biosignalsplux devices are designed for multi-sensor acquisitions with each of the devices supporting up to 4 or 8 sensors depending on the device you’re using.
However, sometimes, one device is not enough to cover all the sensors needed and you might like to use more.
Find out more about the possibilities in this article.
Up to 8 Sensors Using One Device
You can use up to 8 sensors of your choice using an 8-channel biosignalsplux hub. For this, connect the sensors to any sensor port of your choice (green).
You can connect a common reference electrode for all your electrode-based sensors to the yellow port and biosignalsplux accessories to the red accessory port.
Up to 24 Sensors Using Three Devices
Our OpenSignals software supports real-time signal acquisition via Bluetooth & visualization using setups of up to 3 biosignalsplux hubs and up to 24 sensors.
For this, connect the sensors to the numbered sensor ports (green) of your 8-channel biosignalsplux hubs and your synchronization accessories to the accessory port (red).
For further information, follow our article “How can I synchronize two or more biosignalsplux hubs in OpenSignals?“.
Using More than 3 Devices or 24 Sensors
While synchronized acquisitions using up to 3 devices are still supported via Bluetooth in OpenSignals, using more than 3 devices is limited by the number of stable Bluetooth connections that can be handled by your computer’s Bluetooth module.
For this setup, we recommend using the biosignalsplux’s data logging features and our OpenSignals software to configure the data recording onto each device’s internal memory instead (data logging).
You can purchase this feature separately if it is not included in your biosignalsplux kit.
For this, connect the sensors to the numbered sensor ports (green) of your 8-channel biosignalsplux hubs and follow the instructions below for the option that suits you best.
The data logging features allow you to select one of two available start conditions for your data acquisition, as explained in detail in this article:
- Schedule Data Logging at a Selected Time (e.g. 2pm) (compatible with 4-channel & 8-channel devices only)
- Start Data Logging through Trigger Input Signals (compatible with 8-channel devices only)
Select one of the available methods below for your setup and configure each of your your devices accordingly for your signal acquisition. After the acquisition, you can download the data from your devices as explained in this article.
Schedule Data Logging at a Selected Time
This option is compatible with both 4-channel & 8-channel biosignalsplux hubs.
This data logging feature allows you to select a specific time at which the data logging starts for all your devices.
We recommend this option if you are using biosignalsplux hubs without any possibility to use synchronization or trigger input accessories, i.e. no physical connection between the hubs is available to ensure their synchronization.
This can be the case, for example, when using 4-channel devices (no support for such accessories) or when the participants of your studies are moving freely without any possibility to connect their devices.
We recommend the following workflow:
- Turn on all your biosignalsplux devices
- Use OpenSignals schedule your acquisition for your first biosignalsplux hub at a specific time*
- Repeat the scheduling process for the remaining biosignalsplux devices
- Record your signals
- After the acquisition, download the data from all biosignalsplux devices individually to your computer
* ensure that the start time is distant enough to leave you enough time to set up the remaining devices
This setup is both compatible with biosignalsplux only setups or in combination with third-party equipment.
Start Data Logging through Trigger Input Signals
This option is only compatible 8-channel biosignalsplux hubs.
This setup requires a physical connection between biosignalsplux hubs and third-party equipment through the hub’s accessory port, which is only available on 8-channel hubs.
This data logging feature allows you to start the acquisition of your devices once an external trigger signal is received after which the data logging starts for all your device.
We recommend this option whenever you’d like to use third-party equipment to control the acquisition and if a physical connection between your third-party equipment and biosignalsplux hubs can be established.
This can be the case when you are running a third-party software to control the acquisition using multiple devices, both biosignalsplux and non-biosignalsplux devices, and you want to trigger a common starting point across all your devices.
We recommend the following workflow:
- Turn on all your biosignalsplux devices
- Use OpenSignals to configure your acquisition to start after receiving a trigger input signals for your first biosignalsplux hub
- Repeat the process for the remaining biosignalsplux devices
- Record your signals
- After the acquisition, download the data from all biosignalsplux devices individually to your computer
This setup is both compatible with biosignalsplux only setups or in combination with third-party equipment, although it is more commonly used in setups with third-party equipment.
Frequently Asked Questions (FAQs)
Why is it important to synchronize my devices?
Synchronization is important to ensure that all the sensor data recorded from different devices is recorded at the same time to avoid time drifts between devices.
Individual devices have slight shifts between their internal clocks which can accumulate to time drifts between devices throughout the acquisition, especially during long-term acquisition.
Synchronization serves to synchronize the internal clocks of the individual devices to ensure that they measure signal samples at the same shared time.
Do I have to use the synchronization accessories for my acquisition?
Data acquisition without synchronization is possible, but we recommend using synchronization accessories whenever possible for optimal results.
Note that while setting a common start time for all devices minimizes the risk of having signal drifts due to different start times, it does not guarantee a synchronization throughout the entire acquisition.
Can I do synchronized setups with 4-channel hubs?
Unfortunately, no. Synchronized setups require the use of synchronization accessories that must be connected to the accessory port of your hub.
Accessory ports (highlighted in red in the images above) are only available on 8-channel hubs and not on 4-channel hubs.
Can I use my biosignalsplux device to generate a start trigger signal?
Yes, this is possible using 8-channel biosignalsplux devices.
In the device’s configuration panel, you can find two different options to do so:
- Using a single trigger signal at the start of the acquisition (recommended if you only need to generate a start signal)
- Using a continuous synchronization signal (0.5Hz rectangle signal) (recommended if you are also using multiple biosignalsplux devices)
The output signals is send via the hub’s accessory port.
Can I receive start trigger signals from third-party devices?
Yes, this is possible through the biosignalsplux’s accessory port available on 8-channel devices which allows you to receive 0-3V input trigger signals from third-party devices.
Do you provide custom adapters for third-party solutions?
Yes, our R&D team can create custom adapters to connect our biosignalsplux units to your third-party hardware.
Contact our support to provide technical information about your system to receive a free quotation about the costs of a custom adapter.
For our evaluation, we need primarily the following information about the third-party system:
- Brand
- Model number
- Connector type
- Technical documentation (e.g. datasheet)
I don’t need many sensors but I may need multiple devices. What would I do?
The selection criteria above are based on the number of sensors as it is the most common driver of selecting the right setup.
However, sometimes, the focus is rather set on the number of needed devices, for example, if you’d like to record only 4 sensors but from 4 different study participants individually.
If your study participants are all located at the same place throughout the acquisition, for example, around the same desk, you may consider the connecting all participants to the same hub.
Otherwise, we recommend that each participant has their own data collection (or data logging) hub even if the full number of supported sensors is not used for each hub.
