Daily Archives: March 2, 2018

The OpenBCI Cyton Board

OpenBCI stands for Open Brain Computer Interface. According to OpenBCI, they prefer advancements in science to be made only through open forums with concerted efforts and sharing of knowledge by people having different backgrounds. OpenBCI claims to work towards harnessing the power of the open source movement for accelerating ethical innovations of technologies involving the human-computer interface.

OpenBCI offers high quality, but low-cost bio-sensing hardware for interfacing between the human brain and a computer. Their bio-sensing boards are Arduino compatible, providing high-resolution imaging for EEG, ECG, and EMG signals, while recording them. OpenBCI claims hobbyists, makers, and researchers in over 60 plus countries use their BCI devices to interface brain and computer. Applications of BCI devices include powering machines and mapping brain activity. Anyone interested in brain computer interfacing, neurofeedback, and bio sensing can purchase equipment such as electrodes, sensors, boards, and headsets from OpenBCI. The equipment is affordable and of high quality.

Even if you are only curious about brain computer interfacing, or a new entrant to this field, to start with you need a bio-sensing board from OpenBCI. Select from three types of boards on offer—the Cyton, the Cyton+ Daisy, and the Ganglion. The difference between these boards lies in the number of electrodes they can handle—additional channels allow greater spatial resolution for diversity in research.

The Ganglion board offers four channels, each sampling at the rate of 200 Hz. The Cyton board has eight channels with a sampling rate of 250 Hz each, while the Cyton+ Daisy allows 16 channels at sample rates of 125 Hz. As each channel allows plugging in only one electrode, larger the number of channels so many more electrodes you can use. A Bluetooth dongle compatible with the Ganglion board allows easy connection to a Windows or Linux computer. The Cyton board is directly compatible to Mac computers and a Bluetooth dongle is not necessary.

As the sample rate of the board connected via the Bluetooth dongle depends on the bandwidth of the dongle, for increased sample rates, OpenBCI recommends the use of their WiFi Shield, which transfers data over Wi-Fi and hence is faster than Bluetooth. Users can control the WiFi Shield through requests over HTTP, allowing sending JSON objects with data in nano volts.

Once you have the board, it is necessary to get a set of electrodes or a headset. As the boards come with male header connectors, electrodes with compatible female headers are necessary. For instance, for EMG or ECG, OpenBCI offers EMG/ECG Snap Electrode Cables with matching Solid Gel Foam Electrodes.

The user can plug in these electrodes directly to bio-sensing board and they are ready to use. Another set of electrodes from OpenBCI, the Gold Cup Electrodes, handles EEG signals that include the EMG and ECG. However, it needs the Ten 20 paste to operate. Attachment to the body is very simple, requiring affixing the electrodes with medical tape. Users can connect their own electrodes as well.

For attaching electrodes to the scalp easily and without using any paste, OpenBCI offers their Mark IV headset, which is a frame with dry electrodes. The headset allows easy monitoring of EEG signals from the brain.