Final Presentation P14452

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Karen Johnston
5 years ago
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1 Final Presentation P14452

2 Overview MSDI Review Customer Needs Requirements Functional Decomposition Concept Selection Detailed Design MSDII Detailed Design Revisited Build Test Reflect What Remains Lessons Learned

3 MSDI Review

4 Customer Needs

5 Requirements

6 Functional Decomposition

7 Concept Selection

8 Benchmarking Device Our DAQ MSR145 MSR160 Slice Micro Total Cost ~$80 $1018 $1417 ~$7000 Number of Sensors Max Sample Rate 20,000 Hz 50 Hz 1,000 Hz 120,000 Hz 4M Samples (8GB SD) 2M Samples 2M Samples 4M Samples (8GB SD) Input Voltage 0-2.5V 0-10V 0-10V V Bit Width 16 Bit 12 Bit 12 Bit 16 Bit Capture Duration

9 Detailed Design Overview Thermal Analysis Vibration Analysis Analog Signal Processing Digital Control

10 Thermal Analysis

11 Vibration Analysis Resonant frequency of compressor found to be 6 Hz in X and Z, and 12 Hz in Y Theoretical resonant frequency of PCB calculated to be 8450 Hz

12 Analog Signal Path 2.5mm Jack MAX7403 Filter 8th order Low-pass filter Adjustable cutoff frequency MAX9939 PGA Adjustable gain factor V/V

13 Digital Control Freescale KL25Z 48 MHz 32-bit SAR ADC 16-bits 1 MSPS SPI USB

14 MSDII

15 Detailed Design Revisited Enclosure Selection Printed Circuit Board Design Microcontroller Roulette Bill of Materials

16 Enclosure Selection BEX Series 1 Aluminum Gaskets and Endcaps Flange Mounts Perfect size for PCB Needs Adapter Plate

17 PCB Design (Revision 1) Single Board Small Footprint Low Profile Freescale KL05Z Problems Missing Protection Diodes USB Backwards No Battery Connector Signal Connector Pads Incorrect Wrong SD Pads

18 PCB Design (Revision 2) Daughter Board Signal Conditioning Power microsd Problems Battery Connector Diodes Backward Power Switch Buck-Boost Enable SD Pad inverted Header Spacing

19 Microcontroller Roulette STMicro STM32F373 3 Sigma-delta ADC SD Interface $250 Dev Board TI MSP430 SAR ADC <8 MHz Clock < $5 Dev Board Cypress PSOC Analog Front-end Configurable Logic Small Input Range Freescale KL05z 48 MHz 4 KB RAM No USB $13 Dev Board MBED WINNER: Freescale KL25z 48 MHz 16 KB RAM USB $13 Dev Board MBED

20 Bill of Materials Item Quantity Cost FRDM-KL05Z 1 $12.95 BOX Exclosure 1 $10.93 PCB 1 $33 MAX7403 (LPF) 2 $3.76 ea. MAX9939 (PGA) 2 $1.68 ea. LiPo Battery 1 $1.20 Sensor Ports 2 $0.50 ea MISC ~$10 Total Cost: ~$80

21 Testing Overview Enclosure Vibration Testing PCB Testing Power Conditioning Analog Signal Path Software Testing Microcontroller Firmware DAQ Configurator

22 Enclosure Vibration Testing B & K shaker table SigLab software Accelerometer on shaker table and top of enclosure

23 Enclosure Vibration Testing Random w/o Rubber Endcaps Chirp w/o Rubber Endcaps Chirp w/ Rubber Endcaps Random w/ Rubber Endcaps

24 PCB Testing: Power The output of the boost converter is dependent on the resistors R1 and R2 The design had the resistors reversed but this was fixed

25 PCB Testing: Power The Li-po charging chip was working This is proved by the status pin being high when the battery is charging The status pin is connected to an input on the microcontroller

PCB Testing: Analog Path Sensor input from function generator 0-2 Vpp input @ 1kHz Output of PGA VOUTA = VCC/2 - Gain * (VINA+ -

26 PCB Testing: Analog Path Sensor input from function generator 0-2 Vpp 1kHz Output of PGA VOUTA = VCC/2 - Gain * (VINA+ - VINA-) + Gain * VOS VOS-INHERENT = (VOUTA VCC/2)/Gain Output of Filter Vout range 0.25V - VDD VCOM= VDD/2 VOUT = (VIN - VCOM) + VOS

27 PCB Testing: Low-pass filter Fc= 1MHz, Fout= 10Hz Fc= 1MHz, Fout= 11kHz fc = fclk / 100 Fc= 1MHz, Fout= 100Hz Fc= 900kHz, Fout= 10kHz

28 SW Testing: Firmware Completed: SD Card Read Write PWM (LPF) ADC Internal Square Wave In Progress: ADC External Signals PGA On-board 3-axis Accelerometer

29 SW Testing: Configuration Completed: File Manipulation New Save Open Exit Load / Store Settings In Progress: Generation of Standalone Executable

30 Reflect: What Remains? Mechanical Seal Enclosure Install Power Switch Analog Update PCB Design to Fix Problems Found in Testing Find replacement for PGA (Wide Input) Digital Complete Firmware Testing USB Mass Storage Documentation User Manual Developer Manual

31 Reflect: Lessons Learned Mechanical Existing enclosures are abundant Cross-Discipline knowledge is important Use intuition to validate simulation results Electrical READ Datasheets Consult Experts Design Twice, Build Once Simulate Early, Simulate Often Triple check designs before ordering

32 Reflect: Lessons Learned Computer Best Processor!= Best Solution Dev Board vs. Full Custom ADC Roulette PSOC Trap SD Cards - Not That Easy Overall Communication with Customer Frequency Expectations Get it in Writing Testing in MSDI Importance of a Prototype

33 Questions?

Project Number: P15452

Multidisciplinary Senior Design Conference Kate Gleason College of Engineering Rochester Institute of Technology Rochester, New York 14623 Project Number: P15452 DATA ACQUISITION DEVICE Kyle Smith Electrical