Mind Control of Systems

1
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

2
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

3
Electroencephalography

• Science of recoding electric currents produced by
  human brain
• Discovered by Hans Berger in late 1920s

4
Brain waves

• Arise from cerebral cortex
• Byproduct of normal brain function
• Millions of pyramidal cells produce small
  currents as the nerve impulses change

5
Four types of waves
Alpha
Beta
Delta
Theta
6
Similar experiments

• Mind control by rats
• US Air Force flight simulator

7
Biofeedback

• Alternative method to try to interpret brain wave
  signals
• Trains individual to learn how to produce
  specific frequencies

8
Where to go now

• Acquire the means to harness EEG waves
  (Integration of Amplifier and Filter)
• Interpret signal as 1s and 0s
• Condition subject to consistently produce desired
  signal
• Interface EEG waveform to computer software
• Change the world!!!

9
Initial Design

• Differential amplifier
• Minimum gain of 10,000
• Bandwidth of 0.5 Hz to 50 Hz
• Low noise

10
Options

• Buy amplifier
• Easier
• Cost consideration
• Design amplifier
• More difficult
• More flexible

11
Amplifiers

• Brainmaster circuit
• Modified instrumentation amplifier

12
Brainmaster circuit diagram
13
Brainmaster circuit specs

• Gain 20,000
• Bandwidth 1.7 34 Hz
• Input Impedance 10 Mohms
• CMRR 100 dB

14
Instrumentation amplifier circuit diagram
15
Instrumentation amp frequency response

• Gain 20,000
• Bandwidth 0.2 Hz - high value (depends on
  gain-bandwidth product of op-amp)

16
Test

• Compare each circuit
• Modify if needed
• Decide which one to use
• Flexibility
• Cost
• Performance

17
Modified Circuit Diagram
18
Specs

• Gain 20,000 V/V
• 86 dB
• Bandwidth 1.25 - gt 1 kHz
• CMRR 102 dB

19
Output Signal
20
Frequency Response
21
BrainMaster Model Simulation Schematic
22
Simulation Results
23
Output Waveform of First Stage
24
Output Waveform Second Stage
25
Frequency Response of BrainMaster Amplifier
26
Problems with BrainMasterand 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.