Vertical Sync sensor

Buttonbox (2018)

2018 Buttonbox
Downloads
Buttonbox 2018 RuSocSci (Python package)

The Vertical Sync sensor is used on a computer/laptop monitor for time accurate visual presentation. The sensor measures screen brightness. It generates a BITSI trigger("A" = ON/light, "a" = OFF/noLight) when the amount of light is higher than the (customizable) threshold, which means that the exact onset of any visual stimulus can be marked. It can easily be attached to any screen with a pincher. The Vertical Sync sensor is connected to a computer with a usb connection.

BITSI Protocol

BITSI stands for Bits to Serial Interface.

Vertical Sync sensor
ASCII (rise/fall)	Code (rise/fall)	Light
A / a	65 / 97	ON / OFF

This means that when light falls on the sensor, a capital A will be sent to the serial port. A lowercase 'a' will be sent when the signal is deactivated(no light).

Output

The treshold for OFF is customizable and can be specified by sending a code Send code to specify the value for screen OFF.

EDIT howto

Port Settings

Serial port

Our hardware design allows to be connected to the computers USB and emulates a serial communication Port.

Baudrate	115200
Parity	None
Data bits	8
Stop bits	1
Flow control	None

USB-Com port

1.Connect the Vertical Sync sensor to your computer using the USB cable.

2.When you connect the Vertical Sync sensor, Windows should initiate the driver installation process (if you haven't used the computer with an Vertical Sync sensor before).

How to Check the Com Port settings(important!)

• From the Start menu, open the Control Panel.

• From the control panel, open the System window.

• From the system properties window, go to the Hardware tab and click the Device Manager button.

• From the Device Manager window, click Ports (Com&LPT). You should now be able to see which Com Port the USB adapter is assigned to.

• If the Com Port is 10 or higher, you will have to change it to a lower port.

• From the Device Manager window, click on USB Serial Port (Com#). Click the Port Settings tab of the USB Serial Port Properties window, and then click the Advanced button.

• In the Advanced Settings window, use the scroll input to select a Com Port (select 10 or lower). Change Receive (bytes) and Transmit (bytes) to 64. Change the Latency Timer to 1.

• Click the OK button.

Always connect the usb device to the same port and your settings will be remembered.

Software Settings

Neurobs Presentation

The experiment files needs a few settings for the device to work:

• In the settings tab: port -> input port -> 1 must be the device that identifies itself as "Arduino Uno" in the device manager. Note that the port must have a number not higher than 10 (COM1-COM10). Use re-enumerate if it is higher.
• Rate must be set 115200, Parity to None, Data Bits to 8 and Stop Bits to 1, Uncheck FIFO Interrupt.

Adding Marker

Example PCL code you can program a handle to send a marker:

#handle:
output_port OutputPort = output_port_manager.get_port( 1 );

Example to send a marker:

OutputPort.send_code(100); #create a marker

Python/PsychoPy

Download this site-package to use the buttonbox: rusocsci

or use in windows command 'pip install --upgrade rusocsci'

Example using buttons from the buttonbox in Python:

#!/usr/bin/env python

# import the rusocsci.buttonbox module
from rusocsci import buttonbox 

# make a buttonbox
bb = buttonbox.Buttonbox()

# wait for a single button press
b = bb.waitButtons()

# print the button pressed
print("b: {}".format(b))

Example using markers with the buttonbox in Python:

#!/usr/bin/env python

# import the rusocsci.buttonbox module
from rusocsci import buttonbox 

# make a buttonbox
bb = buttonbox.Buttonbox()

# send a marker
bb.sendMarker(val=100)    #This is your marker code, range code 1-255

Example using BITSI extended in Python:

#!/usr/bin/env python

# import the rusocsci.buttonbox module
from rusocsci import buttonbox 

# make a buttonbox
bb = buttonbox.Buttonbox()

# select a function
bb.sendMarker(val=(ord(X)))    #select pulse time
bb.sendMarker(val=2)           #set time of dureation pulse to 2ms

bb.sendMarker(val=(ord(M)))    #select marker out
bb.sendMarker(val=115)           #set marker value 115

Example using BITSI extended analog read in Python:

#!/usr/bin/env python

# import the rusocsci.buttonbox module
import serial

# make a buttonbox
ser = serial.Serial("COM2", 115200, timeout = 0.10 )
ser = serial.Serial("/dev/ttyUSB0", 115200, timeout = 0.10 )

while True:
	ser.write('A1')
	ser.flush()
	x = ser.readline()
	visual.TextStim(win, text=x).draw()

	# black screen for 1000 ms
	win.flip()

	key = event.getKeys()
	try:
		if key[0]=='escape':
			break
	except:
		continue

Example using the Buttonbox in PsychoPy:

#!/usr/bin/env python

# import psychopy and rusocsci
from psychopy import core, visual 
from rusocsci import buttonbox

## Setup Section
win = visual.Window(monitor="testMonitor")
bb = buttonbox.Buttonbox()
text = visual.TextStim(win, "Press a button on the buttonbox")

## Experiment Section
# show text
text.draw()
win.flip()
# wait for response
b = bb.waitButtons()
# show response
text.setText("you pressed: {}".format(b))
text.draw()
win.flip()
core.wait(5)

## Cleanup Section
core.quit()

For more documentation click here: http://pythonhosted.org//RuSocSci/index.html

Matlab

Example using markers with the Buttonbox in Matlab:

Download the file Bitsi.m from the DCCN website: https://intranet.donders.ru.nl/index.php?id=bitsim0
Make sure to have this file in your Matlab path.

% At the start of your script, create the buttonbox serial object
bb = Bitsi("COM2");
% other code
        :

BITSI simple mode:

% This example is for an EEG system sampling at 500Hz samplerate.  
% at the start of your script, reset marker
samplerate = 500;
pulseLen = 2000/samplerate;
bb.sendTrigger(0);
% send a marker
val = 1;                                     % val: this is your marker code, range code 1-255
bb.sendTrigger(val);
java.lang.Thread.sleep(pulseLen);    % wait long enough for the EEG system to capture the trigger, i.e., 2000/samplerate ms
% reset marker
bb.sendTrigger(0)                 % Note: if resetting the marker is not possible at this moment in code, you can decide to do this later as long as it has taken place long enough before the next marker has to be sent.

BITSI extended mode:

samplerate = 500;
pulseLen = 2000/samplerate;
% select a function
bb.sendTrigger(uint8('X'));   % select pulse time
bb.sendTrigger(pulseLen);             % set time of duration pulse to (2000/samplerate) ms
 
val = 1;                                     % val: this is your marker code, range code 1-255
bb.sendTrigger(uint8('M'));  % select marker out
bb.sendTrigger(val);              % val: this is your marker code, range code 1-255

% At the end of your script, close the buttonbox serial object
    :
bb.close();