Hello. I got some problems in placing event markers with real time EEG. My experiment requires touchpad, and event markers are needed for data analysis. External trigger using hardware is not suitable

Richard @retiutut just tried a test wiring his digital trigger from an Arduino to Cyton, using the opto isolator as shown at the end of the external trigger doc.

Most likely your trigger is being detected / placed wrong.

Recall that we are now suggesting you connect the trigger in "analog read mode", NOT in "digital read mode". There is no extra wiring required, just connect your trigger source to

Do I need to do any extra wiring to connect digital trigger at D12/D 13?

There may be some distortion in using "digital read mode" for the PIC32 input pins. Please switch over to analog read mode. Then do some signal processing on the Aux channel values: for exam

My Professor suggesting to use D11/D12 for external trigger. These are suitable for both analog and digital input, right? Do I need to do any extra wiring to connect digital trigger at D12/D 13?

"Then do some signal processing on the Aux channel values: for example PIC ADC values less than threshold X equals trigger off."

There may be some distortion in using "digital read mode" for the PIC32 input pins. Please switch over to analog read mode. Then do some signal processing on the Aux channel values: for exam

I didn't connect any external resistance for digital external trigger.

Rafia, hi. I just ran across a comment (by chance) on our internal staff Slack channel by Richard @retiutut. From early October. He is seeing some odd delays with the Cyton PIC32 Digital Read Mode, th

Please try removing the suggested series resistor and see if that works. Your length of trigger pulse should be irrelevant, as long as it is registered by a few sample times. If noise appears in the E

Trigger events are signaled by the ON transition of the trigger wire. NOT by the length. As long as your software can detect the leading edge, that is all that matters. Length of trigger (as long as i

Hmm, 300ms is 1/3 of a second. 900ms is almost a complete second. Your trigger event time is indicated by the leading edge of the trigger signal, not the LENGTH of the trigger. I don't understand. Are

Now the problem is solved. I had to increse the PW of my external trigger. At previous, it was around 300 ms . Now around 900 ms.

Since the Cyton is battery powered, there are no "ground loops" possible. The only reason I mentioned the 100K on the logic pin, was to reduce any potential capacitive / inductive coupling t

There IS NO Vdd connection required to send an external trigger to the Cyton.

All ADC systems only sample the analog stream at specific point. It's possible that your trigger signals are missing the sample window. Seems important for you to TURN ON the trigger signal somewhat i

You already said that, "Tone ground to Cyton ground". The trigger signals are voltage logic levels, so all you need are the signal and ground wires.

third pic is trigger pulses with eeg . 2nd pic is trigger . first pic is only eeg which is showing high micro volt. Confused. Is it okay ?