Synchronization with third-party devices is a common challenge when working with multiple sensor systems that complement each other.
In this tutorial you will learn how to use your biosignalsplux system to turn on the LED accessory at the beginning of an acquisition, creating a reference point for third-party devices to synchronize the start of a joint acquisition.
The concept is straight forward. Before the start of your acquisition, the LED will be turned off. Once the acquisition starts, the LED will be turned off. This change of LED state can be captured by third-party systems to identify when the biosignalsplux acquisition started, hence becoming a reference point for the synchronization.
For this setup, you will need the following products below:
In addition you need:
- 1x third-party system with light capturing capabilities (for example, a light sensor or a video camera)
Important Note This approach requires the use of a Digital I/O Port (Accessory Port) for the use of the biosignalsplux LED, which is only available in 8-channel biosignalsplux devices. This approach is not supported on 4-channel biosignalsplux hubs.
Step 1: Set up the LED
Connect your sensors to your biosignalsplux hub. If you need help identifying the right ports for your sensor, you can find further info in this article.
Connect the LED to the digital port of the biosignalsplux hub.
Place the LED where it can be clearly captured by your third-party’s light capturing device (light sensor or camera).
Step 2: Configure your hub in OpenSignals
Open OpenSignals and enter the device manager. Click on your biosignalsplux device to open all the available configurations and configure your sensors for acquisitions.
💡 Tipp Click on READ SENSORS of your device and OpenSignals will detect what sensors are connected to your hub and configure your sensor setup automatically. (Just make sure that your device is turned on.)
Once done, click on the circle next to DIGITAL (it must turn blue). This will configure your digital output to turn the LED on immediately at the beginning of the acquisition.
Step 3: Acquire your signals
First, double-check that the third-party system’s light capturing device can capture the LED clearly. Next, start the signal acquisition with your third-party system.
Once done, start the signal acquisition in OpenSignals by clicking on the record icon in the main menu.
The LED, which is turned off before the start of the acquisition, will turn on as soon as the acquisition starts. This change in LED state can be captured by your third-party hardware and used as a reference point that synchronizes the start of the joint acquisition.
Note that this process is suitable to help synchronizing the start of an acquisition. However, as the systems work independently, time drifts may still occur along the acquisition.
If you want to set multiple markers along the acquisition to help counteract this issue, you can control the LED state (on or off) manually during the acquisition in OpenSignals.
For this, press the circle next to the DIGITAL INPUT in the Information Bar as shown in the following examples.