The Programmable Chip EEG BCI
Introduction
This Page will introduce the
PCEEG System-
The entire system is a person connected to the PCEEG & a
computer with the operating system of their choice.
The PCEEG system has a minimum of 3 Boards.
The PCEEG System Boards:
- Amplifier & Common Signal Buffer
- Analog to Digital Converter & Right Leg Driver
- Micro Controler , Isolation System & USB Port System
Amplifier & Common Signal
Buffer
Amplifier & Common Signal Buffer Board Components
If you intend to build
a PCEEG it is helpful to know how it comes together. The
electrodes are placed on a person's head or sometimes one on a earlobe
for a ground and the other on the head.
- Then the signals from
the electrodes travel to the high frequency filter this removes raido
friequency noize picked up on the electode wires.
- The instramentation
amp amplifies the difference of the two electrodes and sends that as a
driven signal to the analog to digital converter.
- The common signal
going to the instramentation amplifier goes to a buffer circuit that
drives the signal to the right leg driver shown below.
Analog to Digital Converter &
Right Leg Driver
Analog to Digital Converter & Right Leg Driver
If you intend to build
a PCEEG it is helpful to know about the Analog to Digital Converter
& Right Leg Driver board.
- The analog to digital converter changes the analog signal
from the intstramentation amplifier to a digital output
signal.
- The right leg driver circuit is where many
amplifier board circuits common signals are summed and inverted though
the Right Leg Driver circuit & sent back to the body to cancil
out common voltages. This ground point could be a ear lobe.
- Their also is a 3 Volt to 5 Volt level converter that is to
communicate between the A-D converter that outputs 3 volts digital and
the microcontroler that runs at 5 volts.
- Their is a 2 Volt refrence source that is buffered
& filtered on this board also to setup a center
voltage point for the circutry.
Micro Controler , Isolation System
& USB Port System
Micro Controler , Isolation System & USB Port System
- If you intend to build
a PCEEG it is helpful to know about the Micro Controler it
configures the analog to digital converter, and packets the output
signals.
- These digital signals will then be sent to the USB communicator.
- The Isolation System consists of optocouplers to isolate the digital logic system from the computers power supply.
- The DC-DC converter isolatest the circuits power supply from the battery power supply.
There should be more here, but I don't
know
what yet.
Made 7/09/2008
by Joshua Wojnas, the open source community, modular EEG, monolith EEG.
