This article applies to:
E-Prime 3.0
Chronos
Detail
Experiment Author: Psychology Software Tools, Inc.
The Chronos Adapter for BioSemi sample experiment illustrates how to use Task Events to send markers from the E-Prime experiment to the BioSemi receiver.
Abstract
The sample experiment presents a Visual Oddball Task: each trial presents the letter "O" or "X" and the participant's task is to distinguish between these letters. 80% of the trials present the letter "O" and 20% of the trials present the letter "X". The experiment sends the marker value 1 when the letter "O" is shown and the value 32768 when the letter "X" is shown.
The Chronos Adapter for BioSemi provides access to 16 digital outputs (from Chronos to the BioSemi receiver and eight digital inputs (from the BioSemi receiver to Chronos) as shown below:
This sample experiment illustrates the digital output functionality. When Chronos sends a marker on its first digital output, the BioSemi receiver receives it on Digital Input #1 (pin 1). When Chronos sends a marker on its sixteenth digital output, the BioSemi receiver receives it on digital input #16 (pin 16). To determine which BioSemi receiver digital input receives a trigger value sent from Chronos, do the following:
- Represent the integer marker being sent as a binary number (see INFO: Choosing a marker value to send from E-Prime to an external device [42529] for more information on integer and binary numbers).
- Map the binary number to Chronos's digital outputs to determine which outputs are set high (set to 1).
- Examine which BioSemi receiver digital inputs map to the Chronos digital outputs that are set high.
For example, the sample sends the integer value 1 when the stimulus = the letter "O":
- Integer value 1 equals the binary number 0000 0001 (Least Significant Bit is the 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 Outputs maps to BioSemi receiver Digital Input 1.
The sample sends the integer value 32768 when the stimulus = the letter "X":
- Integer value 32768 equals the binary number 1000 0000 0000 0000.
- 1000 0000 0000 0000 sets the sixteenth Chronos digital output high; all other digital outputs are low.
- The sixteenth Chronos Digital Output maps to BioSemi receiver Digital Input 16.
NOTE: To configure the E-Prime experiment to receive signals sent from the BioSemi receiver to one of the Chronos adapter's eight digital inputs, create an InputMask for the Chronos device that looks for the pseudo button responses 9, A, B, C, D, E, F, and/or G, which map to Chronos digital inputs 9, 10, 11, 12, 13, 14, 15, 16. See Section 6.2 Pseudo Buttons of the Chronos Operator Manual and DEVICE: How To: Synchronize E-Prime with an incoming marker/press via an Input Mask [34380] for details.
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.
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