In this post we are trying to share our experiences using Emotiv Epoc headset.
Different software to use the tool
We are using three different applications to get information from the head set:
By the time this document has been written you can get this software through (http://affordabletechnology.com.au/Neuro/neurovault.htm). For more detail about how to install and use the NeuroVault application please review the post on “Tools: Emotive and NeuroVault”.
Regardless on the software you use, you can get the following states:
- Cognitive states: NEUTRAL, PUSH, PULL, LIFT, DROP, LEFT, RIGHT, ROTATE_LEFT, ROTATE_RIGHT , ROTATE_CLOCKWISE, ROTATE_COUNTER_CLOCKWISE, ROTATE_FORWARDS ROTATE_REVERSE, DISAPPEAR.
- Expressive states: BLINK, WINK_LEFT, WINK_RIGHT, HORIEYE, EYEBROW, FURROW, SMILE, CLENCH, LAUGH, SMIRK_LEFT, SMIRK_RIGHT.
- Affectiv states: EXCITEMENT, MEDITATION, FRUSTRATION, ENGAGEMENT, BOREDOM.
Below you will find some tips that we hope make your life easier while installing, using, and training the headset.
Setting up the hardware
Once the software is installed it is needed to install the hardware: the dongle.
- Windows will detect it, just give the OS the time needed to detect and install the drivers for the dongle.
- It is recommended to use these applications under Windows XP.
- Wireless LAN and wireless phones works in the same frequency of the dongle (2.4 GHz), so it is very difficult to get the headset work properly on environments with this kind of equipment near of the computer with the dongle.
- Bluetooth dongles might also generate interference. If for any reason you are using a Bluetooth dongle in the same computer, you can try to plug it in a USB port in the opposite side where you plug in the emotive dongle. If your computer does not have a USB port in an opposite side, you can use an extension.
- f you are using multiple headsets in your experiment, use each one connected to a different dongle, in order to avoid confusion plug them one by one, this mean connect and match the headset with the dongle, once it is connected and matched, do the same process for the remaining headsets.
Setting up the head set in the subject’s head
In order to have a better performance with the headset consider the following:
- The size and shape of the head could matter. With subjects who have a small head (some kids and young females) it would be difficult to get a good performance.
- It is better to set the headset starting either from the front or the back of the head instead of pulling out the arms of the headset and try to set it from the top of the head.
- Do not worry if the subject gets to the experiment with wet hair, this do not affect at all.
- If the subject has long hair, it is better NOT to wear it in a ponytail. Some times you will need to move the nodes around the head and through the hair in order to get the best contact.
- Dense hair could be problematic.
- It is better to put the reference nodes (the ones with the rubber cups instead of pads) into the ears or just behind them.
- Sometimes If one node is not doing contact properly, the rest of the nodes never gets alive, particularly the nodes at the back of the head.
- If you are working with affective states you will want that all your node gets the best contact possible (this is showed with a green color on the node), you might work with some of the nodes on orange or yellow and you still get good information, however it depends on the emotion you are trying to measure the nodes you might want to assure that gets the best quality. See the emotions and nodes section below to learn more about this.
- When you finish a session it is better to disconnect the headset and then turn off it, and then do the change of subject and turn on the headset and try to connect it to the app.
- Some times if you are getting problems to map the headset with the dongle, ask the subject to get closer to the computer with the dongle, this helps. Once the mapping process is done, the user can move away from the computer.
Recommendation in order to start your session
To a more complete guide, please review the document named: Installation of NeuroVault.
- Please review that the webcam is well connected and that windows XP is loading up it correctly.
- Plug the dongle first wait until ONE of the leds is blinking on green. Load up the neurovault app. Turn on the headset and wait until the second green led starts blinking.
- Use the “Connect” button to start the communication between the headset and the app.
- Wait until the three rows (signal quality, battery level, and signal reception) are green.
- Check in the second window that all the nodes are in green (yellow at least).
- Check in the “Video/Audio” tab that the web cam is selected.
- Use the “Select a file” button to define the name of the new file.
- Now you can use the “Preview” button to see if the video/audio input is working properly.
- Now that you are previewing you can use the “Record” button to record the data. You don’t need to change anything in the checkboxes for the save data options.
Emotions and nodes
The ideal scenario is that all the nodes gets the best quality while you put the headset on the subject’s head, this is showed in the application when all the nodes are green (see the image below), some times it possible to work and get good enough data when some nodes are orange or yellow. However, it depends on the emotion you are measuring if you work with a lower quality on a node or not.
According with our experience each node contributes in more or less level to recognize each emotion. Please see table below to learn more about which nodes contributes to each emotion, these nodes appears surrounded on red.
|AF3, AF4, F3, F4, F7, F8, FC5, FC6||Meditation|
|None in particular||Excitment|
|O1, O2, F3, F4, F7, F8, FC5, FC6||Engagement|
While training the Emotive suite to use the cognitive and expressive states there are some issues to consider:
- Training for cognitive actions (control movement) takes more time than they claim.
- Having more than two different movements (e.g. push, pull, right, left, etc) gets really difficult to train, due the fact the algorithm gets easily confused.
- Of course, the train is needed to every single subject.
- There is a username that identifies each user and the train he or she has done. It is possible to copy this file to a different computer.