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STAFF Greg Carlsson, BSEE Rich Dehnel, BSEE Michael Host, BSEE Dave Jasinski, BSEE

318-355 Spring 2003, Team #3. CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER. STAFF Greg Carlsson, BSEE Rich Dehnel, BSEE Michael Host, BSEE Dave Jasinski, BSEE Kentucky Pommerening, BSEE Jarrod Widmann, BSEE AND BSCS. 318-355 Spring 2003, Team #3. Page 2.

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STAFF Greg Carlsson, BSEE Rich Dehnel, BSEE Michael Host, BSEE Dave Jasinski, BSEE

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  1. 318-355 Spring 2003, Team #3 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER • STAFF • Greg Carlsson, BSEE • Rich Dehnel, BSEE • Michael Host, BSEE • Dave Jasinski, BSEE • Kentucky Pommerening, BSEE • Jarrod Widmann, BSEE AND BSCS

  2. 318-355 Spring 2003, Team #3 Page 2 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Project Abstract • Precision AC motor control is currently an expensive option requiring a $200+ encoder and supporting circuitry. This project aims to design a cost effective alternative with a flexible interface which can be implemented in nearly any industrial AC motor application to provide closed-loop control. • Cost, reliability, accuracy, and safety are key aspects in the scope of this project.

  3. 318-355 Spring 2003, Team #3 Page 3 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Product Description • The input to the Closed Loop Motor Speed Sensor and Controller will be generated by an optical interrupting device which detects the shaft speed of a motor. • The input signal will be sent to a microprocessor which compares the input signal to a pre-programmed reference value. • This value will then be manipulated in the digital domain to provide an analog feedback signal to the motor controller. • A user interface is used to enter the reference value to the micro and display the actual motor shaft speed. • A power supply is used to supply the various circuits.

  4. 318-355 Spring 2003, Team #3 Page 4 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Product Feature Set • The desired features for our product included: • Accurate control of desired speed level • Analog output of 0-10VDC or 4-20mA. This signal will be used as a control signal to an AC motor drive, or as a monitor signal to a chart recorder or data logger. • Instantaneous under/over speed indicator • Programmable scaling factor for display output • Constantly displayed set-point and actual speed values.

  5. 318-355 Spring 2003, Team #3 Page 5 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Target Market • This product is being developed for use in industrial environments that require precision speed control of an AC induction motor. A variable frequency drive containing an analog input of 0-10 VDC or 4-20 mA should be controlling the motor. • An alternative application of this device is for data logging an application containing a rotating machine. • The prototype design is geared toward the North American market (120 VAC, 60 Hz), but can easily be adapted to conform to other electrical power systems throughout the world.

  6. 318-355 Spring 2003, Team #3 Page 6 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Team Page (1) • Greg Carlsson • Expertise: Audio Systems, hardware design, audio op-amp implementation • Experience: 3 years at Audio Video Specialties • Rich Dehnel • Expertise: Control & integration, building electrical systems layout • Experience: 12 years at Grande Cheese, 2 years at Lang Associates • Michael Host • Expertise: HW, board layout,VHDL,digital design, product troubleshooting • Experience: 1.5 Years at Rockwell Automation, Quality Systems Engineering

  7. 318-355 Spring 2003, Team #3 Page 7 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Team Page (2) • Dave Jasinski • Expertise: Quality control, reliability, product safety & manufacturing processes • Experience: 22+ years in electronics manufacturing, currently employed at Rockwell Automation. • Kentucky Pommerening • Expertise: Hardware design, board layout, compliance testing • Experience: 1 year internship at ABB – Research and Development • Jarrod Widmann • Expertise: Software, embedded systems & digital design • Experience: Three co-op sessions at Hamilton Sundstrand Aerospace

  8. 318-355 Spring 2003, Team #3 Page 8 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Team Logistics • Due to the fact that two members are part-time students, the team met primarily on weekends, mostly Sunday afternoons. Action items were assigned, ideas exchanged, and questions were discussed and resolved. • Emails were constantly being exchanged between members to share information. • Each team member dedicated about 8 hours per week to this project. • Responsibilities were assigned as follows: • Website Manager: Greg Carlsson • Project Archiver: Rich Dehnel • Presentation Manager: Dave Jasinski • Report Managers: Mike Host and Kentucky Pommenering • Financial Manager: Jarrod Widmann

  9. 318-355 Spring 2003, Team #3 Page 9 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Product Performance Requirements • 0.4% accuracy – actual versus displayed speed of motor shaft • Less than 4.0W power consumption • User interface keypad chosen for industrial environment • The user display will be viewable from five feet • Under-speed and over-speed indicators on user interface • Over-current and over-voltage protection on input power • Shaft speeds to 1800 RPM • Compatibility with AC motor drives and PLCs containing analog inputs. • Operable in environments from 0 – 50ºC • Mounting by DIN rail or panel screws. • Installation with basic hand tools.

  10. 318-355 Spring 2003, Team #3 Page 10 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Product Standard Requirements

  11. 318-355 Spring 2003, Team #3 Page 11 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Productization Aspects & Requirement • Health & Safety Aspects & Requirement • This product is designed for an industrial installation, therefore operational aspects were created for the industrial user. • Proper fusing and over-voltage protection are incorporated into the power supply. • Components derated for worst-case operation limits. • Packaging is user-friendly and free of sharp edges. • All components are enclosed and non-accessible by the user. Operates well below 40ºC. • Sensor circuit is properly guarded to prevent inadvertent pinch points. • User manual contains required warnings and comprehensive installation instructions. • Compliant UL508C and CSA 22.2, standards for industrial equipment. • Environmental Aspects & Requirement • This product does have any adverse affects on the environment when operating. Upon disposal, all required state and local recycling requirements will be adhered to, along with the requirements of European Standard prEN 13965-2.

  12. 318-355 Spring 2003, Team #3 Page 12 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Productization Aspects & Requirement • Legal/Ethical Aspects & Requirement • Basic operator’s manual including usage and troubleshooting instructions will be included. • Manual printed to be printed in multiple languages per Marketing requirements. • Includes UL and warning labeling. • Labeling on product in English for all user interfaces. • Warranty: one year • No known liabilities regarding malfunctions. • Societal Aspects & Requirement • No known societal aspects • Economic Aspects & Requirement • Prototype cost came is at $262 (Target $300) • Target production cost is $107.77 (Target $100) • Provides cost effective alternative for users of motor encoders. • Reliability Aspects & Requirement • Reliability calculations support a five-year warranty period. • Sustaining Aspects & Requirement • Product cannot be service in field • Long term production support for any circuit design issues will be managed by a Continuation Engineering group. • Customer installation issues will be handled by Technical Service Department.

  13. 318-355 Spring 2003, Team #3 Page 13 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Design Block Diagram

  14. 318-355 Spring 2003, Team #3 Page 14 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Allocation of Standard Requirements

  15. 318-355 Spring 2003, Team #3 Page 15 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Association of Performance Requirements • In order to achieve the level of desired accuracy, greater than 12-bits of precision are required.

  16. 318-355 Spring 2003, Team #3 Page 16 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Functional Block Description Agenda • User Interface – Dave Jasinski / Mike Host • Sensor Circuit– Rich Dehnel • Microprocessor Hardware – Mike Host • Microprocessor Software – Jarrod Widmann • D to A Conversion and Signal Output – Greg Carlsson • Power Supply – Kentucky Pommerening • Integration – Dave Jasinski Let’s start out with the user interface . . .

  17. 318-355 Spring 2003, Team #3 Page 17 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER USER INTERFACE DETAILS

  18. 318-355 Spring 2003, Team #3 Page 18 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER USER INTERFACE BLOCK OVERVIEW • The user interface will contain a 16-key keypad to enter the reference value, up-down arrow, and start/stop command. It will also contain a 4 x 20 LCD display. • The outputs include: • Connection points to the start/stop inputs of the motor drive • Start/Signal also sent to microprocessor • 4-bit reference value to micro • Comm/Enable signal to micro

  19. 318-355 Spring 2003, Team #3 Page 19 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Standard Requirements

  20. 318-355 Spring 2003, Team #3 Page 20 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Performance Requirements LCD Operating Values: [Crystalfontz CFAH2002A-TMC] Logic Supply Voltage Range: 4.5-5.5V LCD Supply Voltage Range: 4.2-4.8V Input High Voltage VIH: 2.2-5V Input Low Voltage VIL: 0.6V Output High Voltage VOH: 2.4V Output Low Voltage VOL: 0.4V Max. Input Current IDD: 1.2mA Temp. (Operating) TOPR: 0°C - 50°C Temp. (Storage) TSTG: -10°C - 60°C Viewable from 5 ft. PLD Values (TA=25°C) : [Mach 4 64/32-15JC (CMOS)] Supply Voltage Range VCC: 4.75-5.25V Output Voltage Range VOUT: 4.5-6.5V Latchup Current: 200 mA Temp. (Operating) TOPR: 0 - 70°C (Storage) TSTG: -65 °C - 150 °C DC Input voltage: -0.5V to 5.75V Input High Voltage VIH: 2V Input Low Voltage VIL: 0.8V Output High Voltage VOH: 2.4-3.3V Output Low Voltage VOL: 0.5V Keypad Operating Values: [Grayhill 96-BB2-006-R] Insulation Resistance: > 1012 at 500V Max. Output Current IOUT: 5mA for .5 seconds Temp. (Operating) TOPR: -30°C - 80 °C Temp. (Storage) TSTG: 150°C Contact Bounce: < 12mS Frequency: 66.2dB

  21. 318-355 Spring 2003, Team #3 Page 21 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Block Diagrams

  22. 318-355 Spring 2003, Team #3 Page 22 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Productization Requirements • User Controls: • 16-button keypad: Digits 0-9, enter, backspace, up/down arrows, and Start/Stop. • Safety Features: • Illuminated display indicates voltage present • Temperature range as specified by overall product • Components to be chosen to comply with temperature requirements • Hand Assembly: • Keypad and LCD display manually assembled, all other components can be automatically installed. • Societal/legal/Monetary Aspects: • Pushbuttons to ergonomically friendly • Material Degradation • Rust and corrosion • Suitable for industrial conditions • Disposability/Recycleability: • Parts recyclable as PCB assembly • Reliability: • Prototype: length of project • Production: 1 year @ 1%, 5 years @ 5%

  23. 318-355 Spring 2003, Team #3 Page 23 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Keypad Schematic

  24. 318-355 Spring 2003, Team #3 Page 24 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Keypad Schematic ENCODES TO BINARY 5 1 0 1 0 SQ WAVE OUT

  25. 318-355 Spring 2003, Team #3 Page 25 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Display Schematic • LCD display has an embedded HD44780 compatible controller.

  26. 318-355 Spring 2003, Team #3 Page 26 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Keypad Circuit Prototypes • The initial prototype unit was built on perf board with individual discrete parts. The output was set-up with an output terminal dedicated to each switch. This idea was scrapped in lieu of a pre-package 4 x 4 keypad. < Original Design _ ___ New Design >

  27. 318-355 Spring 2003, Team #3 Page 27 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Design Details • The Lattice ispDesignExpert PLD programming tool was used to develop the program used to encode the keypad data. • Due to the matrix design of the keypad, the decoder had to be designed in such a way that each row and column is constantly scanned.

  28. 318-355 Spring 2003, Team #3 Page 28 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER State Diagram for PLD Programming • The state diagram shown here was used to guide the programming of the device.

  29. 318-355 Spring 2003, Team #3 Page 29 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Timing Analysis and Validation of PLD Program

  30. 318-355 Spring 2003, Team #3 Page 30 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Lattice Design Schematic for PLD Program

  31. 318-355 Spring 2003, Team #3 Page 31 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Worst Case Analysis • Worst Case Analysis: Timing analysis for user interface and microprocessor circuit will be detailed in Microprocessor Hardware section. Mass Production Aspects • The user interface will consists of three assembly sections: • LCD Display: Manually installed on front of enclosure, interconnected with flat cable. • Keypad: Manually installed on front of enclosure, interconnected with flat cable. • Encoder Circuitry: Located on main PCB. Components to be SMT, automatically installed.

  32. 318-355 Spring 2003, Team #3 Page 32 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Parts List • Prototype parts • Mass production parts

  33. 318-355 Spring 2003, Team #3 Page 33 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Validation Plan and Results • Exercise keypad during the validation testing of the product software. • Keypad operating as expected during validation testing • Attempt to create a system anomaly when multiple keys are pressed simultaneously. • Unable to create this scenario • Verification that LCD displays proper characters and illuminates properly. • Due to programming difficulties, the LCD could not be verified. • Verify that maximum allowable debounce time is not exceeded. • Problems with the PLD code required entry of each digit individually to alleviate debounce problem. • Draws less than 750 mW • Not verified • Suitable for industrial environments • By inspection and material selection

  34. 318-355 Spring 2003, Team #3 Page 34 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Validation Results • Exercise keypad: operating as expected during validation testing • Two keys pressed: Unable to create this scenario • Due to programming difficulties, the LCD could not be verified. • Debounce time verification revealed problems with the PLD code, therefore entry of each digit was required. • Draws less than 750 mW: not verified • Suitable for industrial environments: by inspection and material selection

  35. 318-355 Spring 2003, Team #3 Page 35 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER User Interface Reliability Analysis Reliability (λss = Σ λi x FIT = xFailures/109 Hours) Overall Product Reliability Evaluation:λ = λB * πT * πV * πE * πQ  λB = Total for all blocks according to Chart, Method E πT = Total Temperature Stress Factor: for all blocks Ta = Actual Maximum Operating Temperature: 50ºC Tr = Rated Maximum Operating Temperature Tr > Ta πV = Electrical Stress Factor: for all blocks Va = Actual Maximum Operating Voltage Vr = Rated Maximum Operating Voltage Vr > Va πE = Environmental (Overall) Factor: Outdoor Stationary = 2.0 πQ = Quality (Parts and Assembly) Factor: Hand Assembly Part = 3.0 Block Reliability Values Parts per Billion

  36. 318-355 Spring 2003, Team #3 Page 36 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Let’s cover the Sensor Circuit next . . . .

  37. 318-355 Spring 2003, Team #3 Page 37 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER SENSOR CIRCUIT DETAILS

  38. 318-355 Spring 2003, Team #3 Page 38 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER SENSOR CIRCUIT OVERVIEW • Sensor Package •  Transmissive type Optical Interrupter rather than reflective: •  Reflection scatters signal •  Not as fast of a response •  Need reflective surface to be constantly clean (can’t guarantee in field) •  Square wave signal • Mounting System •  Largely aluminum – highly corrosion resistant •  Designed for this type of motor, but can be made universal •  Easily mounted and removed • Sensor Disc •  Common material – highly corrosion resistant •  Can be made with different number of holes up to 100 •  Easily machined •  Guarded – OSHA requirement • Circuit Protection •  Amperage spike •  Properly sized resistors •  Protects microprocessor and circuitry downstream • Signal Conditioning •  Schmitt trigger •  Cleans up square waves (smoothes out waveform) •  Clarifies signal for microprocessor to read/count •  Simple circuitry •  Inexpensive component

  39. 318-355 Spring 2003, Team #3 Page 39 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Standard Requirements

  40. 318-355 Spring 2003, Team #3 Page 40 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Performance Requirements Schmitt-Trigger Operating Values (TA=25°C) : Supply Voltage Range VCC: 2-6V Output Voltage Range VOUT: 0 - VCC +0.5V Input Voltage Range VIN: 0 - VCC +1.5V Power Dissipation POUT: 500mW Max. Output Current IOUT: ±25mA Max. Input Current IIN: ±0.1mA Clamp Diode Current IIK, IOK : ±20mA Current Consumption ICC: 2mA Rise and Fall Time: 500nS High Level Output VOH_MIN: 4.4V High Level Output VIH_MIN: 3.15V Low Level Input VIL_MAX: 1.35V Low Level Output VOL_MAX: 0.1V Optical Interrupter Operating Values: Supply Voltage Range VCC: 4.75-5.25V Output Voltage Range VOUT: 4.75-5.25V Max. Output Current IOUT: 16mA Temp. (Operating) TOPR: -40 to 75°C (Storage) TSTG: -40 to 85°C Power Dissipation POUT: 250mW LED Current IF: 15mA Optical Interrupter Characteristics (TA=25°C): Emitter: Value: Condition: Forward Voltage VF: 1.2 to 1.5V IF=20mA Reverse Current IR: .01 to 10μA VR=4V Receiver: Low Level Output VOL: .12 to .4V VCC=5 to 18V, IOL=16mA High Level Output VOH: 15V min. VCC=16V, RL=1KΩ Current Consumption ICC: 3.2 to 10mA VCC=16V Combination: Hysteresis: 15% typ. VCC=5 to 16V Response Frequency: 3000pps/min VCC=5 to 16V Response Delay: 3μS IF=15mA Time: 20μS IOL=16mA

  41. 318-355 Spring 2003, Team #3 Page 41 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Productization Requirements Safety: -LED Illuminated on Main Module Enclosure to detect Voltage Present -Temperature range: 0ºC - 50ºC -Components to be chosen to comply with temperature requirements -No User Controls – Limited Personal Interaction with this Block -Guarding of Rotating Disc – OSHA Requirement Ethical: - Sensor Housing and Mounting Bracket Largely Aluminum - Recycling - Potentially Dangerous Chemical Compounds: Solder and GaAs - Savings of Energy Utilizing a Drive; Energy Costs/Savings can be Calculated • Manufacturing: • - Limited Amount of Components – Hand Assembly • Possible Assembly in Other Country with lower Labor Costs • - Sensor Housing – Due to Numbering Required, May Order Pre-slotted • - Relatively Common Part – Low Overhead Storage Costs & Obsolescence Rate • Societal/legal/Monetary Aspects: • Moving parts and guarding (as required by OSHA) • - Material Degradation: • - Rust and corrosion • - Chemical resistivity/duration of exposure • - High pressure wash-down • - Suitable for industrial conditions • - Disposability/Recycleability: • - Sensor contains GaAs and solder contains lead • - Remaining parts recyclable as PCB assembly • Reliability (General): • - Prototype: Length of Project • - Production: 1 year @ 1%, 5 years @ 5% • Cost: • - Common Components – Can purchase in Large Numbers to save Money • Easily Assembled - No Complicated or Specialized Assemblies • - Sensor Housing – Easily Assembled, Common Materials • - Module Package includes varying Mounting Options Sustaining: - Long Term Production Support for any circuit design issues will be Handled by a Continuation Engineering Group - Short Term Production Support will be handled by Technical Service Department

  42. 318-355 Spring 2003, Team #3 Page 42 AC Drive Motor w/Disc Sensor Package Signal Condition Microprocessor Module Circuit Protection CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Block Diagram

  43. 318-355 Spring 2003, Team #3 Page 43 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Design Details Calculations Calculations: Resistor R1: Perforated Rotating Disc Resistor R2: 100 4.7k Transmissive Optical Interrupter Resistor R3: Square wave output to Microprocessor Schmitt-Trigger These resistor sizes were determined through calculations and used maximum current values for the individual components. No components individual current ratings were exceeded to maintain workability 1k

  44. 318-355 Spring 2003, Team #3 Page 44 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Worst Case Analysis Calculations: Resistor R1: Perforated Rotating Disc Resistor R2: 105 4.7k Transmissive Optical Interrupter Resistor R3: Square wave output to Microprocessor Schmitt-Trigger These resistor sizes were determined through calculations and used maximum current values for the individual components. No components individual current ratings were exceeded to maintain workability. 1.05k

  45. 318-355 Spring 2003, Team #3 Page 45 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Mass Production • Final assembly of the sensor circuit will be primarily hand assembly due to the mechanical nature of the design. • The discrete components will be mounted on a PC board using surface mount technology. • For mass production, the enclosure could be redesigned to eliminate any fasteners, and replace then with a snap-fit configuration.

  46. 318-355 Spring 2003, Team #3 Page 46 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Parts List • Prototype and Production

  47. 318-355 Spring 2003, Team #3 Page 47 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Validation Plan & Results (1) The first validation of this block’s working performance and the type of signal that is required to the other blocks was using Pspice, create the schematic with exact or components with similar ratings to make sure that the schematic is properly designed and therefore able to run simulations to check if the output will be acceptable to the other blocks; a 5V square wave. Pspice does not have a Transmissive Photo-Transistor is its parts library, so an optocoupler as utilized in class Project Design Lab #2 was used, because the output is similar. Below is the simulation schematic:

  48. 318-355 Spring 2003, Team #3 Page 48 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Validation Plan & Results (2) PSPICE simulation: The second validation was to run the simulation with the voltage and current blocks on the schematic in Pspice to determine if any components’ operational limits were exceeded and cause problems. Since the components are similar, a comparable simulation would be attained in the actual schematic.

  49. 318-355 Spring 2003, Team #3 Page 49 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Validation Plan & Results (3) The final validation step, after the software portion of schematic building and simulations, was to put the circuit on a breadboard and run it with the motor to be used in the final product, an oscilloscope, and a created sensor disc. A test was run at various frequencies, with the resulting waveforms below. After this test we removed the circuit from the breadboard and placed in on perforated board, wired it, and placed it in the sensor housing. This validation provided the opportunity to not only check the circuit’s stability, but the sensor housing and the method to mount it to the motor as well. < Through Schmitt Trigger > < Directly off sensor > Sensor output at 1800 RPM Sensor output at 300 RPM

  50. 318-355 Spring 2003, Team #3 Page 50 CLOSED-LOOP MOTOR SPEED SENSOR & CONTROLLER Sensor Circuit Validation Plan & Results (4) Pictures of the sensor housing during design stage. Housing is made with enough adjustability to accommodate multiple types of sensors, discs, and additional coupling methods. Achieving a method where the sensor components are attached tightly to the motor being used, easily assembled and removed, adjustable, surrounded by a stable housing that is resistant to numerous environmental factors (light, corrosion, etc), and relatively inexpensive was quite a mechanical challenge.

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