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ECE 477 Design Review Team 4 - Spring 2012

ECE 477 Design Review Team 4 - Spring 2012. Brandon Davis, Ryan Rhodes, Stephen Zabrecky, Danny Hudepohl. Outline. Project overview Project-Specific Success Criteria (PSSC) Block Diagram Component Selection Rationale Packaging Design Schematic and Theory of Operation

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ECE 477 Design Review Team 4 - Spring 2012

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  1. ECE 477 Design ReviewTeam 4 - Spring 2012 • Brandon Davis, Ryan Rhodes, Stephen Zabrecky, Danny Hudepohl

  2. Outline • Project overview • Project-Specific Success Criteria (PSSC) • Block Diagram • Component Selection Rationale • Packaging Design • Schematic and Theory of Operation • Software Design / Development Status • Project Completion Timeline

  3. Project Overview • Creates a variety of water-based drinks from powders stored in the device. • Two holding tanks for storage of multiple beverages. • Device can self-clean, so solution cross contamination is eliminated.

  4. Project Specific Success Criteria (PSSC)

  5. IR IN x 4 IR IN x 4 Force x4 RTD x4 Valve x18 RPG Desktop/Laptop w/ Bluetooth Block Diagram 12V 3.3V 18 3.3V PIC32MX µCtrl I/O LCD 3.3V 2 UART 3.3V 4 AtoD 3.3V Thermoelectric Peltier 2 I/O 4 AtoD 3.3V RPG 3 I/O 4 AtoD 3.3V VCC 2 UART RN-41 Bluetooth GND 3.3V 12V 5V 3.3V VCC Buck Converter Linear Regulator GND

  6. Component Selection RationaleValves • Low Current Valves: Water Flow, Powder Dispensing • 0-3psig Gravity Feed • 1/2” ID Tube Barb Inlet and Outlet • 0.5A Coil Current • High Current Valves: Heating & Cooling Selection • 0-160psig Gravity Feed • 3/8” FNPT Inlet and Outlet • 1.5A Coil Current

  7. Component Selection RationalPump • Brushless DC 12v - 13W, 1.1A • 5m Head, 7.1psig • Approximately 3 GPM Flow Rate 7

  8. Component Selection RationalElectronics • PIC32 Microprocessor • Lots of GPIO’s • 3 UART’s • 16 ATD’s • Power MOSFET • Low Rds(on) • 5A Without Heat Sink • Peltier • 25 Watts Heating/Cooling Power (2-6A) • Attaches to Water Block Heat Exchanger 8

  9. Component Selection RationalElectronics • H-Bridge IC • 6A Output Without Heat Sink • Bi-Directional Control, for Heat and Cool Selection • Force Sensor • Range: 100g - 10kg • RTD (Temperature Sensor) • Pt100 - 100 Ohm’s @ 0°C • Range: -50°C - 250°C 9

  10. Package Design Considerations • Gravity fed solution management • Low center of gravity • FDA approved containers and sealants • Protecting the Electronics • Ideally NEMA 4X or IP68 • RadioShack enclosure

  11. Package Dimensions 80/20 1” x 1” Extruded Aluminum Front View Side View 16” Top Slices (Shelves) 36” 10.5” 36” 16” 36” 16” 18” 18” 16” 36” 20” 12” 12” 12” 16” 36” 10.5”

  12. Package Layout Powder Containment Front View Electronics 36” 10.56” 36” 16” Mix Tank 36” Holding Tanks (2) 20” Heating/Cooling System 36” 10.56” Spigot

  13. Design Schematic & Theory of Operation Buck Converter Solenoid Valves IR RX/TX Micro Peltier Control Bluetooth Module RJ12 LCD/RPG (need to add) Linear Regulator RTD Sensors Weight Sensors

  14. PIC32MX340F128H Microcontroller Features: • 64 pins • 128 KB Flash & 32 KB RAM • 14/16 ATD pins used • 2/4 UART used • 26 I/O pins used • 14 unused pins • RJ12 for programming

  15. Solenoid Valves • Regulates the Flow of Water • 18 Solenoid Blocks used • Two were changed to mixing motors • Consists of • Terminal Block • DS14002 Surge Protection Diode • FDP5800 Power MOSFET

  16. Power • LM2575 Buck Converter • Converts 12V to 5V • In recommended configuration • LM 3940 Linear Regulator • Converts 5V to 3.3V • In recommended configuration • H-bridge • Powers the Peltier for heating and cooling • Design is changed

  17. Bluetooth RN-41-DS • Connected via UART RX/TX pins • In constant communication with the computer, will send data every second • Will transmit sensor statistics and receive mixing instructions • Because of soldering concerns, we decided upon using a breakout board

  18. Sensors • All sensors will use ATD pins • 4 IR Detectors • Will use 2 of each circuit shown on the right • Detects powder tank levels • 4 RTD Sensors • Detects holding tank temperature • 4 Weight Sensors • Detects holding tank water levels

  19. PCB Layout: Design Constraints • Microcontroller pin-out and implications for PCB layout • Power rail concerns (EMI emission, trace size) • Board size isn’t significant factor. Max approximately 12”x11”. Shouldn’t need that much space.

  20. PCB Board: Pinout Solenoids/Pumps Misc I/O Misc I/O Bluetooth Sensors LCD Figure 2.) PIC32MX3XX Pinout

  21. PCB Layout: Board Layout Figure 2.) Drinkmaster 8000 PCB layout

  22. PCB Layout: Microcontroller • Considerations • Large number of Ports used (location important) • Decoupling/Bypass Capacitors (8 total) • Dip Switch for Debug/Reset/ETC • Debug/In-circuit programming RJ12 jack Pic32 DIP Switch Figure 3.) PIC32MX Micro and Immediate peripherals

  23. PCB Layout: Power Supply • Considerations: • Need a large 12V supply and ground rail for Solenoids and Peltier • Need large traces • Expecting 16 valves * 0.5 A * 12 V + 2 valves * 1.5 A * 12V + 2 pumps * 1.5 A * 12V = 168 W on top edge 12V rail • Expecting 6A * 12V = 72 W for Peltier supply • Need to supply 3.3V to the other side of the board • Having one ground could result in large ground current loops (ground becomes an antenna). Unacceptable amount of EMI for FCC/reliability reasons. • See next slide for solution Figure 4.) Power Supply

  24. PCB Layout: Revised Power Rail • Solution: • Have a 12V Trace (200 mil) on top of board at “north” edge and similar size trace on “east” of board • Large Ground Plane across middle of most of the board • Need to minimize EMI for FCC/reliability reasons. Isolate main ground from 12V ground loops where possible (single point of contact). Figure 4.) Power Rails

  25. Software Design / Development Status • Platform of Choice: Mac OS X + Objective C • Backup Platform: Visual Basic on Windows • Transmitting serial data with Bluetooth module is the biggest hurdle to software success. • Implementation is straightforward but hard to test without chip

  26. Software Design / Development Status

  27. Software Design / Development Status

  28. Software Design / Development Status

  29. Project Completion Timeline

  30. Questions/Comments?

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