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Microprocessor based Design for Biomedical Applications MBE 3 – MDBA XI : Project Outlooks. Resumee of our Project Works (1) We built 4 AVR Evaluation Board Kits and used them for basic firmware projects with the ATmega8 : ● AVR-GCC, make, AVRStudio toolchains
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Microprocessor based Design for Biomedical ApplicationsMBE 3 – MDBAXI :Project Outlooks
We built 4 AVR Evaluation Board Kits and used
them for basic firmware projects with the ATmega8 :
●AVR-GCC, make, AVRStudio toolchains
● Firmware download via direct SPI access
● GPIO, Timer Interrupts, ISRs
● UART, Interrupt driven communication
● Analog/Digital Conversion
● Transfer of multiple channels, data packets
We brought up 4 Monolith-EEGs :
●soldered and debugged the SMD-boards
● soldered the extension boards with SPI connectors
● understood the analog and digtial schematics (nearly ;-)
● ported the firmware to the ATmega168
● used the FTDI UART-USB converter ICs
● investigated the bootloader-mechansim
● evaluated our designs with realtime EEG / ECG recordings
We did a great job !
Here come a few ideas ….
● an EEPROMto store configuration data
● battery driven (offline) operation:
what batteries / accus ? Stepup converter ?
● wireless communication: add a bluetooth or zigbee module
● on-board data-logging: interface with a MMD / SD memory card
● new sensors: GSR/EDA , temperature, pulse, acceleration ..
● evaluate active (dry) electrodes and alternative electrode caps
Miso: master in slave out
Mosi: master out slave in
SS: slave select
SDA : serial Data
SCL : serial Clock
R1, R2 : Pullup Resistors on the Bus lines, devices tri-state their outputs
line level goes low if any of the connected device outputs 0
START: SDA goes low during SCL high
STOP: SDA goes high during SCL high
●only two Bus Lines needed for bidirectional communication
● Master and Slave Operation
●Device can Operate as Transmitter or Receiver
●7-bit Address Space Allows up to 128 Different Slave Addresses
●Multi-master Arbitration Support
●Up to 400 kHz Data Transfer Speed
●Noise Suppression Circuitry Rejects Spikes on Bus Lines
●Wake-up when AVR is in sleep mode and slave address detected
as ever: the AVR datasheet has the details …
at the uC (firmware) side:
● on-board filtering ( configure FIR / IIR filters for channels )
● on-board feature extraction ( pulse rate ? )
● Bidirectional communication :
change baud- and sampling rate at runtime
select relevant channels
allow access to I/O-pins ( Events ? ERP-recording ? )
error detection / correction for data transfer
… some of these features are already present in the p21-firmware:
at the PC (host) side:
● write our own data packet parser
● write a simple biosignal tracing and recording software in a
platform independent environment
(JAVA? C++ & GTK / QT / SDL ?)
● investigate algorithms for feature extraction
(pattern recognition ? LDA / AR-Filter for SSVEP or μ -BCI ?)
● design Biosignal protocols with midi / optical feedback
Alpha / Theta Training ? REM-Detection ?
Muscle Rehabilitation Training ?
Extend / improve the software:
● add new modules
● remove OS-dependent parts
● improve signal handling …
● This project has lots of potential for future improvements
● in the optimal case, Open Source Projects are a win-win situation
I hope you enjoyed the show -
have a good time and much Alpha-Activity !