Mark M. Span

Working at research support BSS, University of Groningen

EVTPlugins, rewrite by Martin

pyevt - A python binder for the Event-Exchanger EVT-2 USB hardware

1. About

This repository contains the code to communicate with EVT-2 USB-devices, developed by the Research Support group of the faculty of Behavioral and Social Science from the University of Groningen. This code was originally written by Eise Hoekstra and Mark M. Span and is now maintained by Martin Stokroos

The EVT-2 is an event marking and triggering device intended for physiological experiments. pyevt is a Python module to communicate with EVT-2 hardware (+derivatives).

2. Install

Install pyevt with:

pip install pyevt or pip install --user pyevt on managed computers.

3. Dependencies

The pyevt-library uses the HIDAPI python module to communicate over USB according the HID class.

4. Device Permission for Linux

In Linux (Ubuntu), permission for using EVT (HID) devices should be given by adding the next lines to a file, for example named: 99-evt-devices.rules in /etc/udev/rules.d:

# /etc/udev/rules.d/99-evt-devices.rules

# All EVT devices
SUBSYSTEM=="usb", ATTR{idVendor}=="0004", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0008", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0009", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0114", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0208", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0308", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0408", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0508", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0604", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0808", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0909", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="1803", MODE="0660", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="1807", MODE="0660", GROUP="plugdev"

The user should be a member of the plugdev -group.

Check with:

$ groups username

If this is not the case, add the user to the plugdev group by typing:

$ sudo usermod -a -G plugdev username

5. Python coding examples

from pyevt import EventExchanger

myevt = EventExchanger()
# Get list of devices containing the partial string 'partial_device_name'
myevt.scan('partial_device_name') # The default is 'EventExchanger'.

# Create a device handle:
myevt.attach_name('partial_device_name') # Example: 'EVT02', 'SHOCKER' or 'RSP-12', etc. The default is 'EventExchanger'.

myevt.write_lines(0) # clear outputs
myevt.pulse_lines(170, 1000) # value=170, duration=1000ms

# remove device handle
myevt.close()

# connect RSP-12
myevt.attach_name('RSP-12')
myevt.wait_for_event(3, None) # wait for button 1 OR 2, timeout is infinite.
myevt.close() # remove device handle

6. License

The evt-plugins collection is distributed under the terms of the GNU General Public License 3. The full license should be included in the file COPYING, or can be obtained from

http://www.gnu.org/licenses/gpl.txt

This plugin collection contains the work of others.

7. Documentation

Information about EVT-devices and OpenSesame plugins:

https://markspan.github.io/evtplugins/

The BSS Research Support OpenSesame Plugin Collection

An OpenSesame plugin collection for sending stimulus synchronization triggers and response collection through Event Exchanger (EVT-2) USB-devices.

Contributions: This code is based on the work of Eise Hoekstra and Mark M. Span. The code is debugged and rewritten for OpenSesame 4 by Martin Stokroos.

1. About

The BSS Research Support OpenSesame Plugin Collection for use with Event Exchanger (EVT-2) USB-devices.

EVT-devices and the associated plugins are developed by the Research Support department from the faculty of Behavioural and Social Sciences from the University of Groningen.

The currently supported OpenSesame version is: 4.

The following plugins are available:

plugin	Description	OpenSesame back-end	operating system	Status
evt_trigger	plugin for event exchanger EVT-2,3 and 4 variants for generating triggers	PyGame, PsychoPy	Windows	ok
response_box	plugin for all of the RSP12x button response box variants with 1-8 buttons	PyGame, PsychoPy	Windows	ok
rsp_pygame	plugin for RSP12x button response box variants with 1-8 buttons	PyGame	Windows, Linux	ok
tactile_stimulator	plugin for the Electrotactile Stimulator (SHK-1B) 0-5mA	PyGame	Windows	ok
vas_evt	A Visual Analog Slider plugin controlled via an encoder knob connected to the EVT-2	PyGame	Windows	planned
vas_gui	A Visual Analog Slider plugin controlled via the PC-mouse on a predefined canvas (sketchpad)	PyGame	Windows, Linux	Mouse response not ok in Linux.
rgb_led_control	plugin for multi-color LED response boxes	PyGme	Windows	not validated

Package dependencies

The plugins are dependent on the Python module pyevt and the underlying hidapi package.

https://pypi.org/project/hidapi/

pyevt and hidapi are installed from the Python Console in OpenSesame with the single command:

!pip install --user pyevt

NOTE: Currently, the plugin package is released as pip package in a test environment. Clone this repository and copy the plugins manually into your OpenSesame python package folder or temporary install from the command line in OpenSesame 4 with:

!pip install --user hidapi
!pip install --user --index-url https://test.pypi.org/simple/ pyevt
!pip install --user --index-url https://test.pypi.org/simple/ evt-plugins

Environmental settings

By default, the OpenSesame 4.0 plugins are installed as python site-package and automatically loaded at the startup. When the plugins are located somewhere else, add your path to the python-path of OpenSesame in the environment.yaml file in the OpenSesame program directory (The OPENSESAME_plugin_PATH is old style). See for the instructions here: https://rapunzel.cogsci.nl/manual/environment/

2. Plugin Descriptions

evt_trigger

Existing modes:

Clear output lines
Write output line
Invert output lines
Pulse output lines

response_box

Collects responses from a 1 to 8 button RSP-12x response box.

After the prepare phase of the plugin, a workspace variable connected_device_plugin_instance_name is created to check if the actual tactile-stimulator device is really detected and connected to the plugin.

rsp_pygame

This response-box plugin works for EVT devices as well for joystick devices. It makes use of the pygame joystick API and is platform independent.

tactile_stimulator

The tactile_stimulator plugin operates in two modes. Usually two instances of this plugin are used in the OpenSesame experiment. Mode-I, the Calibration-mode should always precede the Stimulate-mode. In Calibration-mode the upper limit of stimulus-current threshold is set between 0 and 5mA rms. In the Stimulate-mode, a percentage of the stimulus-current upper limit is set to be applied to the subject. The Calibration-mode can be used standalone for instance to precondition the subject. The pulse duration can be extended up to 2000ms.

Here below follows a list of variables that appear in the OpenSesame variable inspector when using the tactile_stimulator plugin:

variable name	description
`tactstim_calibration_perc`	The percentage of the slider setting for the stimulus current of up to 5mA rms max.
`tactstim_calibration_milliamp`	The calibration value of the stimulus current in mA’s. This is the max. current applied to the subject.
`tactstim_calibration_value`	The byte value representation of the calibrated current.
`tactstim_pulse_milliamp`	The actual current in mA’s, applied to the subject when pulsing.
`tactstim_pulse_value`	The actual byte value representation that is sent to the tactile stimulator.
`tactstim_pulse_duration_ms`	The pulse duration time in ms.
`tactstim_time_last_pulse`	Unique time stamp in seconds from the moment of the shock.

vas_evt

A Visual Analog Slider plugin controlled by an EVT rotary or linear encoder. The vas_evt plugin does not work standalone, but requires a linkage to a custom designed sketchpad screen.

vas_gui

A Visual Analog Slider plugin. The vas_gui plugin does not work standalone, but requires a linkage to a custom designed sketchpad screen with an analog slider design!

Here below is the list of the variables that will appear in the OpenSesame variable inspector when using the vas_gui plugin:

variable name	description
`vas_response`	This value is the reading from the VAS object, ranging from 0 to 100.
`vas_response_time`	this is the repsonse time in ms. The value -1 means that the timeout period was reached.

rgb_led_control

This plugin works for the RSP-LT device, a response-box with RGB-controlled LED buttons.

3. LICENSE

The evt-plugins collection is distributed under the terms of the GNU General Public License 3. The full license should be included in the file COPYING, or can be obtained from

http://www.gnu.org/licenses/gpl.txt

This plugin collection contains the work of others.

4. Documentation

Installation instructions and documentation on OpenSesame are available on the documentation website:

http://osdoc.cogsci.nl/

Evt-plugin information:

https://markspan.github.io/evtplugins/

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