OpenCircuits - User contributions [en]

Techniques

2007-02-14T14:09:26Z

72.224.49.207:

== Colaberation through social bookmarking == -this involves something like del.icio.us and a webpage.

== Printed circuit board fabrication ==

=== Homebrew ===
* [[Toner Transfer]] -- This method involves laser printing your PCB design onto paper, then transferring toner onto copper-clad board.
* [[Photoetching]] -- Exposure of PCB designs onto photosensitized copper-clad board.
* [[Chemical Etchants]]

=== Commercial PCB fabrication ===
* [[Submitting PCB's for fabrication]] -- Common processes for submitting PCB's for fabrication.
* [[PCB Manufacturers]]

== Circuit construction (non PCB) ==

* [[Solderless protoboard]] ([http://en.wikipedia.org/wiki/Breadboard Wikipedia:Breadboard])
* [[Point-to-point]] ([http://en.wikipedia.org/wiki/Point-to-point_construction Wikipedia:Point-to-point construction])
* [[Wirewrap]]
* [[Dead bug style]] -- and a similar method, [http://ciphersbyritter.com/RADELECT/BREADBD/BREADBD.HTM "A Modern Breadboarding Technology: Insulating Pads Soldered to a Ground Plane"]
* [[Manhattan style]]

== Soldering techniques ==

* [[Basic soldering]] -- How to use a soldering iron.
* Surface Mount
** [[Skillet reflow]]
** [[Toaster oven reflow]]
** [[Hot air soldering]]
* [[Rework]] -- Techniques for fixing mistakes.
** [http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/302_jumper%20wires.html official NASA recommendations for adding discrete wiring ("jumper wires") to PCBs]

== software design tools ==

Some people still build circuits without ever using any software tools.
For complicated circuits, software design tools can save a lot of time.

Here we list "suites" that combine schematic capture, component editor for the components used in schematic capture, circuit simulation, PCB layout, autorouter, and footprint editor for the footprints used in PCB layout.
(Is there another place for listing stand-alone tools such as a switching power supply "wizard" and a RF analysis tool?)

Quite often people mix-and-match tools -- using a schematic capture from one suite to generate pretty schematics and a netlist, then importing the netlist a third party Specctra autorouter, then importing the result into a PCB layout program from another suite for the final manual clean-up and design rule checking.

In no particular order:

* gEDA http://geda.seul.org/ ; [http://geda.seul.org/wiki/ gEDA wiki] -- free version; open source
* McCAD EDS Lite http://mccad.com/ -- free demo version available for download, 200 pin limit
* McCAD EDS SE is free with the book [http://applefritter.com/replica "Apple I Replica Creation" ] -- supports 750 pins, 11"x17" sheet size, 6-8 data layers.

<tangent>(any useful tips in this book for those who want to build a CPU from scratch?) <reply>No, there are not. The book is more entry-level. - Tom Owad</reply></tangent>

* Protel DXP http://altium.com/ ; [http://techref.massmind.org/techref/app/protel.htm independent Protel users FAQ]
* Eagle http://cadsoftusa.com/ ; http://cadsoft.de/ ; [http://www.sparkfun.com/tutorial/PCB/eagle-output-tutorial.htm Eagle tutorial from Sparkfun] ; [http://www.makezine.com/blog/archive/2006/03/how_to_make_a_custom_library_p.html another Eagle tutorial] -- free demo version available
* DipTrace http://diptrace.com/ -- free 30 day demo version available for download.
* WinQcad http://winqcad.com/ -- free demo version (up to 499 pins) available for download

''(Should I make a huge grid here, with checkmarks for "runs on Mac", "runs under Linux", "open source", "includes autorouter", etc. ?)''
(yes!! yes you should!! now get back to work slave!!)

Another [http://techref.massmind.org/techref/pcbcads.htm list of software design tools at the Massmind].

=== Checklist for "The flow of PCB fabrication/PCB 製作流程" using Software Design Tool===
*Format and shape of PCB are conformed./底板的幾何圖形和尺寸確認
*Via size and location are conformed./定位和開孔尺寸確認
*Fixed location item are placed on suitable place./對有所要求之硬件放置的明白確認
*A one-first PCB silk layout is made./做一張1:1的PCB白油圖
*All item get enough clearance between them./所有硬件排放後檢查相鄰是否過於緊貼
*All vias get enough size to install them components./所有孔徑是否符合要求
*Make sure no worng footprint is created./肯定了腳銲盤無錯誤
*PCB is drew./完成了PCB
*Netlist is ran and got a no error result./執行netlist指令直無錯誤
*DRC is ran and got a no error result./執行DRC直至無錯誤
*Location of item is reasonable./模擬實物放置是否合理
*All items are put on to a hard copy of PCB./放置所有零件在影印本的PCB上
*Overall is checked./全面檢查確認無誤

Techniques

2007-02-14T14:08:30Z

72.224.49.207:

== Printed circuit board fabrication ==
== Colaberation through social bookmarking == -this involves something like del.icio.us and a webpage.

=== Homebrew ===
* [[Toner Transfer]] -- This method involves laser printing your PCB design onto paper, then transferring toner onto copper-clad board.
* [[Photoetching]] -- Exposure of PCB designs onto photosensitized copper-clad board.
* [[Chemical Etchants]]

=== Commercial PCB fabrication ===
* [[Submitting PCB's for fabrication]] -- Common processes for submitting PCB's for fabrication.
* [[PCB Manufacturers]]

== Circuit construction (non PCB) ==

* [[Solderless protoboard]] ([http://en.wikipedia.org/wiki/Breadboard Wikipedia:Breadboard])
* [[Point-to-point]] ([http://en.wikipedia.org/wiki/Point-to-point_construction Wikipedia:Point-to-point construction])
* [[Wirewrap]]
* [[Dead bug style]] -- and a similar method, [http://ciphersbyritter.com/RADELECT/BREADBD/BREADBD.HTM "A Modern Breadboarding Technology: Insulating Pads Soldered to a Ground Plane"]
* [[Manhattan style]]

== Soldering techniques ==

* [[Basic soldering]] -- How to use a soldering iron.
* Surface Mount
** [[Skillet reflow]]
** [[Toaster oven reflow]]
** [[Hot air soldering]]
* [[Rework]] -- Techniques for fixing mistakes.
** [http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/302_jumper%20wires.html official NASA recommendations for adding discrete wiring ("jumper wires") to PCBs]

== software design tools ==

Some people still build circuits without ever using any software tools.
For complicated circuits, software design tools can save a lot of time.

Here we list "suites" that combine schematic capture, component editor for the components used in schematic capture, circuit simulation, PCB layout, autorouter, and footprint editor for the footprints used in PCB layout.
(Is there another place for listing stand-alone tools such as a switching power supply "wizard" and a RF analysis tool?)

Quite often people mix-and-match tools -- using a schematic capture from one suite to generate pretty schematics and a netlist, then importing the netlist a third party Specctra autorouter, then importing the result into a PCB layout program from another suite for the final manual clean-up and design rule checking.

In no particular order:

* gEDA http://geda.seul.org/ ; [http://geda.seul.org/wiki/ gEDA wiki] -- free version; open source
* McCAD EDS Lite http://mccad.com/ -- free demo version available for download, 200 pin limit
* McCAD EDS SE is free with the book [http://applefritter.com/replica "Apple I Replica Creation" ] -- supports 750 pins, 11"x17" sheet size, 6-8 data layers.

<tangent>(any useful tips in this book for those who want to build a CPU from scratch?) <reply>No, there are not. The book is more entry-level. - Tom Owad</reply></tangent>

* Protel DXP http://altium.com/ ; [http://techref.massmind.org/techref/app/protel.htm independent Protel users FAQ]
* Eagle http://cadsoftusa.com/ ; http://cadsoft.de/ ; [http://www.sparkfun.com/tutorial/PCB/eagle-output-tutorial.htm Eagle tutorial from Sparkfun] ; [http://www.makezine.com/blog/archive/2006/03/how_to_make_a_custom_library_p.html another Eagle tutorial] -- free demo version available
* DipTrace http://diptrace.com/ -- free 30 day demo version available for download.
* WinQcad http://winqcad.com/ -- free demo version (up to 499 pins) available for download

''(Should I make a huge grid here, with checkmarks for "runs on Mac", "runs under Linux", "open source", "includes autorouter", etc. ?)''
(yes!! yes you should!! now get back to work slave!!)

Another [http://techref.massmind.org/techref/pcbcads.htm list of software design tools at the Massmind].

=== Checklist for "The flow of PCB fabrication/PCB 製作流程" using Software Design Tool===
*Format and shape of PCB are conformed./底板的幾何圖形和尺寸確認
*Via size and location are conformed./定位和開孔尺寸確認
*Fixed location item are placed on suitable place./對有所要求之硬件放置的明白確認
*A one-first PCB silk layout is made./做一張1:1的PCB白油圖
*All item get enough clearance between them./所有硬件排放後檢查相鄰是否過於緊貼
*All vias get enough size to install them components./所有孔徑是否符合要求
*Make sure no worng footprint is created./肯定了腳銲盤無錯誤
*PCB is drew./完成了PCB
*Netlist is ran and got a no error result./執行netlist指令直無錯誤
*DRC is ran and got a no error result./執行DRC直至無錯誤
*Location of item is reasonable./模擬實物放置是否合理
*All items are put on to a hard copy of PCB./放置所有零件在影印本的PCB上
*Overall is checked./全面檢查確認無誤

Programmable Chip EEG

2006-11-17T15:21:13Z

72.224.49.207: /* See also: */

== The Programmable Chip EEG ==
Welcome to the PCEEG Wiki, where everyone can add to this EEG brain-computer interface!

== PCEEG, What it is and why it can be the best ==
* The [http://pceeg.sourceforge.net The Programmable Chip EEG] gets its name because its hardware and software can be adjusted digitaly from a home pc.

* The hardware can be adjusted by [http://opencircuits.com/Programmable_Potentiometers Digitally Programmable Potentiometers]. They are used to set the Gain, and frequency responce.
This is usefull to calibrate multiple analog boards for different EEG tests.

* [http://pceeg.sourceforge.net The Programmable Chip EEG] is a Modular Multi-channel electroencephalograph.

* This can be used for a brain-computer interface with biofeedback using a flex sensor or servo to detect fingure movements.

* The [http://opencircuits.com/LT1168 LT1168 Programmable-Gain Precision Instrumentation Amplifier] is used to amplify the weak electric signals coming from the brain through electrodes attached to the scalp, and has internal protection circuitry for the user.

* Several matched [http://opencircuits.com/LT1114 LT1114 Low Power Precision OP-Amps] are used for amplification and filtering of the signals.

* The [http://opencircuits.com/Digitally_Programmable_Potentiometers Digitally Programmable Potentiometers AD5204] 4-Channel Digitally Controlled Potentiometer is used to make calibration of this device easier. (Historically, a weak point of homebrew designs has been their sensitivity to component value; tolerance and drift have made them require constant tweaking for good results.)

* To reduce noise in the readout of the analog part of this circuit, a common-mode feedback is passed back into the body by the driver right leg circuit. Band reject filter may also be used (to reject, for example, 60Hz noise from nearby A/C power wiring).

* The analog signal prossesing board will digitise the signal and pass the data to the control board. The control board is based on the [http://en.wikipedia.org/wiki/AVR_Butterfly AVR Butterfly] which will, further process the signals, and provide an interface to a computer & lcd display.

== Status ==
We currently have a (preliminary?) [[circuit design]] and a (prelimary) [[PCB layout]].
We are using LT switcher CAD to draw the scematic.

== Hardware Overview ==
Here is a diagram of how the analog signal processing boards and the microprocessor board will come together.
[[Image:Pceeg.jpg]]

== Description of How it Works ==
The daughter signal prossesing board is responcible for filtering and digitising the signals from the body, then the signals are passed to the control board that is the motherboard. The motherboard then can pass the signal to a larger computer.

The differential analog signal is amplified by the instramentation amplifier. Then the signal is amplified and conditioned by high pass and low pass filters.

The common mode signal is inverted summed and sent back to the body to decrese common mode signal thsi is done by the driver right leg circuit.

Band reject filters may be added soon in the future.

Then the analog signals are simultaniously digitized and the digital values can be clocked to the controler motherboard.

The controler board that is the mother board of the system and the signal prossesing daughter boards plug into is the [http://en.wikipedia.org/wiki/AVR_Butterfly AVR Butterfly]

=== How You Can Help ===
#. get the tools
== Software Tools ==
* We are using LT switcher CAD to draw the scematic. This also is a SPICE Simulator used to analize the amplifier design.
* Eagle CAD could be used in the future after all the parts are surface mount & the analog sections are alalised. To autorout future designs.
* Express PCB is being used to create the first PCB but surface mount must be used to save hole count and space.
* Maxima a computer algebra system s used for graphing and matth displays.

*I2C interface diagram for programmable resistors and a/d converters 12 or more bits with low cost.
*SPI interface diagram for programmable resistors and a/d converters 12 or more bits with low cost.
*linear switcher cad schematic drawing from PCEEG technology applied to the Open EEG design with improvements.
*migrate from switcher cad to pcb express.
*migrate from pcb express to eagle cad after testing to further development.

== Parts used in the PCEEG: ==
* [http://opencircuits.com/LT1168 LT1168 Programmable-Gain Precision Instrumentation Amplifier] is used to amplify the weak electric signals coming from the brain through electrodes attached to the scalp, etc.
* Several [http://opencircuits.com/LT1114 LT1114 Low Power Precision OP-Amps] are used for amplification and filtering of the signal
* The [http://opencircuits.com/Digitally_Programmable_Potentiometers Digitally Programmable Potentiometers AD5204] 4-Channel Digitally Controlled Potentiometer is used to make calibration of this device easier. (Historically, a weak point of homebrew designs has been their sensitivity to component value; tolerance and drift have made them require constant tweaking for good results.)

To reduce noise in the readout of the analog part of this circuit, a common-mode feedback is passed back into the body by the driver right leg circuit. Band reject filter may also be used (to reject, for example, 60Hz noise from nearby A/C power wiring).

The analog signal prossesing board will digitise the signal and pass the data to the control board. The control board is based on the [http://en.wikipedia.org/wiki/AVR_Butterfly AVR Butterfly] which will, further process the signals, and provide an interface to a computer & lcd display.

== News ==
The design is switching to EAGLE CAD, because the auto-router is excellent for open-source productivity. It will allow the design to evolve faster and with less work with a wider selection of PCB [[production houses to choose from]].

Here is a picture of the PCEEG being done in [http://www.cadsoft.de/freeware.htm EagleCAD].
[[Image:Eagle_sample.GIF]]
The eagle cad file is here [[Media:PCEEGHD.zip]]

The ideas and monkey to robot arm interface by [http://www.answers.com/topic/miguel-nicolelis Miguel Nicolelis]is very inspiring. He used implanted electrodes to monitor and allow monkeys to control a robot arm as if it was their own. Could the PCEEG do the same with its electrodes on the scalp. Only the future will show.

== Open Source Circuit Design ==
* [http://opencircuits.com/Programmable_Chip_EEG Open Source Circuit Design ]
* [http://www.thinkcycle.org/ Think Cycle]
* [http://pceegbci.blog.com/ The Programmable Chip EEG Open Source Circuit Design BLog]

== Open source (public) results! ==
PHP will be used to create a database of users and what they sample and choose to share with the open source community.

The database will give statistical analysis on users recordings.

Also the extension of SETI called BIONIC could be used as a distributed library creation of artifacts and data mining.

Please contribute and make the PCEEG a great tool for researching brain computer interfaces.

== A/D Converters ==

The programmable chip EEG needs an A/D converter to convert the analog signal (at the output of the instrumentation amplifier) into digital bits.
We expect this project to require at least 12 bit ADC.

Many Atmel and other microcontrollers have a built-in ADC, but those are at most 10 bit ADC, so that ADC is useless to us -- we are forced to use an external ADC.

What low-cost ADC are available with at least 12 bits?

* $2.50 MCP3301 has 1 ADC input (13 bits)
* $3.50 MCP3302 has 2 ADC input (13 bits)
* $3.50 MCP3204 has 4 ADC input (12 bits)
* $4 MCP3208 has 8 ADC input (12 bits)
* $8 dsPIC30F microcontroller has 8 ADC inputs (12 bits).

== The Goal ==
Eventually, kits could be sold, if there were interest.
More info is available at the PCEEG SourceForge home page at [http://pceeg.sourceforge.net/ PCEEG sourceforge.net].

----
== See also: ==
* [http://wiki.asiaquake.org/openeeg/published/ The OpenEEG wiki]

* [http://pceegbci.blog.com/ The Open EEG Brain Computer Interface BLog]

* [http://www.larryheadinstitute.com/eeg-training.html EEG Training Seminars]

* [http://pceeg.wikia.com/wiki/Main_Page wiki cities on pceeg]

* [http://pceeg.sourceforge.net pceeg.sourceforge.net]

* [http://www.answers.com/topic/miguel-nicolelis miguel nicolelis]

* [http://maxima.sourceforge.net/ Maxima - a computer algebra system]

Programmable Chip EEG

2006-11-17T15:19:13Z

72.224.49.207: /* How You Can Help */

Programmable Chip EEG

2006-11-17T15:18:52Z

72.224.49.207:

== The Programmable Chip EEG ==
Welcome to the PCEEG Wiki, where everyone can add to this EEG brain-computer interface!

== PCEEG, What it is and why it can be the best ==
* The [http://pceeg.sourceforge.net The Programmable Chip EEG] gets its name because its hardware and software can be adjusted digitaly from a home pc.

* The hardware can be adjusted by [http://opencircuits.com/Programmable_Potentiometers Digitally Programmable Potentiometers]. They are used to set the Gain, and frequency responce.
This is usefull to calibrate multiple analog boards for different EEG tests.

* [http://pceeg.sourceforge.net The Programmable Chip EEG] is a Modular Multi-channel electroencephalograph.

* This can be used for a brain-computer interface with biofeedback using a flex sensor or servo to detect fingure movements.

* The [http://opencircuits.com/LT1168 LT1168 Programmable-Gain Precision Instrumentation Amplifier] is used to amplify the weak electric signals coming from the brain through electrodes attached to the scalp, and has internal protection circuitry for the user.

* Several matched [http://opencircuits.com/LT1114 LT1114 Low Power Precision OP-Amps] are used for amplification and filtering of the signals.

* The [http://opencircuits.com/Digitally_Programmable_Potentiometers Digitally Programmable Potentiometers AD5204] 4-Channel Digitally Controlled Potentiometer is used to make calibration of this device easier. (Historically, a weak point of homebrew designs has been their sensitivity to component value; tolerance and drift have made them require constant tweaking for good results.)

* To reduce noise in the readout of the analog part of this circuit, a common-mode feedback is passed back into the body by the driver right leg circuit. Band reject filter may also be used (to reject, for example, 60Hz noise from nearby A/C power wiring).

* The analog signal prossesing board will digitise the signal and pass the data to the control board. The control board is based on the [http://en.wikipedia.org/wiki/AVR_Butterfly AVR Butterfly] which will, further process the signals, and provide an interface to a computer & lcd display.

== Status ==
We currently have a (preliminary?) [[circuit design]] and a (prelimary) [[PCB layout]].
We are using LT switcher CAD to draw the scematic.

== Hardware Overview ==
Here is a diagram of how the analog signal processing boards and the microprocessor board will come together.
[[Image:Pceeg.jpg]]

== Description of How it Works ==
The daughter signal prossesing board is responcible for filtering and digitising the signals from the body, then the signals are passed to the control board that is the motherboard. The motherboard then can pass the signal to a larger computer.

The differential analog signal is amplified by the instramentation amplifier. Then the signal is amplified and conditioned by high pass and low pass filters.

The common mode signal is inverted summed and sent back to the body to decrese common mode signal thsi is done by the driver right leg circuit.

Band reject filters may be added soon in the future.

Then the analog signals are simultaniously digitized and the digital values can be clocked to the controler motherboard.

The controler board that is the mother board of the system and the signal prossesing daughter boards plug into is the [http://en.wikipedia.org/wiki/AVR_Butterfly AVR Butterfly]

=== How You Can Help ===
#. get the tools

== News ==
The design is switching to EAGLE CAD, because the auto-router is excellent for open-source productivity. It will allow the design to evolve faster and with less work with a wider selection of PCB [[production houses to choose from]].

Here is a picture of the PCEEG being done in [http://www.cadsoft.de/freeware.htm EagleCAD].
[[Image:Eagle_sample.GIF]]
The eagle cad file is here [[Media:PCEEGHD.zip]]

The ideas and monkey to robot arm interface by [http://www.answers.com/topic/miguel-nicolelis Miguel Nicolelis]is very inspiring. He used implanted electrodes to monitor and allow monkeys to control a robot arm as if it was their own. Could the PCEEG do the same with its electrodes on the scalp. Only the future will show.

== Open Source Circuit Design ==
* [http://opencircuits.com/Programmable_Chip_EEG Open Source Circuit Design ]
* [http://www.thinkcycle.org/ Think Cycle]
* [http://pceegbci.blog.com/ The Programmable Chip EEG Open Source Circuit Design BLog]

== Open source (public) results! ==
PHP will be used to create a database of users and what they sample and choose to share with the open source community.

The database will give statistical analysis on users recordings.

Also the extension of SETI called BIONIC could be used as a distributed library creation of artifacts and data mining.

Please contribute and make the PCEEG a great tool for researching brain computer interfaces.

== A/D Converters ==

The programmable chip EEG needs an A/D converter to convert the analog signal (at the output of the instrumentation amplifier) into digital bits.
We expect this project to require at least 12 bit ADC.

Many Atmel and other microcontrollers have a built-in ADC, but those are at most 10 bit ADC, so that ADC is useless to us -- we are forced to use an external ADC.

What low-cost ADC are available with at least 12 bits?

* $2.50 MCP3301 has 1 ADC input (13 bits)
* $3.50 MCP3302 has 2 ADC input (13 bits)
* $3.50 MCP3204 has 4 ADC input (12 bits)
* $4 MCP3208 has 8 ADC input (12 bits)
* $8 dsPIC30F microcontroller has 8 ADC inputs (12 bits).

== The Goal ==
Eventually, kits could be sold, if there were interest.
More info is available at the PCEEG SourceForge home page at [http://pceeg.sourceforge.net/ PCEEG sourceforge.net].

----
== See also: ==
* [http://wiki.asiaquake.org/openeeg/published/ The OpenEEG wiki]

* [http://pceegbci.blog.com/ The Open EEG Brain Computer Interface BLog]

* [http://www.larryheadinstitute.com/eeg-training.html EEG Training Seminars]

* [http://pceeg.wikia.com/wiki/Main_Page wiki cities on pceeg]

* [http://pceeg.sourceforge.net pceeg.sourceforge.net]

* [http://www.answers.com/topic/miguel-nicolelis miguel nicolelis]

Programmable Chip EEG

2006-11-17T15:15:34Z

72.224.49.207: /* Hardware Overview */

2006-10-19T04:26:45Z

72.224.49.207: /* Status */

== The Programmable Chip EEG ==
Welcome to the PCEEG Wiki, where everyone can add to this EEG brain-computer interface!

Here is a diagram of how the analog signal prossesing boards and the microprossesor board will come together.
[[Image:Pceeg.jpg]]

== What it is and what it can be used for ==
[http://pceeg.sourceforge.net The Programmable Chip EEG] is a Modular Multi-channel electroencephalograph that could be used for a brain-computer interface, biofeedback....

[http://pceeg.sourceforge.net The Programmable Chip EEG] is programmable because it uses [http://opencircuits.com/Programmable_Potentiometers Digitally Programmable Potentiometers]. They are used to set the Gain, frequency range, and can calibrate multiple analog boards for different EEG tests.

== Status ==
We currently have a (preliminary?) [[circuit design]] and a (prelimary) [[PCB layout]]. Eventually, kits could be sold, if there were interest.
More info is available at the PCEEG SourceForge home page at [http://pceeg.sourceforge.net/ PCEEG sourceforge.net].

How You Can Help

*I2C interface diagram for programmable resistors and a/d converters 12 or more bits with low cost.

*SPI interface diagram for programmable resistors and a/d converters 12 or more bits with low cost.

*linear switcher cad schematic drawing from PCEEG technology applied to the Open EEG design with improvements.

*migrate from switcher cad to pcb express.

*migrate from pcb express to eagle cad after testing to further development.

== News ==
The design is switching to EAGLE CAD, because the auto-router is excellent for open-source productivity. It will allow the design to evolve faster and with less work with a wider selection of PCB [[production houses to choose from]].

Here is a picture of the PCEEG being done in [http://www.cadsoft.de/freeware.htm EagleCAD].
[[Image:Eagle_sample.GIF]]
The eagle cad file is here [[Media:PCEEGHD.zip]]

The ideas and monkey to robot arm interface by [http://www.answers.com/topic/miguel-nicolelis Miguel Nicolelis]is very inspiring. He used implanted electrodes to monitor and allow monkeys to control a robot arm as if it was their own. Could the PCEEG do the same with its electrodes on the scalp. Only the future will show.

== Discription of How it Works ==
The daughter signal prossesing board is responcible for filtering and digitising the signals from the body, then the signals are passed to the control board that is the motherboard. The motherboard then can pass the signal to a larger computer.

The differential analog signal is amplified by the instramentation amplifier. Then the signal is amplified and conditioned by high pass and low pass filters.

The common mode signal is inverted summed and sent back to the body to decrese common mode signal thsi is done by the driver right leg circuit.

Band reject filters may be added soon in the future.

Then the analog signals are simultaniously digitized and the digital values can be clocked to the controler motherboard.

The controler board that is the mother board of the system and the signal prossesing daughter boards plug into is the [http://en.wikipedia.org/wiki/AVR_Butterfly AVR Butterfly]

== Parts used in the PCEEG: ==
* [http://opencircuits.com/LT1168 LT1168 Programmable-Gain Precision Instrumentation Amplifier] is used to amplify the weak electric signals coming from the brain through electrodes attached to the scalp, etc.
* Several [http://opencircuits.com/LT1114 LT1114 Low Power Precision OP-Amps] are used for amplification and filtering of the signal
* The [http://opencircuits.com/Digitally_Programmable_Potentiometers Digitally Programmable Potentiometers AD5204] 4-Channel Digitally Controlled Potentiometer is used to make calibration of this device easier. (Historically, a weak point of homebrew designs has been their sensitivity to component value; tolerance and drift have made them require constant tweaking for good results.)

To reduce noise in the readout of the analog part of this circuit, a common-mode feedback is passed back into the body by the driver right leg circuit. Band reject filter may also be used (to reject, for example, 60Hz noise from nearby A/C power wiring).

The analog signal prossesing board will digitise the signal and pass the data to the control board. The control board is based on the [http://en.wikipedia.org/wiki/AVR_Butterfly AVR Butterfly] which will, further process the signals, and provide an interface to a computer & lcd display.

== Open Source Circuit Design ==
* [http://opencircuits.com/Programmable_Chip_EEG Open Source Circuit Design ]
* [http://www.thinkcycle.org/ Think Cycle]
* [http://pceegbci.blog.com/ The Programmable Chip EEG Open Source Circuit Design BLog]

== Open source (public) results! ==
PHP will be used to create a database of users and what they sample and choose to share with the open source community.

The database will give statistical analysis on users recordings.

Also the extension of SETI called BIONIC could be used as a distributed library creation of artifacts and data mining.

Please contribute and make the PCEEG a great tool for researching brain computer interfaces.

----
See also:
* [http://wiki.asiaquake.org/openeeg/published/ The OpenEEG wiki]

* [http://pceegbci.blog.com/ The Open EEG Brain Computer Interface BLog]

* [http://www.larryheadinstitute.com/eeg-training.html EEG Training Seminars]

* [http://pceeg.wikia.com/wiki/Main_Page wiki cities on pceeg]