I found an issue that sampling rates between EEG signal and AUX signal which contain external trigger signals turn to be different values when transmitting them via the Lab Stream layer.

There are no Aux or extra channels available on Ganglion. The three 16 bit Aux channels on Cyton operate at the full 250 Hz rate. There is no bandwidth for this on the compressed 200 Hz Ganglion strea

There are no Aux or extra channels available on Ganglion. The three 16 bit Aux channels on Cyton operate at the full 250 Hz rate. There is no bandwidth for this on the compressed 200 Hz Ganglion strea

There are no Aux or extra channels available on Ganglion. The three 16 bit Aux channels on Cyton operate at the full 250 Hz rate. There is no bandwidth for this on the compressed 200 Hz Ganglion strea

I've checked every post under the Ganglion section of this forum looking for info regarding both trigger synchronization and SD card writing but I still don't understand what can be done. Anyway, her

Why do you need 4 different trigger values. Generally with P300 you just need to mark the presentation of the control or oddball stimuli. Both could be done with one sensor, and keeping track in your

@wjcroft, In my setup I would need about 4 different trigger values. Is that possible to have using a single photodiode somehow? Or does that mean I would need 3 photodiodes hooked up to the monitor?

@retiutut @wjcroft Just out of curiosity, would having another OpenBCI accessory for an external trigger system be a good idea?

I considered the photo diode option but since it takes away portability of the Cyton in a sense, i thought if using some external connections it’d make more sense to just do external triggering since

Please remember, SSVEP does not need highly precisely synchronized external trigger. Such triggers recorded with the EEG (in Aux channels), are mainly used in P300.

SSVEP does not need an external trigger, it's only required for P300 to get the precise timing between the onset of the control or oddball stimulus, and the P300 response. This timing allows averaging

If you are only doing SSVEP, you should not need external trigger capability. External trigger is more relevant for P300 / ERP.

One way to go, is to attach a photodiode-type device (with removable tape), to the corner of your monitor screen. Your experiment program can then "light up" a small square of pixels in this

I currently have a Cyton+Daisy setup with a Wi-Fi Shield. I would like to setup a triggering system, and after much research, I realise using an optoisolator between presentation system and the Cyton

Did you read the links about "external trigger"? One of your EEG channels or an Aux channel, is dedicated to recording the precise event timing of when the stimulus is presented to the subje

No, the Aux channel is recording your external trigger event timing. It's just a digital or analog leading / trailing edge that corresponds to when you present the oddball stimulus. You might possibly

The Aux channel or channels are recording the external trigger event. NOT "record the ERP". The EEG channels are recording the ERP. The external trigger, recorded in the Aux channel, corresp

ERP / P300 is usually done with an "external trigger" which is applied at the exact timing of your oddball stimulus (or control stimulus). This trigger value is recorded in the 'Aux' channel

the PIC32 / chipKIT processor. Because external trigger events recorded in the Aux channels have exact timing correspondence to the simultaneous EEG channels, they are the most accurate source of eve

ERP / P300 is usually done with an "external trigger" which is applied at the exact timing of your oddball stimulus (or control stimulus). This trigger value is recorded in the 'Aux' channel