Mentalab EXPLORE User Manual
Mentalab Explore is a powerful and flexible solution for mobile biosignal recordings designed for research, development, and educational purposes. It offers research-grade precision and easy-to-use open-source APIs to collect, analyze, and visualize data from multiple biosignals including EEG, EMG, and ECG. The device can operate in both online and offline modes, allowing you to stream data in real-time or record and analyze it later. Explore comes with an optional 512 MB flash memory to store your recordings and a comprehensive set of position and device sensors to capture additional contextual information.
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Table of Contents Acronyms and Abbreviations 2 Definitions 2 1 3 2 3 Introduction 1.1 Intended Use 3 1.2 Release Notes 3 1.3 Product Certification 3 1.4 Safety 4 Technical Information 6 2.1 Explore Outline 6 2.2 Contents 6 2.3 Device Specifications 7 Operation Instructions 8 3.1 Operating Modes 8 3.2 First Setup 8 3.3 Device State Diagram 12 3.4 LED Codes 13 3.5 Button Commands 14 3.6 Data Structure 15 4 APIs 16 5 Device Troubleshooting 17 1 Acronyms and Abbreviations API Application user interface ECG Electrocardiogram EEG Electroencephalogram EMG Electromyography ExG EEG / EMG / ECG SPS Samples per second Definitions Recording session The period in which the device is recording. For each recording session, starting automatically at device start up, a bin file in the flash memory will be generated. Advertising As part of the Bluetooth connection process, the Explore device will advertise that it is available for a connection to a host machine. When it is connected, the Explore device becomes the slave device. Reference Bluetooth Core Specification Version 4.0 for more information. Host machine The computer or smartphone that initiates the connection and is the master in the connection with the Explore device. Pairing Establishing a connection between two Bluetooth devices. Online mode Data will be transmitted to the host machine in addition to being stored on the device memory in duplicate. The host machine can send data and commands to the device. Offline mode Data will be stored only in the device memory. No host machine is connected to the device. 1 Introduction 1.1 Intended Use Mentalab Explore is a biosignal acquisition device developed mainly for research, development, and educational purposes. It is not intended for medical use. Mentalab Explore is used by scientists, developers, innovators, and students around the world in their own custom applications. 2 This document serves as technical instruction manual for Mentalab Explore devices. Any modification, publication or distribution of parts or the whole document are not permitted without prior written consent by Mentalab. Copyright Mentalab 2020. All rights reserved. 1.2 Release Notes Date Firmware Explorepy Documentation Changes 31.08.2020 2.1.4 1.1.0 MLExploreV1.1 First release 1.3 Product Certification Mentalab hereby declares that the Explore product series is in accordance with the requirements and relevant provisions of EU directives: 2014/30/EU 2014/53/EU 2015/863/EU 3 1.4 Safety Preventing Misuse Any operator of a Mentalab Explore device should read the instruction manual specific to the device and API versions. The device is only to be operated according to the instructions. Mentalab Explore is not intended for medical use, including any diagnostic or therapeutic applications. Mentalab Explore tolerates continuous exposure of [-2.7V, +2.7V] without electrical damage and has a built-in ESD protection that protects against burst exposure: • IEC 61000-4-2 Level 4 ESD Protection – ±12-kV Contact Discharge – ±15-kV Air Gap Discharge • IEC 61000-4-4 EFT Protection – 80 A (5/50 ns) • IEC 61000-4-5 Surge Protection – 2.5 A (8/20 µs) When using the Explore system with other hardware or implanted electrical cardiac or neural stimulators (pacemaker, tDCS, tACS, DBS, etc), the above values should not be exceeded to provide safe use. Using Explore with additional hardware can affect the accuracy of the recorded signals. Mentalab Explore is not protected against electrical defibrillation. The device and electrodes must be detached from the subject’s skin beforehand. Before use, inspect the device and accessories thoroughly for possible damage to connectors, sockets, and cables. Especially, ensure that the electrode cables are intact. Any part of the equipment must be replaced immediately if damaged or not working correctly. The device and its accessories must not be exposed to increased mechanical stress. Do not open or modify the device, it will void the warranty. Using controls, adjustments, procedures, connections, or signal types other than those specified in the Explore documentation may result in electrical and mechanical hazards. Only use Mentalab approved accessories with this device. If an accessory is not listed, please contact us for technical support. Battery While being charged or connected to a PC / tablet, the device should not be connected to any subject. The external power supply must fulfill the IEC/EN 60950-1 and SELV requirements to be used safely with the device. Do not charge your device with anything other than the USB port of a 4 certified laptop / PC or a certified mini USB charger. Using a non-certified power supply can lead to electrical and fire hazards. Users should not attempt to replace or disconnect the Explore’s battery. Environment Precautions The Explore device is not designed for use in inflammable or explosive environments. It should be used at room temperature. Exposure to conducting material, liquid, fire or heat above 45° C can lead to overheating or electrical discharge. Mentalab Explore is not to be used in wet environments either, as liquid intrusion can cause electrical hazards. When applying electrodes on the subject’s head, the cap and the subject’s hair should be dry. Protect the device and electrodes from electrostatic discharge and take all precautions regarding electromagnetic compatibility. Signal Transmission The operation of the movement sensors and wireless transmission can be compromised within shielded rooms. It is not possible to communicate with the device from outside of the shield. Mentalab Explore uses the 2.4 GHz band for wireless transmission, so nearby Bluetooth and wireless devices can cause interference. Therefore, ensure that enough transmission bandwidth is available in your environment. We recommend working in environments with low wireless and noise interference for better performance. If the equipment is not installed according to the instructions, it may interfere with nearby devices. If it does, which can be determined by turning the equipment off and on, try the following measures: − Reorient or relocate the receiving device. − Increase the space between the Explore equipment and other wireless devices. − Use the equipment with proper shielding, especially if a device with high wattage is nearby. − Consult the Explore technical support. Equipment Maintenance Mentalab Explore uses lightweight, highly flexible cables to provide comfort and easy cap mounting, especially for multi-channel recording. These cables are sensitive and need to be treated with special care. Following these guidelines will prolong the lifetime of ExG electrodes: 5 − Do not pull on the electrodes’ cables and avoid knots. Do not cut, kink or pinch electrode cables; light bending is safe. − Avoid exposure to direct sunlight and chemicals. − Clean the cables and electrodes from remaining gel, disinfectant, paste or other residues. Do not use detergents with chlorine or other corrosive agents to clean the equipment. − Protect the Explore unit from liquid contamination. Ensure that the whole equipment is completely dry before storing. 6 2 Technical Information 2.1 Explore Outline The Mentalab Explore device is a powerful and flexible solution for mobile biosignal recordings. It combines research-grade precision with great usability in a mobile format. We offer several easy-to-use, open-source APIs. Mentalab Explore and its APIs provide you with rich and easily integrable data pipelines, so you can focus on your application. You can choose to work with data offline or in real-time. Data can be streamed to any host device with a Bluetooth module, such as computers and smartphones. Besides precise multi-channel-ExG, Mentalab Explore also contains a comprehensive set of position and device sensors. Figure 1. Explore system overview 2.2 Contents Based on your order, the box you received should include: − − − − 1 Mentalab Explore device 1 USB 2.0A to micro-USB cable A quick-start guide Electrodes and caps of your choice − Optionally: electrode gel and cleaning solution 7 2.3 Device Specifications No. of Channels 4 or 8 ExG Sampling Rate 250 (default), 500 or 1000 sps (in beta phase) Operation Time 8h online recording, 12h offline recording Differential Input Range 400 mV Input Impedance > 1 GΩ Resolution 24 bits USB Output Interface USB 2.0 Additional Sensors Magneto- / Gyro- / Accelerometer: 20 sps Device Temperature, Battery: 1 sps Flash Memory Size 512 MB Dimensions 41mm * 42mm * 18mm Bluetooth Range 10 m The following picture shows the Explore device label. You can also find it on the Explore case and on the box. The last four digits on the label define the device’s Bluetooth name. For example, the label below corresponds to a device whose Bluetooth ID is “Explore_1438”: Figure 2. Example device label 8 3 Operation Instructions 3.1 Operating Modes Mentalab Explore has two main operating modes: offline and online. When in offline mode, the device collects data and stores it in its internal flash memory. Users can extract the recordings from the flash memory via a micro-USB cable after the recording. Data can be retrieved and transformed with different tools provided in the APIs. During online mode, data is transmitted via Bluetooth in real-time, enabling the user to collect, monitor, and visualize data, and to configure the device through one of the available APIs (explorepy, exploreMATLAB and libexplorecpp). In this mode, the Explore device sends the data and communicates in configuration packets with the API on the host machine. While you can start using the device right out of the box, we recommend charging it for at least 1 hour. To charge the device, connect the micro-USB cable to a compliant source. The green LED indicates sufficient battery. After charging, unplug the device from the power source. 3.2 First Setup Set up the measurement electrodes on your subject in your preferred configuration. Each channel (1-4 or 1-8) is recorded against the reference electrode. The electrodes are configured in the order depicted below. In a 4-channel device, channels 5-8 are inactive. Figure 3. Device configuration Push the button to turn on your Explore system. At system start, the LED shows the battery level (green > 60 %, yellow 30 - 60 %, red < 30 % charge remaining). Upon normal start, the device begins to record on the flash memory immediately. It starts advertising and waits for a Bluetooth connection to a host machine. During advertising mode, the LED blinks in blue at 2 Hz (twice per second). If no connection is established after 4 minutes, the device will automatically go to offline mode. In this state, the LED blinks in green at a rate of 1 Hz and the Explore keeps recording data in the internal memory. You can leave the device in recording mode for as long as you wish. With a full battery, recording for 9 up to 12 hours is possible. If you want to start in offline mode directly, turn on the device with three button pushes. If you press the device’s button once during recording, a marker packet with the event timestamp is set and written in the data. This can be used for labelling certain events, for example the beginning and end of recording periods. To turn off the device, keep the button pressed until the LED turns red. The device will shut down with three red blinks. Wireless Transmission If you want to stream and record data on your PC or smartphone, you must first pair your Explore device. Here is an example of how to do this on Windows: First, go to your Bluetooth settings and choose “Add Bluetooth device”. Then, add the Bluetooth device whose name corresponds to your Explore (i.e. Explore_ followed by the last 4 digits on the device label). 10 Your Explore should now be paired to the host machine. The connection can be established using the APIs (see section 3). Once the connection is active, wireless data transmission starts directly. Meanwhile, data is stored in the device memory simultaneously. Bluetooth Dongle A Bluetooth dongle may be helpful or even necessary if your host machine has not been equipped with Bluetooth, or if it is not working properly. Depending on your Bluetooth module and operating system, difficulties using all Bluetooth functionalities can occur. In this case, please notify our support. We can provide a Bluetooth dongle to help you maintain the desired mobility and flexibility. Here is an example of how to use a dongle on Windows: First, if you have paired an Explore device, remove it from the Bluetooth paired devices list before inserting the Bluetooth dongle. Open the device manager and disable your Bluetooth adapter driver (do not “uninstall device”). Attach the Bluetooth dongle, update the device manager list, and the dongle should activate automatically. 11 Pair your Mentalab Explore device in the Bluetooth menu again, as described in the previous section. Flash Memory Mentalab Explore devices have an optional 512 MB of flash memory. The device starts recording data in the flash memory as soon as it is turned on (if no “memory full” error occurs). All data is saved into a binary file (.BIN) onto the flash memory. This file can be converted to BDF+ or CSV format with the help of the APIs. A pink LED blinking at 2 Hz on startup means that there is not enough free space on the device memory for a long recording (440MB, enough for 8h recording at 500 sps). By pressing the button twice within three seconds after startup, the system starts deleting files, starting with the oldest one until it can allocate enough space. Then it starts recording normally. Do not forget to retrieve the binary files from your device before deleting data. To do so, connect the device to a PC via a USB port. The device memory will show up as a drive in your OS, you can transfer the files to your computer as usual. USB Connection Always turn off the Mentalab Explore device before attaching it to a PC or charging. The device starts recording a file into the memory automatically after start-up. Attaching the device to a USB port without prior shut-down can terminate the recording session abruptly. If this happens, recorded data files can be incomplete, potentially causing a memory full error on the next run. If you need to save the recorded data, copy it via USB before freeing up space on the flash memory as explained above. Connecting the device via micro-USB will reset the device. In case of a device freeze, please connect your device to a USB plug. 12 3.3 Device State Diagram The following diagram gives an overview of the Explore device’s behavior. 13 Figure 4. Explore device system states 14 3.4 LED Codes LED Color Blinking Pattern Description Red / Yellow / Green At device startup, about 3 sec Startup in progress. Green > 60 %, yellow 30 – 60 %, red < 30 % battery left. Blue Blinking 2x / sec Bluetooth visible and advertising. Blue Blinking 1x / sec Bluetooth visible and connected to the host machine. Online mode in progress. Green Blinking 1x / sec Bluetooth is invisible; offline mode in progress. Pink Blinking 1x / sec, at device startup “Not enough memory” error. Pink One-time flash Button has been pressed; a marker with the timestamp corresponding to the button event is stored and transmitted. Red 3x flash Button has been pressed and held. The device will turn off. 3.5 Button Commands Action State Effect Pressing the button once Device off Device will turn on. Double click Memory full error, LED blinking in pink. Frees up space on flash memory and returns to advertising mode. Double click Device in startup Skips advertising and goes to the offline mode. Double click Device in offline mode Starts advertising mode, device now visible via Bluetooth. Keeps recording on flash memory in parallel. Single click Device recording, online or offline A marker is generated with a timestamp corresponding to the button event. Press & hold All states Device will blink in red three times, terminate the recording session, and turn off. 15 16 3.6 Data Structure Explore devices contain 4 or 8 channels of high-precision ExG sensors, 3 independent movement sensors (Accelerometer, Gyroscope, Magnetometer) and 2 environment sensors (Device Temperature, Battery level). The sensor data is always saved in the device’s flash memory, while also being transmitted wirelessly when in online mode. Additionally, the device sends the following information to the host machine: − A device information package including firmware version, ADC mask (active channels) and sampling rate. − Markers (upon button push) which include the timestamp of button push and a code from 0 to 7. This code is generated by a counter in the MCU and each button press will increase this number by one. When it reaches 7, the counter will be reset to 0. This code can be used to distinguish it from digital markers (digital markers have a code larger than 7) and to detect missed marker packets, since two consecutive markers should have consecutive codes. − Timestamps: The host machine can send a packet to Explore to synchronize the device with it or to indicate the timepoint at which the recording has started on the Explore device. The value in the host timestamp field of the mentioned packet contains the host timestamp based on the UTP protocol. Once you connect to the device via Bluetooth, this packet will be transmitted to the device automatically. Based on the time the packet has been sent and the internal clock timer of the device, the name of the current recording will be updated to contain a time tag associated with the start of recording (e.g. DATAxxx_01Jan2020_16h53m.BIN). If the recording is done completely in offline mode without any Bluetooth connection, its time tag field in the device name will contain dummy values (e.g. DATAxxx_ddmmmyyyy_xxhxx.BIN). 17 4 APIs To use the device in online mode, configure its settings or convert offline data, we recommend using our main API, Explorepy for Python, which can be integrated into your desired application. Real-time impedance measurement, remote data recording and browser-based data visualization are some of the key features you can access with it. Figure 5. Browser-based dashboard for visualization of ECG data. Please refer to the online documentation for the installation of Explorepy and its dependencies, as well as a comprehensive description of the functionalities: https://explorepy.readthedocs.io If you prefer to work with C++ or MATLAB, you will find the documentation for these APIs LibExploreCpp (C++) and ExploreMATLAB - on our GitHub page. Note, however, that these APIs were built for earlier firmware versions and are not yet up to date, so make sure your device has the firmware version corresponding to the API you are using. All Mentalab's application-sided code is open, so we invite you to use it and contribute to its development. The three APIs can be found on GitHub: https://github.com/Mentalab-hub/ 18 5 Device Troubleshooting No. Error Cause Solution TD-1 When I turn on the At the startup, Explore checks To free-up space on flash memory, Explore device, it blinks if there is enough space on you can press the Explore’s button in a pink light and then flash to record data for 8 twice while the pink light is turns off automatically. hours. If not, it will blink in blinking. This should be done within pink to show memory full 3 seconds, otherwise the device will condition. shut down automatically. The 3 seconds time constraint is for the purpose of avoiding unintended data loss. TD-2 The size of the created Explore secures enough space The data is safe, you can retrieve it file on the flash for 8 hours of recording by as usual. memory is inconsistent allocating it at the beginning Turn off the device and connect it with the duration of of a recording session. At the to a PC, then copy the data from recording. end of the recording session, memory. Then turn the device off the unused space will be again, and if it blinks in pink, free up deallocated. The user may space as explained in #TD-1. interrupt this action by Although not necessary, the user plugging the device in via USB can format the memory as while it is still operating, explained in the API which blocks the device from documentations. deallocating properly and the user finds a file with a larger size than expected. TD-3 Explore shows full As in #TD-2, this is likely Always turn the device off before memory while it should caused by a corrupted data attaching it to the USB or charging still have enough file which is larger than it. available space on flash intended, because the device memory. was plugged into a power source and forced to undergo a reset, terminating the recording and device operation. TD-4 Explore has frozen, it Unexpected error or hardware Plug and unplug the device to USB. does not respond to damage. This will reset the hardware and the button presses. device will turn off afterwards. Turn on the device and it is ready to be used. If it does not solve the problem, please contact Mentalab’s technical support. 19 TD-5 I cannot see the LED Either the device is out of Charge and reset the device by lights. battery, or the LED is damaged plugging it to a USB connection. / an unexpected error has If not resolved, contact us. occurred. TD-6 Device is not If not connected for a while or Press the button twice like a double discoverable, and it is if has received a disconnect click. It will make the device visible emitting green light. request from host machine, again. The device should start the device will go to offline blinking in blue at 1 Hz once mode. successfully becoming visible again. You can now pair and connect to the device. TD-7 Device cannot connected and emitting blue light. be Bluetooth error. is Turn the device off and on. Reset the program and see if the problem has been solved. If still not able to connect, unpair the device and pair it again. TD-8 Signal is too noisy. Bad electrode connection or Check if the electrodes are properly Bluetooth interference. connected, especially the reference electrode. Make sure the cables are intact and correctly connected to the Explore, and that the impedance values are low enough. Else, try moving the Explore closer to the host machine, or turning off other Bluetooth devices nearby which may interfere. TD-9 I observe a sinusoidal Impedance mode is active. signal instead of applied signal. Disable the impedance mode (e.g. with Ctrl+C) or simply restart the device to reset it to the default configuration. TD-1 My device turns off Record offline mode is Explore advertises for 4 minutes 0 after being meaningless for devices after startup or if disconnected disconnected for a without flash memory. So, from a device and attempting to while despite battery after being advertising for a reconnect. Make sure to connect being fully or partially while and not being able to your device to a host machine charged. connect, the device will turn within that time span. off. 20 TD-1 The recorded file’s The host machine’s date and The device receives this time tag 1 name does not have time settings are incorrect. from the host machine. It is likely the correct time tag. that your system’s date and time are not correct, especially if you use a dual boot system on your host machine. TD-1 I have connected the The Bluetooth connection was If the file created on the flash 2 device to the host interrupted while transmitting memory is partly corrupted, the machine, but the time this information, or the device device shut down incorrectly. tag of the recorded file has not turned off properly. Always turn off the device before on the device still plugging it to the USB. If the file is contains dummy values healthy, the Bluetooth connection (DATAxxx_ddmmmyyyy has been interrupted: remove the _xxhxx.BIN). source of electro-magnetic interference, e.g. electrical equipment or other wireless devices nearby. 21 [email protected] [email protected] https://mentalab.com https://github.com/Mentalab-hub https://explorepy.readthedocs.io Mentalab GmbH Weinstr. 4, D-80333 Munich, Germany 22
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Key Features
- Mobile biosignal recording
- Multiple channels (4 or 8)
- Research-grade precision
- Open-source APIs
- Real-time data streaming
- Offline data recording
- Flash memory storage (optional)
- Additional sensors
- Multi-platform compatibility
Frequently Answers and Questions
What types of biosignals can the Mentalab Explore device record?
The Explore device can record EEG, EMG, and ECG signals.
How many channels does the Mentalab Explore device have?
Mentalab Explore comes in two models: one with 4 channels and one with 8 channels.
Can I use the Mentalab Explore device with my smartphone or computer?
Yes, the Explore device can be used with both smartphones and computers. It supports Bluetooth connection for real-time data streaming.
What is the maximum sampling rate of the Mentalab Explore device?
The default sampling rate is 250 sps (Samples Per Second). Optional rates of 500 or 1000 sps are available in beta phase.
How long can I record with the Mentalab Explore device before the memory is full?
The Explore device has 512 MB of optional flash memory, allowing for up to 8 hours of recording at 500 sps.
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