The Python software library designed to work with OpenBCI hardware.
Please direct any questions, suggestions and bug reports to the github repo at: https://github.com/OpenBCI/OpenBCI_Python
- Python 2.7 or later (https://www.python.org/download/releases/2.7/)
- Numpy 1.7 or later (http://www.numpy.org/)
- Yapsy -- if using pluging via
NOTE: For comprehensive list see requirments.txt: (https://github.com/OpenBCI/OpenBCI_Python/blob/master/requirements.txt)
OpenBCI 8 and 32 bit board with 8 or 16 channels.
This library includes the main open_bci_v3 class definition that instantiates an OpenBCI Board object. This object will initialize communication with the board and get the environment ready for data streaming. This library is designed to work with iOS and Linux distributions. To use a Windows OS, change the init function in open_bci_v3.py to establish a serial connection in Windows.
For additional details on connecting your board visit: http://docs.openbci.com/tutorials/01-GettingStarted
This python code is meant to be used by people familiar with python and programming in general. It's purpose is to allow for programmers to interface with OpenBCI technology directly, both to acquire data and to write programs that can use that data on a live setting, using python.
If this is not what you are looking for, you can visit http://openbci.com/downloads and browse other OpenBCI software that will fit your needs.
The startStreaming function of the Board object takes a callback function and begins streaming data from the board. Each packet it receives is then parsed as an OpenBCISample which is passed to the callback function as an argument.
OpenBCISample members: -id: int from 0-255. Used to tell if packets were skipped.
-channel_data: 8 int array with current voltage value of each channel (1-8)
-aux_data: 3 int array with current auxiliary data. (0s by default)
This code provides a simple user interface (called user.py) to handle various plugins and communicate with the board. To use it, connect the board to your computer using the dongle (see http://docs.openbci.com/tutorials/01-GettingStarted for details).
Then simply run the code given as an argument the port your board is connected to: Ex Linux:
$python user.py -p /dev/ttyUSB0
The program should establish a serial connection and reset the board to default settings. When a '-->' appears, you can type a character (character map http://docs.openbci.com/software/01-OpenBCI_SDK) that will be sent to the board using ser.write. This allows you to change the settings on the board.
A good first test is to try is to type '?':
This should output the current configuration settings on the board.
Another test would be to change the board settings so that all the pins in the board are internally connected to a test (square) wave. To do this, type:
Alternatively, there are 6 test signals pre configured:
--> /test1 (connect all pins to ground)
--> /test2 (connect all pins to vcc)
--> /test3 (Connecting pins to low frequency 1x amp signal)
--> /test4 (Connecting pins to high frequency 1x amp signal)
--> /test5 (Connecting pins to low frequency 2x amp signal)
--> /test6 (Connecting pins to high frequency 2x amp signal)
The / is used in the interface to execute a pre-configured command. Writing anything without a preceding '/' will automatically write those characters, one by one, to the board.
For example, writing
-->x3020000X will do the following:
‘x’ enters Channel Settings mode. Channel 3 is set up to be powered up, with gain of 2, normal input, removed from BIAS generation, removed from SRB2, removed from SRB1. The final ‘X’ latches the settings to the ADS1299 channel settings register.
Pre-configured commands that use the / prefix are:
test (As explained above)
start selected plugins (see below)
Adding the argument "T:number" will set a timeout on the start command.
--> /start T:5
Stop the steam to issue new commands
Writting to SD card a high frequency square wave (test5) for 3 seconds:
$ python user.py -p /dev/ttyUSB0 User serial interface enabled... Connecting to /dev/ttyUSB0 Serial established... View command map at http://docs.openbci.com. Type start to run. Type /exit to exit. --> OpenBCI V3 8bit Board Setting ADS1299 Channel Values ADS1299 Device ID: 0x3E LIS3DH Device ID: 0x33 Free RAM: 447 $$$ --> /test5 Warning: Connecting pins to high frequency 2x amp signal --> a Corresponding SD file OBCI_18.TXT$$$ --> /start T:3
When writing to the board and expecting a response, give the board a second. It sometimes lags and requires the user to hit enter on the user.py script until you get a response.
Select the print plugin:
$python user.py -p /dev/ttyUSB0 --add print
Plugin with optional parameter:
$python user.py -p /dev/ttyUSB0 --add csv_collect record.csv
Select several plugins, e.g. streaming to OSC and displaying effective sample rate:
$python user.py -p /dev/ttyUSB0 --add streamer_osc --add sample_rate
/start to launch the selected plugins.
Create new plugins
Add new functionalities to user.py by creating new scripts inside the
plugins folder. You class must inherit from yapsy.IPlugin, see below a minimal example with
import plugin_interface as plugintypes class PluginPrint(plugintypes.IPluginExtended): def activate(self): print "Print activated" def deactivate(self): print "Goodbye" def show_help(self): print "I do not need any parameter, just printing stuff." # called with each new sample def __call__(self, sample): print "----------------" print("%f" %(sample.id)) print sample.channel_data print sample.aux_data
Describe your plugin with a corresponding
[Core] Name = print Module = print [Documentation] Author = Various Version = 0.1 Description = Print board values on stdout
You're done, your plugin should be automatically detected by
csv_collect: Export data to a csv file.
sample_rate: Print effective sampling rate averaged over XX seconds (default: 10).
streamer_tcp: Acts as a TCP server, using a "raw" protocol to send value.
- The stream can be acquired with OpenViBE acquisition server, selecting telnet, big endian, float 32 bits, forcing 250 sampling rate (125 if daisy mode is used).
- Default IP: localhost, default port: 12345
streamer_osc: Data is sent through OSC (UDP layer).
- Default IP: localhost, default port: 12345, default stream name:
- Requires pyosc. On linux type either
pip install --pre pyoscas root, or
pip install --pre --user.
- Default IP: localhost, default port: 12345, default stream name:
udp_server: Very simple UDP server that sends data as json. Made to work with: https://github.com/OpenBCI/OpenBCI_Node
- Default IP: 127.0.0.1, default port: 8888
streamer_lsl: Data is sent through LSL.
- Default EEG stream name "OpenBCI_EEG", ID "openbci_eeg_id1"; default AUX stream name "OpenBCI_AUX", ID "openbci_aux_id1".
- Requires LSL library. Download last version from offcial site, e.g., ftp://sccn.ucsd.edu/pub/software/LSL/SDK/liblsl-Python-1.10.2.zip and unzip files in a "lib" folder at the same level as
python user.py --list to list available plugins and
python user.py --help [plugin_name] to get more information.
scripts folder you will find code snippets that use directly the
OpenBCIBoard class from
open_bci_v3.py there if you want to run the code -- no proper package yet.
test.py: minimal example, printing values.
stream_data.pya version of a TCP streaming server that somehow oversamples OpenBCI from 250 to 256Hz.
upd_server.pyDEPRECATED (Use Plugin): see https://github.com/OpenBCI/OpenBCI_Node for implementation example.