The Extender’s hardware triggering feature allows you to mark external events with high accuracy for further analysis. The input trigger pulses are injected into the headset data stream so that the latency between trigger and sample is minimised to be within 1 sample. There is a stable fixed delay of 60ms from trigger input to appearing in the data stream.
EMOTIV has provided a custom 1m trigger cable with every extender. The cable has two tinned wires red and black that can be connected to an external stimulus, the input polarity of the trigger is reversible because the opto-isolated trigger input has back to back output diodes utilising the Vishay VOL628A (datasheet). This part requires a minimum of 1mA forward current and maximum of 60mA. The input design has an internal limiting resistor of 1kOhm. The trigger input voltage is between 2.5-15V and driven directly off a parallel port or from an arduino. Please see below Arduino examples:
Trigger Cable
The Extender trigger input requires a 2.5mm audio connector which has an outer diameter of less than 6.8mm to fit into the socket.
EMOTIV has provided a 1m trigger cable with every Extender. It features the required low profile connector on one end and has two tinned wires (red and black) for connecting to your trigger source. We have provided some links with examples of arduino scripts.
- 1s Pulse: generates 100 pulses at 1s intervals.
- Serial Triggering: Sends a trigger pulse each time the trigger character is received on the arduino serial port
- MATLab
