Olimex OpenEEG
The Olimex EEG-SMT[1] is a compact, USB-powered EEG device designed for monitoring brain activity. When used with compatible software, it can record data during sleep and help visualize sleep architecture, which is an especially useful feature for those adapting to a polyphasic sleep schedule.
Signal quality depends on several factors, including electrode placement, electrical interference, and the user's environment. While results may vary, many users have successfully used this device to monitor sleep stages.
Generally, sleep stages follow a distinct pattern, as illustrated in the figure on the right. For more details, see section Sleep Stage Identification.
Components
Hardware
The main component that has to be acquired is the EEG-SMT device[1], which can be ordered directly from the Olimex website. Next, you will need electrodes. There are two options:
The second option is slightly more expensive but is the recommended choice. Active electrodes provide better performance under imperfect conditions and require no skin preparation.[5]
Finally, you will need to purchase a USB A to B cable. [6] It is recommended to get a long cable, such as 1.8 meters, since you will be sleeping with the EEG connected to a laptop (in the default setup). The cable should be long enough to allow comfortable movement.
Lastly, you will need a way to secure the electrodes to your head while sleeping, which can be done using an elastic headband or other methods. The hardware setup section provides more details.
The standard way to set up an Olimex EEG for sleep recording is to connect it to a laptop during sleep. This method is the most widely tested by the community, so if you're unsure where to start, it's the recommended option. However, bringing a laptop to bed each night may be inconvenient. In that case, it's also possible to use a Raspberry Pi[7] or a PinePhone, though these setups require DIY work and are not covered in this guide. If you manage to get one of these alternative setups working, please consider joining the Discord server and sharing your configuration. Your contribution would be much appreciated.
Software
The software setup can be done on both Windows and Linux, and potentially on macOS (though this has not been tested).
The first component you'll need is a program to record sleep sessions. The recommended options are OpenViBE[8] or SleePi[7] for Raspberry Pi. Once your recordings are complete and saved, you’ll need to load them into another program to mark the sleep stages. SleepEEGTools is the recommended choice for this task.
Additionally, you can use DatPlot to view the raw EEG data, for example, to visualize REM movements or detect K-complexes.
Hardware setup
First, identify one PE (passive electrode) and four AE (active electrodes). As shown in the image, active electrodes contain a black component (a chip), while passive electrodes do not.
Plug the electrodes into the main device: connect the PE to the DRL socket, and plug the remaining electrodes into the other four input sockets. Note: It’s recommended to avoid unplugging the electrodes from the device, as this can risk damaging the electrode jacks. Try to keep them plugged in at all times.
Electrode positioning
There are several ways to position the electrodes on the head. The main configurations are discussed below.
DRL in the middle, CH1 and CH2 on the sides
The simplest configuration places the DRL electrode in the middle (FPZ), with CH1+ and CH2+ above the right eyebrow (FP1), and CH1– and CH2– above the left eyebrow (FP2). This setup is reliable and allows both channels to record the same data, providing redundancy and improving data reliability.
DRL on the ear
As a variation of the setup above, the DRL electrode can also be placed on the ear instead of the center of the forehead.
CH2 around the eyes
It's also possible to sacrifice redundancy in favor of collecting more data. The first channel is used as before, but CH2 can be repurposed, for example, by placing it near or around the eyes to capture more detailed REM data.
Electrode placement solutions
The electrodes need to remain attached to the head during sleep to record data. There are several ways to keep them in place, some of which are described below.
Elastic headband
The easiest way to attach the electrodes is by wearing an elastic headband across the forehead, with the electrodes placed inside. It should be snug enough to keep them from slipping out. For added convenience, the electrodes can also be sewn into the headband to avoid repositioning them manually each time.
Ski goggles or sleep mask
This method involves more DIY effort, but it allows electrode placement around the eyes to collect more detailed REM data. However, keeping the sleep mask or ski goggles securely in place during sleep can be challenging, especially for side sleepers, as the electrodes may shift. This should be taken into account.
Software setup
The process of setting up the software will vary significantly depending on your operating system (assuming installation on a laptop). However, the general steps are similar and will be outlined in this guide.
Windows
Linux
MacOS
This setup has not been tested on macOS yet, so contributions are welcome.
Sleep stage identification
References
- ↑ 1.0 1.1 "Low Cost Open Source EEG Device Completely Assembled USB Interface". Olimex. Retrieved 2025-06-21.
- ↑ "A first look at the Olimex EEG-SMT". Daniel's Visionarium. Retrieved 2025-06-21.
- ↑ "Low cost open source EEG device passive electrodes with 1m shielded cable to be used for the DRL connection". Olimex. Retrieved 2025-06-21.
- ↑ "Low cost open source EEG device active electrodes with 1m shielded cable". Olimex. Retrieved 2025-06-21.
- ↑ "OpenEEG". Olimex. Retrieved 2025-06-21.
- ↑ "USB A to B cable 1.8m". Olimex. Retrieved 2025-06-21.
- ↑ 7.0 7.1 "SleePi". Github. Retrieved 2025-06-21.
- ↑ "Software for Brain Computer Interfaces and Real Time Neurosciences". OpenViBE. Retrieved 2025-06-21.
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