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Workout Buddy A muscle fiber stimulation sensor and data logger Senior Design Group 8 Summer 2009

Workout Buddy A muscle fiber stimulation sensor and data logger Senior Design Group 8 Summer 2009 Matt McNealy (EE) Scott Martin (EE) Andrew Lee ( CpE ) Josh Hamby (EE). Goals & Objectives.

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Workout Buddy A muscle fiber stimulation sensor and data logger Senior Design Group 8 Summer 2009

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  1. Workout Buddy A muscle fiber stimulation sensor and data logger Senior Design Group 8 Summer 2009 Matt McNealy (EE) Scott Martin (EE) Andrew Lee (CpE) Josh Hamby (EE)

  2. Goals & Objectives • To design and implement a device that will allow weight lifters to monitor and track their progress electronically. • To build a sensor system that: • Measures the electric potential generated by certain muscle groups. • Detects the angle of body part being exercised. • To learn about wireless technology, medical devices and programming microcontrollers. • To find points of over exertion in any particular exercise and improve on underworked muscle groups.

  3. Specifications and Requirements • Control module: • Operating time: 3 hours. • Operating voltage: 3.3V • Powered by a 9V lithium battery. • Dimensions: 3” x 2.6” • Wirelessly receive data from the sensor circuit. • Automatically count repetitions and sets. • Display data on the LCD screen. • Write data to a micro-SD card. • Sensor circuit: • Operating time: 3 hours. • Operating voltage: 2.8-3.7V • Powered by polymer lithium ion battery • Dimensions: 2.1” x 2.3” • Measure S-EMG ranging from 0.02-5mV. • Capability of measuring a full 360 degree range of motion in three dimensions. • Communicate with the control module up to 3 meters. • Must secure to the body via velcro strap.

  4. Block DiagramSensor Unit

  5. Block DiagramControl Module

  6. EMG & EKG Requirements Amplifier: Gain of 1000+ High CMRR >95 db for frequencies 10 – 500 Hz Input impedance = 10 x electrode impedance Skin Preparation: Cleaned and freed of dry skin cells Centered on the belly of the muscle 2 Electrodes 2 cm center to center

  7. Sensor Circuitry EMG & EKG Detection: • INA122P-ND Instrumentation Amplifier Angle Detection: • MMA7260Q Triple Axis Accelerometer

  8. Instrumentation Amplifier • INA122P-ND • Voltage supply: 2.2 - 36 VDC • Supply current: 60 - 85 μA • CMRR: 83 - 96 db • Gain: 1-10000 • Input impedance: 10^10 ohm • Digikey: $5.56 • AD626AN-ND • Voltage supply: 2.4 - 10 VDC • Supply current: 230 - 290 μA • CMRR: 66 - 90 db • Gain: 1-100 • Input impedance: 200 k ohm • Digikey: $7.46

  9. Signal Acquisition & Processing • Processing of the signal enables the user to maximize their workout experience.

  10. Triple Axis Accelerometer • MMA7260Q : • Power supply: • 2.2 - 3.7 VDC • 500 - 800 μA • Selectable sensitivity: • 1.5g = 800 mV/g • 2g = 600 mV/g • 4g = 300 mV/g • 6g = 200 mV/g • Sleep mode option • Sparkfun: $19.95

  11. MMA7260Q Orientation

  12. Testing The MMA7260Q X-axis = vertical Z-axis = horizontal X-axis = horizontal Z-axis = vertical

  13. Atmel Atmega 168 8 bit MCU running at 16 MHZ with XTAL Serial Communication via UART, I2C, SPI 6 channel 10 bit Analog to Digital Converter 3 Timers, 6 PWM channels Free C Compiler and Development Tools

  14. Analog to Digital Conversion Using highest possible Sampling Frequency 125kHz Approximate resolution is 4.9 mV The free running mode allows the control unit to continuously update the voltage received off the sensor and provide the user with a measurable output of intensity.

  15. Development Environments AVR Studio is an Integrated Development Environment for writing, compiling, simulating, and debugging AVRDUDE is an open source utility to download/upload/manipulate the ROM and EEPROM

  16. AVRlibc and AVRlib AVRlibc is the Standard C Library for AVR microcontrollers and provides basic functions like printf, stdio calls, math functions, plus some AVR-specific functions AVRLib provides functions for conventional tasks such as writing to LCD’s and SD cardsand reading from buttons and encoders

  17. Getting User Input – Rotary Encoder 3 Terminal Device to get sequential input 2 bit grey code provides 4 states for MCU to read MCU must keep track of previous state. Debouncing via software delays or hardware LPF’s Triggering via Interrupts or Polling

  18. Color LCD 128x128 Nokia Clone LCD Logic - 3.3V @ 2-3mA LED Backlight - 7V @ 40-50mA (very bright) Full 4,096 Color Display Uses the Epson S1D15G10 or Philips PCF8833 Controller Active Display Dimensions: 1.2"x1.2” Two-wire serial SPI interface (clock and data)

  19. Setting the Processor Speed The clock must be at a specific frequency in order to set the correct sampling rate to sample data from the EMG sensor. The clock value was chosen to ensure the highest sampling resolution possible that the Atmega 168 can support.

  20. User Interface

  21. Wireless Interface - TXM-900 • Specifications • Operating voltage: 2.8–13 VDC • Supply current: 14-17 mA • Transmit frequency range: • 902.62-927.62 MHZ • Data rate: 100-56,000 bps • Operating temperature range: • -30 to 85C • SIP Style Price: $29.45 from Digikey • Part #: TXM-900-HP3-PPO-ND • SMD Style Price: $29.45 from Digikey • Part #: TXM-900-HP3SPO-ND

  22. Wireless Interface - RXM-900-HP3-xxx • Specifications • Operating voltage: 2.8–13 VDC • Supply current: 16-21 mA • Receive frequency range: • 902.62-927.62 MHZ • Data rate: 100-56,000 bps • Operating temperature range: • -30 to 85C • SIP Style Price: $43.40 from Digikey • Part #: RXM-900-HP3-PPO_-ND • SMD Style Price: $39.22 from Digikey • Part #: RXM-900-HP3-SPO-ND

  23. Antenna • JJB Series • The Electrical Specifications: • Center Freq. 916MHz • Bandwidth 30MHz • Wavelength 1/4-wave • Impedance 50 ohms • Connection Direct solder Model: ANT-916-JJB-xx Price: $1.96 from Digikey

  24. Antenna • SP Series “The Splatch” • The Electrical Specifications: • Center Freq. 916MHz • Bandwidth 30MHz • Wavelength 1/4-wave • Impedance 50 ohms • Connection Surface-mount Model: ANT-916-SP Price: $2.08 from Digikey

  25. SD CARD MODULE For our data logging we based our design off of CC Dharmani’s “SD Card Interfacing with ATmega 8/32 (FAT32 implementation)” project. The circuit design and open source files were carefully adapted to work with our Atmega328p. We used his method of creating FAT32 files. More info at: http://www.dharmanitech.com/2009/01/sd-card-interfacing-with-atmega8-fat32.html

  26. SD MODULE cont.. This schematic shows the integration of the SD card module into our design. The SD card module requires 3.3-3.6v in order to write data to the micro SD card.

  27. Layout of PartsSensor Unit • Data from the accelerometer and sensor units are fed into the ATmega328p MCU. • This data is streamed to the control unit via transmitter at 9600bps. DATA

  28. Layout of Parts Control Unit • Data will be received by the receiver and fed into the ATmega328p MCU. • Data is then saved to the SD card in the FAT32 file system architecture. It will become a CSV file. (Comma-separated values) • The SD card can now be removed from the device and read on a computer . DATA DATA

  29. CSV file • The CSV file saved on the SD card can be opened and read. • The SD card will contain from each workout: • X-axis • # of repetitions • Z-axis • EMG signal • Format: 126,0,200,5, 125,0,201,5, .................... • Used to keep track of the effectiveness of the user’s workouts.

  30. CSV file (Excel) It is up to the user how he/she would like to use the data. For example, the CSV file can be easily opened using Excel and a graph can be made using the values stored. The columns are the X-Axis, Repetitions, Z-Axis and EKG signals respectively. Opening the CSV file in Excel Graphing the data in Excel

  31. Power SystemSensor Circuit • Requirements • Generate sufficient electricity to keep the unit running for 3 hours. • Environmentally friendly • Length of charge • Motivating factors: Availability, capacity

  32. Power SystemSensor Circuit • Operating Voltages • (1) MMA7260Q – 3.6V • (1) Atmel ATmega328 – 3.6V • (1) TXM-900-HP3 – 3.6V • (2) INA122 Instrumentation amplifier – 3.6V • Total Power Consumed: 360mW • CR2032 3V lithium button cell battery was used initially, but the accelerometer did not function properly due to a dropout voltage across the battery of 500mV.Minimum voltage for the accelerometer is 2.7V • Capacity: 225mAh. Radius=20mm ,height=3mm

  33. Power SystemSensor Circuit • Powered by a rechargeable 3.7V polymer lithium-ion battery. • Has a capacity of 650mAh.

  34. Sensor system

  35. Power Supply • Display module • Demands 340mA • Total power consumption of 1.112 W • Powered by the Ultra life 9V battery • Chemistry: Lithium • Capacity: 1.2 A*h • Can run the module for 4 hours before replacement is needed.

  36. Display Module

  37. Project Timeline

  38. Budgeting Fully funded by the V.A.

  39. Questions?

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