This article applies to:
Experiment Author: Psychology Software Tools, Inc.
The Chronos Adapter for NIRx sample experiment illustrates how to use Task Events to send markers from the E-Prime experiment to the NIRx hardware.
The sample experiment presents a Stroop Task. Each trial presents the name of a color (e.g. "red") that is drawn in the same (congruent) or different (incongruent) ink color. The participant's task is to identify the ink color, ignoring the color word. The experiment sends the marker value 128 on congruent trials and 1 on incongruent trials.
The Chronos Adapter for NIRx provides access to 8 digital outputs (from Chronos to the NIRx hardware) as shown below:
When Chronos sends a marker on its first digital output, the NIRx hardware receives the value on Digital I/O bit 0 (pin 2). When Chronos sends a marker on its eighth digital output, NIRx receives it on digital I/O bit 7 (pin 9). To determine which NIRx bit(s) receive the Chronos output, do the following:
- Represent the integer marker being sent as a binary number.
- Map the binary number to Chronos's digital outputs to determine which outputs are set high (set to 1).
- Examine which NIRx pins map to the Chronos digital outputs that are set high.
For example, the sample sends the integer value 1 on incongruent trials:
- Integer value 1 equals the binary number 0000 0001 (Least Significant Bit is right-most bit).
- 0000 0001 sets the first Chronos digital output high; all other digital outputs are low.
- As shown in the table above, the first Chronos Digital Output maps to NIRx I/O bit 0.
The sample sends the integer value 128 on congruent trials :
- Integer value 128 equals the binary number 1000 0000.
- 1000 0000 sets the eighth Chronos digital output high; all other digital outputs are low.
- The eighth Chronos Digital Output maps to NIRx I/O bit 7.
NOTE: Extract all the files in the attached .zip file to the same folder. The sample experiment displays images that must be located in the same folder as the experiment.