Bliss Meter

This software is displaying EEG coherence between two spatially separated points on the scalp (usually F3 and F4). The software is designed to be used in conjunction with an affordable 2-channel EEG machine, called EEG-SMT from a Bulgarian company OLIMEX, which specializes in PCB production.

Looking for a 4-channel EEG machine? Visit the new Bliss Master page.

The hardware

You can buy the EEG machine directly from the manufacturer. The EEG machine costs 99 Euro, but you will also need five passive electrodes for 5 Euro each. Then you will probably also want the USB cable (such cables are used for connecting the printers). All this things you can buy directly from the manufacturer (EEG-PE and USB-A-B_CABLE at the bottom of their page), but add to the final price the tax and the shipment cost. The final price will likely be around 150 Euro.

You will also need some EEG gel, which you can find on-line for a few Euro. Alternately you can use salty dough as well. Also you should get some medical tape to attach the electrodes to the skin.

NOTE: You will not need the electrodes from OLIMEX, nor the gel, nor the tape in case you make your own electrodes.

This machine is a part of the OpenEEG project, so you can find some free software, which can be used with this machine, like OpenVibe or BrainBay. But there is also a special software, which was specifically designed to be used for demonstrating brainwave coherence. It is called Bliss Meter. All these programs only work for Windows.

Getting started with the EEG machine

After you have purchased the EEG-SMT machine, you will also need to install the drivers. The EEG-SMT machine communicates with a PC through a FTDI chip. To make this chip communicate with Windows, you will have to install the driver. You can download the driver setup program by clicking here. Extract and run the driver setup program to install the driver.

Do not connect the EEG-SMT machine to the PC just yet, because there might be some problems to overcome. In many cases the EEG-SMT machine is considered by Windows to be some kind of a mouse, and that will interfere with the pointer on the screen. It is a bit annoying, but fortunately there is a fix.

Open Device Manager, then click on Mice and other pointing devices. Now connect your EEG-SMT machine via the USB port, and watch what is happening to your mouse pointer on the screen. If it behaves funny, you will have to disable the new mouse, that just appeared in the Device Manager. This part is a bit tricky. You will have to persevere and keep trying to point to the new mouse entry in the Device Manager, right-click on it, then click Disable.

Connecting the electrodes

You can use the passive electrodes provided by OLIMEX. These electrodes are made out of a coaxial cable with a small printed circuit board (PCB) attached to it. On the bottom of this PCB you will see a fine gold-plated mesh pattern. This mesh pattern has to be in contact with the skin. To make a better contact, apply the EEG paste on the mesh, then place the electrode on the desired spot. Use a tape to fix the electrode on the skin.

For best results connect the electrodes in the following way. Connect CH1+ to F3, CH2+ to F4, CH1- to the left mastoid, CH2- to the right mastoid. Connect DRL to the hand. The F3 and F4 codes come from the 10-20 system of EEG electrode placement. These two points are on the forehead, approximately above the eyes, next to the original hair line. The CH1+ and CH1- connect to the left side of the head, while CH2+ and CH2- connect to the right side of the head. The mastoid bone is behind the ears.

The early studies on EEG coherence during meditation have been using linked reference (CH1- and CH2- are wired together). It is advisable to follow this procedure to get comparable results. The electrodes from OLIMEX are not wired together, so you would need to make them yourself.

Before connecting the electrodes to the skin it is advisable to rub those spots on the skin with some alcohol on a paper tissue. Press firmly, but not too strong not to injure the skin. This will provide a much better contact with the skin by removing the top dead layer of the skin and removing the oil.

Running the software

After having connected all the electrodes as described above, connect the EEG-SMT machine to the PC laptop via the USB cable. It is advisable to only use a laptop running on battery for best results (least interference from the mains). The software is available in the Download section. Run the software (after you have installed the driver - see Getting started with the EEG machine section above). If you have connected the EEG-SMT machine, you will be able to record data. Otherwise you can load an old recording, by pressing the Load button. There is a Start button in the top left corner of the Form. Press this button to start the measurement. Now this button reads Stop. Press it again to stop the measurement. In the top in the middle you can see the Acquisition time display. If you have been running the measurement for more than one minute, the data will automatically be saved in the same folder, as is the executable. You can provide a name of the subject (or his/her initials), which will become part of the name of the saved file. If no name is provided, the generic name, for example EEG1612031155.wav will be saved. The numbers in the name of the file are reflecting the date and time of the recording.

In order to make sure you are getting good data, follow this procedure. Start with the Alignment Tab, no noise filtering and full range (settings on the right side of the screen). You should clearly see two lines. If the electrodes are on the forehead, you should also be able to clearly see the effect of blinking with the eyes. See the Features section for more details.