Support for Bits #

A special version of Psykinematix supports the Bits# device from Cambridge Research Systems (CRS). Named Psykinematix # (Sharp), it is exclusively available from Namoto Trading in Japan and from Cambridge Research Systems in the rest of the world.

What is the Bits#?
Configuring the Bits#
Calibrating the Bits# display
Running Experiments with Bits#
Troubleshooting

What is the Bits#?

The Bits# (Bits sharp) is a high dynamic range, calibrated visual stimulator and frame-synchronous data acquisition system. Bits# (Bits Sharp) is the successor to the ubiquitous CRS ViSaGe, VSG2/x and Bits++ systems from Cambridge Research Systems and provides essential stimulus calibration and synchronisation features for vision research.

Psykinematix # supports the following Bits# features:

Before configuring the Bits#, make sure to select the display connected to the Bits# from the Display Preferences and specify the resolution and frame rate to be used:

The display attached to the Bits# should typically appear as "External (1)" in the Stimulus Display popup menu. If it is not listed, then make sure to:

Configuring the Bits#

The Bits# can then be configured from the USB section of the I/O Preferences.

 

The list of currently connected USB-HID devices that can be used as response devices is available from the Response Devices Preferences. Any of these devices can be used to provide the subject's response, trigger the next trial or simply terminate a stimulus presentation. However, only those with a checked "Active" box will be available to your experiments, and the ones with the checked "Default" box will be set as default response device when creating new experiments without specifying any device. The default device can be changed on an experiment basis in the Experiment properties under the Input/Output tab. When using multiple devices that act as keyboard, it is important to specify as default keyboard the one used by the experimenter to start and stop an experiment with the ESC keypress.

If some devices have been disconnected or connected while running Psykinematix, it is important to update the device list by clicking on the blue circular arrow (Note however that some USB devices may need to be plugged into a powered USB hub to properly work). Some unknown devices may appear in this list: they are likely wireless devices that can be recognized through a USB receiver. Be sure to uncheck the "Active" box for each of these "phantom" devices. Some trial-and-error troubleshooting may be required to identify these "phantom" devices.

Clicking on the USB, Serial or Network icon opens a configuration window that lists all recognized devices of this type. If some devices have been disconnected or connected while running Psykinematix, it is important to update the device list by clicking on the blue circular arrow . Select the device you want to use, customize its properties, and click on the "Start" button to test the device. Once tested, click on the "Stop" button to return to the device list. If the device test is successful, its status shown in the last column change to a blue checked indicator . Other indicators have the following meaning:

Device OK: the device has been detected, but has not been tested yet;
Missing device: the device has been previously used, but it is not available anymore;
Failed Test: the device failed to be tested;

After successfully testing a device, you can then check its "Enable" box to make it available by default to any new experiment. All devices checked in the "Enable" column will appear in the Experiment Input/Output settings where they can be removed if needed. These enabled devices are also those selectable from the "Trigger" pop-up menu in the "Control Settings" palette available for most stimuli.

USB devices:

Psykinematix supports the ioLab button box a USB input device that allows high accuracy response time measurement. Note that support for the ActiveWire device is now deprecated due to the GNU General Public License in use by the only Mac OS X compatible ActiveWire driver and interfaces.

When testing the ioLab button box, each of the 8 buttons can be configured to be enabled during the experiment. The status of each button is updated in real-time whenever it is pressed or released during the test. A clock drift estimate is also provided to verify the accuracy of the button box internal clock. The provided key names are the ones that should be used to indicate the inputs to perform an action. Similarly to HID devices, button box devices can be used to perform the following actions: provide subject's response, trigger the next trial or simply terminate a stimulus presentation.

Note as well that the ioLab button box can trigger "Trial Alarms" at regular intervals which are detected as "TA" inputs by Psykinematix. The first time the experiment waits for a "TA" input automatically starts the "Trial Alarms" timer. This feature is particularly useful to simulate a TTL input or present stimuli at very regular intervals. The value of the built-in variable TAPERIOD specifies the period of the trial alarm in seconds, and should be defined in the independent variable table of the Experiment Control Settings.

Serial devices:

Psykinematix supports generic RS-232 serial communication through the use of USB-to-serial adapters (connected to another PC or other piece of equipment), as well as specialized devices like the Cedrus RB Series Response Pads that also use serial communication through a built-in USB-to-serial adapter. The type and use of the selected device should be properly specified to indicate the function of the device in your experiments: "Remote PC" or "Cedrus" for the type, "Trigger In", "Trigger Out" or "Button Box" for the use. Other settings are standard serial settings:

"Cedrus" Type:

Psykinematix supports the Cedrus RB Series Response Pads that act as button boxes and allows high accuracy response time measurement. Psykinematix also supports the Lumina Response Pads for fMRI through the Cedrus Lumina LP-400 controller that can convert a TTL trigger signal provided by a fMRI scanner to a button input.

Up to 8 buttons are available on Cedrus response pads. When testing the devices, the status of each button (including the TTL input from the Lumina controller) is updated in real-time whenever it is pressed or released. A clock drift estimate is also provided to verify the accuracy of the button box internal clock.

 

The provided key names are the ones that should be used to indicate the inputs to perform an action. Similarly to HID devices, button inputs from Cedrus devices can be used to perform the following actions: provide subject's response, trigger the next trial or simply terminate a stimulus presentation.

 

Calibration Devices

Display calibration devices are photo-sensors that are mounted on the surface of the display screen and connected to the computer via a USB interface or some other link. During the calibration process they measure the light properties of test patterns that are displayed on the screen in sequence, and then send the data to the computer. Three types of devices are of interest for display calibration: photometers, colorimeters, and spectroradiometers.

Psykinematix supports in particular the following colorimeter devices:

Running Experiments with BIts#

If you already created your experiment to run on a regular setup without a Bits#, then simply follow these steps to ensure that your experiment will run smoothly with the Bits#:

- Edit the "Display" properties of the experiment and specify the display, resolution, calibration configuration and video mode (Mono Bits# or Colour Bits#) to be used with the Bits# as ilustrated below:

Note that a warning will be emitted at run-time if you select a chromatic mode not compatible with the mode targeted by the calibration configuration.

- After testing and configuring the Bits# from the I/O USB Preferences, enable the Bits# by clicking its Enable checkbox:

- Once the Bits# is enabled in the I/O USB Preferences, it should be specified as an Input/Output USB or Button Box device for the experiment as illustrated below:

The Button Box device should be specified anytime a CB6 or CT6 IR Response Box is used by subjects to provide their responses.

This critical error will be emitted at run-time If you fail to specifiy the Bits# device:

The selected chromatic mode (Mono Bits#) requires a 'Cambridge Research Systems Bits#' (USB device) specified in the Input/Output section of the Experiment's properties!

This critical error will be emitted at run-time If you fail to specifiy the Bits# device as Button Box:

Error in event <event name>: No 'Button Box' input device has been set up in this experiment!

Troubleshooting

Problem: Psykinematix appears to be frozen (with spinning) beachball.

Solution: Corrupted communication with the Bits# can sometimes freezes Psykinematix. Force-quitting Psykinematix and powering off and on the Bits# should restore Psykinematix stability.

Problem: Logged error message "Failed to switch Bits# to 'Mon/Colouro Bits#' chromatic mode!"

Solution: make sure the Bits# is in CDC mode (by ejecting the VISAGE disk colume and power off and on the Bits#)

Failure to test the Bits#

Solution:

Try the following in this order::

1. Unplug and plug the Bits# again
2. Relaunch Psykinematix
3. Restart the computer

Graphic Card Compatibility

Some LUT related may interfer with the Bits# T-Lock. Because Apple driver for NVIDIA graphics cards appears to permanently enable temporal dithering, the Bits# may not work out of the box if you use Mac OS 10.5 or 10.6 and NVIDIA graphics. Psykinematix provides several work-around to this problem:

- disable the temporal dithering if allowed by the graphic card (requires the installation of NVInject to modifify the graphic card configuration)

- try to adjust the Identity LUT to compensate for the temporal dithering.

© 2006-2013 KyberVision Consulting, R&D. All rights reserved.

Mac, Macintosh, Mac OS and QuickTime are trademarks of Apple Inc., registered in the U.S. and other countries. Cambridge Research Systems, Bits#, and the names of Cambridge Research Systems products referenced herein are either trademarks and/or service marks or registered trademarks and/or service marks of Cambridge Research Systems. OpenGL is a registered trademark of Silicon Graphics, Inc. All other brand and product names are trademarks of their respective holders. Any omission of such trademarks from any product is regretted and is not intended as an infringement on such trademarks.