node9909 / openbci-ros

OpenBCI library ported to run completely in ROS

OpenBCI_Python_ROS

This is a Python software library built upon OpenBCI_Python to run create an interface between the OpenBCI Ganglion and ROS. I have tested it on the Ganglion using BLE and the guide below is written for Ganglion. I have not tested it on Cyton and it may need additional tweaking to work with the Cyton board.

Getting Started

Prerequisites

• Address the dependencies listed on OpenBCI_Python
• ROS Lunar Loggerhead (may or may not work on older versions of ROS)
• Make sure that when you clone, you use the recursive flag as instructed on OpenBCI_Python

Setting Up

Go to your ROS workspace and create an empty package and build the package. Follow Creating a ROS Package tutorial and Building a ROS Package tutorial if you're not sure how. Open up Terminal and move into the root directory of your ROS workspace. Gain root access using sudo bash and run

source devel/setup.bash

Note: Remember to do this everytime you open a new terminal and gain root access using sudo bash.

Move into the src/<your_package_name>/scripts. Clone the all the files in this repository into your current directory. Remember to use the recursive flags as listed on OpenBCI_Python. Move into bluepy/bluepy and type make. Open a new terminal and run hcitool dev. Find out the hci number of your CSR bluetooth module. Open btle.py from bluepy/bluepy and find the Scanner class definition.

class Scanner(BluepyHelper):
    def __init__(self,iface=1):
        BluepyHelper.__init__(self)
        self.scanned = {}
        self.iface=iface

Update the iface variable to the hci number of your CSR bluetooth module. For example, it should be 1 if your module is listed as hci1.

Go back to <your_workspace>/src/<your_package_name>/scripts . Make talker.py and listener.py excecutables by typing:

chmod +x talker.py
chmod +x listener.py

Running it

Launch ROS core. Open new terminals and move into <your_workspace>/src/<your_package_name>/scripts.

Launching the Publisher

Run rosrun <your_package_name> talker.py --board ganglion --add talker with root access.

This basically runs the whole OpenBCI_Python as a ROS node. The --add talker adds a ROS publisher as a plugin for the OpenBCI_Python library. talker.py is a modified version of user.py from OpenBCI_Python

Now type /start to start publishing data to a ROS topic. You can stop publishing by entering stop.

Launching the Subscriber

Run rosrun <your_package_name> listener.py

Functionality

The talker function inside talker.py has all the code for publishing data. Feel free to tweak it and publish whatever data you want from the board. The function acts like the rest of the plugins from OpenBCI_Python. But instead of launching the plugins as Threads, the talker function is run from the main program and a seprate thread is started with the function murder. The murder thread waits for input from the user to stop streaming data. I made this ugly hack because ROS doesn't give permission to publish data to ROS Topics from threads(for the method the plugins use. I'll look into other threading solutions for ROS).