Transcript Mind Control of Systems

Mind Control of Systems
Designing a system to measure brain waves in
order to obtain commands to control the
direction of a remote-control car
By
Gary Obenski
& Jim Bradbury
Primary Goals
• Determine an efficient way to obtain brain
wave signals from human subject
• Determine a way to change different wave
patterns to commands such as ‘left’ and
‘right’
Electroencephalography
• Science of recoding electric currents
produced by human brain
• Discovered by Hans Berger in late 1920’s
Brain waves
• Arise from cerebral cortex
• Byproduct of normal brain function
• Millions of pyramidal cells produce small
currents as the nerve impulses change
Four types of waves
Alpha
Beta
Theta
Delta
Similar experiments
• Mind control by rats
• US Air Force flight simulator
Biofeedback
• Alternative method to try to interpret brain
wave signals
• Trains individual to learn how to produce
specific frequencies
Where to go now…
• Acquire the means to harness EEG waves
(Integration of Amplifier and Filter)
• Interpret signal as “1’s” and “0’s”
• Condition subject to consistently produce
desired signal
• Interface EEG waveform to computer
software
• Change the world!!!
Initial Design
• Differential amplifier
 Minimum gain of 10,000
 Bandwidth of 0.5 Hz to 50 Hz
 Low noise
Options
• Buy amplifier
 Easier
 Cost consideration
• Design amplifier
 More difficult
 More flexible
Amplifiers
• Brainmaster circuit
• Modified instrumentation amplifier
Brainmaster circuit diagram
Brainmaster circuit specs
•
•
•
•
Gain : 20,000
Bandwidth : 1.7 – 34 Hz
Input Impedance : 10 Mohms
CMRR : 100 dB
Instrumentation amplifier circuit
diagram
Instrumentation amp frequency
response
• Gain : 20,000
• Bandwidth : 0.2 Hz - high value (depends
on gain-bandwidth product of op-amp)
Test
• Compare each circuit
• Modify if needed
• Decide which one to use
 Flexibility
 Cost
 Performance
Modified Circuit Diagram
Specs
• Gain : 20,000 V/V
86 dB
• Bandwidth : 1.25 - > 1 kHz
• CMRR : 102 dB
Output Signal
Frequency Response
BrainMaster Model: Simulation
Schematic
Simulation Results
Output Waveform of First Stage
Output Waveform Second Stage
Frequency Response of
BrainMaster Amplifier
Problems with BrainMaster
and Solution
• Voltage Divider of 10000 would not register
any AC Signal
• Unable to Couple the Two Stages
SOLUTION:
Always have an alternative design it case one
goes wrong.