Event Triggers

Here is a quick reference section on integrating Mentalab Explore+ hardware with third-party solutions.

Event markers allow you to timestamp important points in your ExG signal. There are three kinds of event markers presented in the diagram below. The first two are hardware-generated. The third is software-generated.

Mentalab trigger diagram — Diagram outlining trigger options available with Mentalab hardware.

Button press (Hardware)

You can create an event marker in your ExG recording by pressing your Explore+ amplifier’s button. Button press markers have numbered codes between 0 and 7. The event marker whose code is 7 will be followed by an event marker whose code is 0. For more information, see the Button Command Guide.

TTL pulse (Hardware)

You can use TTL pulses to generate event markers. These markers have a latency of around 200 microseconds. To do this, you will need three pieces of hardware:

A USB to TTL pulse generator, called the Mentalab trigger stick¹.
A trigger isolator: a specialized piece of hardware that prevents sudden noise.
A USB to USB-C cable. This will connect the trigger stick to the trigger isolator.

The trigger stick connects to the USB port of your host machine. The isolator connects to Explore’s USB-C port.

We will also release 8 bit trigger solution very soon. Contact the Mentalab team to purchase a set-up.

The Mentalab trigger stick is active low, this means it triggers the amplifier when the pulse goes from high to low.

Once configured, you can use any serial library, such as Python’s pyserial, to generate 10 μs pulses from your host machine to your Explore+ amplifier.

TTL pulses are recorded in your amplifier’s marker file with code in_0. These markers will behave the same as push button markers.

Software marker

You can generate event markers using Mentalab software (Explore Desktop and the APIs), or using external software, like LSL, OpenViBE, and psychopy.

Explore Desktop, explorepy, and exploreAndroid generate markers with numbered codes between 0 and 65535. These markers are recorded in the marker file with sw_ prefixed to the numbered marker code.

External software markers have named codes – Strings. These markers will be recorded in the marker file with ext_ prefixed to their named code.

For more information or support, do not hesitate to get in contact at: support@mentalab.com

Other TTL pulse generators are available for custom set-ups. ↩︎