power Consumption to be determined during prototyping. Actual power should be much less. *P = I x V - Calculations and Logic from Slide 27
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555 Timer Microcontroller
signal that reflects the sound of the clicker.
that pushes the clicker.
recorded .wav file containing the exact click sound, and will output it to a speaker.
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Materials Properties Used in project 3D printed Cheap depending upon the type of material, color, tolerance and quality used [22]. Strong and can be printed as desired. Used widely in casing and parts. Materials like PLA and ABS are cheap and ranges from $15-$20 per kg, while Nylon and Sofu PLA are much more expensive. Could be used to case the final design of the
designs can be easily modified before the production. Plastic While Plastic casing might sound like 3D printing, there are many companies that produce plastic enclosures for electronic enclosures [23]. Enclosures are cheap ($1-$10) and can be cut or modified to fit the casing needs [24]. Tough and weather-proof. Could be used to case the final design of the project.
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Materials Properties Used in project Wood / Homemade Commonly used plywood is easily available in the nearest Home Depot and can be cut into desired shape and size even by people with no skill. Could be used to case the final design of the project. MDF are cheap and will keep the cost down. PINE could be used to add quality to the project. Metal (Aluminum) Enclosures are readily found in the market. Ductile, sofu and malleable Could be used to case the final design of the project.
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Material Properties Used in project Servos Precise movement, cheap, easily available, different size choices. Can easily be paired and controlled with Raspberry Pi or
torque at high speed (130 RPM) [25]. Controlling mechanical movement
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Width = 20 mm (approx) Length = 40mm
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https://youtu.be/PJdnMzzEzp0
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time constants
initially thought
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555 Timer Microcontroller
the servo motor using 555 timer.
size of the board.
ensure Raspberry Pi was receiving files.
ensure the functionality of the servo motor. The initial team approach will be to make one complete rotation (360 degrees)
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○ 555 Timers ○ Rotary Device ○ Switches
○ PCB Design ○ PCB Assembly ○ Microcontroller evaluation ○ Power evaluation ○ Storage Container
(3 Weeks) ○ System rotary design ○ Variable output functionality ○ Accelerometer functionality
(1 Week) ○ Placement verification
(2 Weeks) ○ Experiment #1 ○ Experiment #2
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○ Feedback Review and data review
(2 Weeks) ○ Initial Progress Report ○ Mid-Flight Report ○ Final Report
(2 Weeks) ○ Experiment #1 ○ Experiment #2
○ Demo #1 ○ Demo #2 ○ Demo #3
○ Demo #1
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[1]. CDC, “Disability Impacts All of Us Infographic | CDC,” Centers for Disease Control and Prevention, 08-Mar-2019. [Online]. Available: https://www.cdc.gov/ncbddd/disabilityandhealth/infographic-disability-impacts-all.html. [Accessed: 08-Nov-2019]. [2]K. Neuber, “Treat Dispenser Project,” presented at the ECE 492 Initial Stakeholder Meeting, Aquia 235, 12-Sep-2019. [3] J. D. Rutledge, “Animal Food and Treat Dispenser.” U.S. Patent 6,988,464 B1, issued January 24, 2006. [4] C. J. Brown, “Treat Dispenser.” U.S. Patent 2003/0057228A1, issued March 27, 2003. [5] Y. Y. Wang, “Treat Dispenser.” U.S. Patent 2013/0233246A1, issued September 12, 2013. [6] D. C. Franche, “Dog Food Dispenser.” U.S. Patent 4,176,767, issued December 4, 1979. [7] F. Depenthal, “Automatic Feeding Device.” U.S. Patent 3,782,332, issued January 4, 1974. [8] M. T. Johnson, “Pet Feeder System for a Handicapped Pet Owner.” U.S. Patent 8,479,686 B2, issued July 9, 2013. [9] W. Blaydes, “Dispensing Machine.” U.S. Patent 1,928,556, issued February 23, 1933. [10] D. E. Robinson, “Automatic Animal Feeder.” U.S. Patent June 9, 1987. [11] N. R. Lewis, “Pet Feeding System and Method of Using Same.” U.S. Patent 6,349,671 B1, Issued February 26, 2002.
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[12] A. Hughes and B. Drury, Electric Motors and Drives, 4th ed. Waltham: Elsevier. [13] K. Maclean, “Wheelchair-Mounted Dog Treat Dispenser,” Wheelchair-Mounted Dog Treat
https://www.makersmakingchange.com/project/wheelchair-mounted-dog-treat-dispenser/. [Accessed: 16-Oct-2019]. [14] Hughes, A. and Drury, B. (2019). [online] Technical.wjsco.ir. Available at: https://technical.wjsco.ir/wp-content/uploads/2017/05/ElectricMotors-and-Drives-1.pdf [Accessed 7 Nov. 2019]. [15] “555 Timer tutorial.” [Online]. Available: https://www.jameco.com/Jameco/workshop/TechTip/555-timer-tutorial.html. [Accessed: 08-Nov-2019]. [16] A. Industries, “Continuous Rotation Micro Servo.” [Online]. Available: https://www.adafruit.com/product/2442. [Accessed: 08-Nov-2019]. [17] “How does a Gumball Machine work?,” YouTube. [Online]. Available: https://www.youtube.com/watch?v=Q3ZeUNDg4fQ&t=1s. [Accessed: 08-Nov-2019]. [17] [18] “PiBakery - The blocks based, easy to use setup tool for Raspberry Pi.” [Online]. Available: https://www.pibakery.org/. [Accessed: 08-Nov-2019].
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[19] “RPi GPIO Code Samples - eLinux.org.” [Online]. Available: https://elinux.org/RPi_GPIO_Code_Samples. [Accessed: 08-Nov-2019]. [20] “RPI-030 Pi Supply | Development Boards, Kits, Programmers | DigiKey.” [Online]. Available: https://www.digikey.com/products/en?mpart=RPI-030&v=1910. [Accessed: 08-Nov-2019]. [21] “NA555 Precision Timers | TI.com.” [Online]. Available: http://www.ti.com/product/NA555/toolssofuware. [Accessed: 08-Nov-2019]. [22] “The Essential Guide to Food Safe 3D Printing | Formlabs.” [Online]. Available: https://formlabs.com/blog/guide-to-food-safe-3d-printing/. [Accessed: 08-Nov-2019]. [23] D. Patnaikuni “A Comparative Study of Arduino, Raspberry Pi and ESP8266 as IoT Development Board.” ppppppInternational Journal of Advanced Research in Computer Science, vol. 8, no. . 0976-5697, May 2017. [24] “Scalable clusters make HPC R&D easy as Raspberry Pi.” [Online]. Available: https://www.lanl.gov/discover/news-release-archive/2017/November/1113-raspberry-pi.php. [Accessed: 22-Oct-2019]. [25] Continuous Rotation Micro Servo [FS90R] ID: 2442 - $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits.” [Online]. Available: https://www.adafruit.com/product/2442?gclid=Cj0KCQjw0brtBRDOARIsANMDykZM_o-SLs9Gf7AtLB_AFkEGiJs20nI Dk34L36z1GMfcGGiof2Btzl0aAvcYEALw_wcB. [Accessed: 22-Oct-2019]. [26] “Linear Solenoid Actuator Theory and Tutorial,” Basic Electronics Tutorials, 15-Feb-2018. [Online]. Available:
https://www.electronics-tutorials.ws/io/io_6.html. [Accessed: 19-Nov-2019].] 74
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