Welcome Guest, you are in: <root>Elements • Login

Page History: Key Logger Element

Compare Page Revisions

8 7 6 5 4 3 2 1 0 Current 8 7 6 5 4 3 2 1 0

« Older Revision - Back to Page History - Newer Revision »

Page Revision: 2015/08/18 14:52

Key Logger element registers all button presses and releases in the parent event and saves them into an internal text log.

Table of Contents [Hide/Show] Actions aligned with epochs of the parent event Properties     Generic properties Description Practical Use     Saving the recorded key log into Data Report Notes

Description ¶

You should use the Key Logger element, when you need to record all button events over a certain period in an experiment. The Key Logger elements carries logging passively, so if you plan to handle button responses at run-time, you may prefer either Button or HID input elements instead. The Key Logger element creates an internal text log, in which each record denotes a button event. Each records 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 name	Button State (1-down,0-up)
1034	Space	1
1472	Space	0

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 ¶

1. Define 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

Notes ¶

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