Environmental ADC Interface P Team Members

Transcription

1 Environmental ADC Interface P14346 Team Members Caleb Stephens- Electrical Engineer Kevin Oswald- Electrical Engineer Ory Maimon- Electrical Engineer Edward Wlodarczyk- Electrical Engineer Marissa Fox- Electrical Engineer Zeeshan Amin- Electrical Engineer

2 Agenda Project Description Customer/Engineering Requirements Final Design Concept/System Architecture Test Results Summary Future Improvements & Expansion Conclusion

3 Project Description Current State Currently, engineering students oversimplify the Analog-to-Digital Converters (ADC) design primarily because of factors such as inexperience, lack of evaluation boards, and unrecognized electronic ability in various environments. Project Goals The goal of the Environmental Analog-to-Digital Interface evaluation system are to create a test fixture for RIT engineering students in Senior Design and EEEE-420. The interface will allow the student to analyze the error between analog and digital conversion. This evaluation system will contain: Four to eight analog sensors Three different ADCs A relevant microcontroller that will interface with a PC. Learning module Theory versus Design text material

4 Customer and Engineering Requirements Customer Requirements Evaluation System with 4-8 Sensors -CMOS thermistor -Infrared emitter & detector -Thermcouple -Strain gage -Accelerometer -Gyroscope ADC Interacts with different sensors -MATLAB interface -Hardware interface Processing Scheme for each Sensor Engineering Requirements -Amplification minimum ~1.0v PC and ADC communication -SPI -Serial -Parallel ADC Performance Comparison -ADC Theory versus Design text material -Continuous (oscilliscope) & Discrete (MATLAB) signal Specification & Coding support -Code Commenting -User Manual Learning Module -Practicals -Sensors & Power -ADCs Reliability - Test Plans - Intuitive Design - Extensive Resources Fast Prototyping - Single, Dual & Triple Analog Inputs - 1.8v, 3.3v & 5.0v Power Supply - Control Switches (ON/OFF power, ADC select, sensor select)

5 Final Design Concept

6 Sensor, Switch and Power Architecture Overview Sensors Power Switch

7 Sensor Architecture Gyroscope & Accelerometer -Internal Amp & Filter Strain Gauge -Half Wheatstone Bridge -Amp Infrared -Basic circuit (resistors) CMOS Thermal & Thermocouple (type k) -Celsuis and Farenheit -Amp (thermocouple) -Isolated from circuit Additional Sensor Slot 500mA

8 Switch Architecture Binary Input Power 000 Single Dual 5.0v 010 Triple 5.0v 011 Triple 5.0v 100 Single 3.3v 101 Single 5.0v Dip Switch controls 8:1 and dual 4:1 muxes 8:1 mux controls first signal of each sensor The 4:1 mux controls secondary and tertiary signal 110 Single 3.3v 111 Single 3.3v

9 Power Supply Architecture TDK Lambda power supply 3.0A 2 Boosts (NCP1402) 3.3 V source to 5V Linear regulator (LD1117) 3.3V source to 1.8 V I total = 200mA mA + [400μA + 100mA + 50mA 2 ] = 1.40A 3.0A

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11 Analog-to-Digital Converters TYPE RESOLUTION [BITS] CONVERSION SPEED (MAX) [KSPS] SAR (INTERNAL) SAR PARALLEL PIPELINED PARALLEL PIPELINED DELTA-SIGMA DELTA-SIGMA

12 Microcontroller MSP 430 Tiva C (ARM Cortex M4F) Frequency 16 MHz 120 MHz FLASH Memory 16 KB 1025 KB (1 MB) RAM 512 B 256 KB Interface Channels 1 I2C 10 I2C 2 SPI 4 Quad-SSI 1 UART 8 UART Internal ADC 8ch 10 bit ADC Two 12-bit ADCs with max sample rate of 2Msps Tiva TM4C1294NCPDT

13 PCB Design Control

14 Software Architecture

15 Learning Modules Created using GUIDE in MATLAB Learning Modules contain datasheets for the sensors and ADCs Supplemental questions provided in a word document Practical 1 Sensors Power Supply Switches Practical 2 Successive Approximation Register (SAR) Data Sheets Practical 3 Parallel Pipeline Data Sheets Practical 4 Sigma Delta Data Sheets

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17 Summary of Test Results The top plot is the capture from the oscilloscope Bottom two plots are MATLAB after sampling. Components: -Gyroscope 5.0v supply Not Moving -Internal SAR 1.25kHz 12-Bit Test One: Capture signal at rest & DC.

18 Summary of Test Results The top plot is the capture from the oscilloscope Bottom two plots are MATLAB after sampling. Components: -Gyroscope 5.0v supply Moved periodically -Internal SAR 1.25kHz 12-Bit Test Two: Capture periodic signal. -It s important to note that the gyroscope was manually moved, which accounts for the fluctuations in signal.

19 Summary of Test Results DC Specifications Offset Error -Deviation of transition points Gain Error -Deviation from ideal slope Differential Nonlinearity (DNL) -Deviation of code from 1 LSB Integral Nonlinearity (INL) -Overall deviation from linear response From DC plot, notice that noise is sampled correctly, but we cannot tell how much noise is introduced by the ADC. Also, DNL and INL cannot be found due to too much noise in signal. AC Specifications Signal-to-Noise Ratio (SNR) -Noise present due to quantization error SNR plus Distortion -Includes effect of all noise, distortion, and harmonics from ADC. Effective Number of Bits (ENOB) - How many bits are accurate

20 Technical Documentation Functionality Report Detailed explanation of each ADC type Technical Paper Covers design stages Comparison of different ADC types Interface Comparison (SPI, I2C, Serial, Parallel)

21 Future Improvements & Expansion 1. Explore the use of DSP for Digital Data capturing and analysis 2. Use of LabView for analog signal capturing from the oscilloscope 3. Incorporate very high frequency signals (audio signals or sonar sensor) to better evaluate different ADC parameters (push their limits) 4. Differential inputs 5. Variable Voltage source for more flexible ADC voltage reference 6. Evaluate I2C interface along with SPI 7. Include basic flash ADC (example 4 bit very low sample rate)

22 QUESTIONS/ FEEDBACK