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Element Icon Key Logger Element
Category: Input Registration AddIn: Base Elements
Creator: OkazoLab Team Scope: Parent Event
Owns Snippets: yes Usage: Input,Snippets

Actions aligned with epochs of the parent event

After OnsetThe element starts monitoring key presses and releases
Before OffsetThe element stops monitoring key presses and releases


Generic properties

NameDescriptionConstraintsValue TypeUpon Change
Input DeviceDefines the input device for key loggingenum
Logging ModeDefines what key events are recorded in the logenum
Column DelimiterDefines the column delimiter in the recorded key logString
Add Line BreaksDefines whether a line break is added at the end of each log recordBoolean
Autosave to DataReportIf true, the collected key log is automatically saved into the Data Report on the offset of the parent eventBoolean
Runtime Status
Custom ColumnsDefines a custom string that are added to the end of each log record. You can use this property to insert columns with extra information and sync markers (e.g. name of the current event) to the key log.String
Key LogString

+=== Properties inherited from clElement === Inherited properties of clElement
NameDescriptionConstraintsValue TypeUpon Change
Is EnabledIf set to false the element is completely omitted when the experiment is run.Boolean
TitleTitle of the element.String

Key Logger element saliently registers and logs all button presses and releases made within the parent event.


Use the Key Logger element, when you want to record all button events over a certain period in an experiment. The Key Logger elements carries logging saliently, so if you plan to handle button responses at run-time, you may prefer use either Button or HID input elements instead. The Key Logger element creates an internal text log, in which each record denotes a button event. The record is composed of 3 columns: time, button name and button state. Here is an example of the key log that recorded a press and subsequent release of the Space button.
Time (ms)Button nameButton State (1-down,0-up)Custom Columns
1472Space0 Event2

The column values are separated with a delimiter character that is defined by the Column Delimiter property. By default, a line break is added to the end of each record. The recorded log can be accessed by the Key Log property that returns a current log content as a single string.

Practical Use

Deploying the Key Logger element

  1. Select the event in your experiment, in which you want to log all button presses and releases.
  2. Add the Key Logger element to that event
  3. Browse the button element properties in the property panel
  4. Select the Input Device, for example, the system keyboard
  5. Think of how you are going save the recorded key log (one example is given in the next section)

Saving the recorded key log into Data Report

  1. Add the Key Logger element to a event
  2. Browse the button element properties in the property panel
  3. Select the Input Device, for example, the system keyboard
  4. Create a proxy variable linked to the Key Log property
  5. Open the After Offset snippet of the parent event
  6. Add the following code to the snippet:

Report=KeyLog; // send the recorded key log into the data report


  • The Key Logger works only with the primary input devices
  • The Key Logger can read only one input device
  • You can use multiple key logger elements in the same time, for example, for parallel logging of the keyboard and mouse buttons
  • Content of the key log is automatically cleared on every onset of the parent event
  • Key Logger element uses the DirectX button name convention, the same as in the Button element

  Name Size
- KeyLoggerIcon.png 7.00 KB

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