SR Box
Overview
- About the srbox plug-in
- Screenshot
- Setting the device name
- Requirements
- Download and installation
- Using the SR Box from Python inline code
About the srbox plug-in
The serial response (SR) box is a button box, specifically designed for response collection in psychological experiments. The original version, developed by Psychology Software Tools, has 5 buttons, 5 lights, and is connected to the PC trough the serial port. There are also SR Box compatible devices by other manufacturers, which may differ in the number of buttons and lights and often use a USB connection, which emulates a serial port. The advantage of using an SR Box is that response times can be measured more accurately than using a garden variety keyboard. Of course, it also looks much more sciency. The SR Box plug-in for OpenSesame allows you to use the SR Box or compatible device in your OpenSesame experiments. The plug-in appears as an item in the item toolbar and you can simply drag it into your experiment.
Screenshot
Setting the device name
By default, the plug-in tries to autodetect your SR Box. If this works, you don’t have to change it. If your experiment freezes, OpenSesame has chosen the wrong serial port and you must enter the device name manually. Under Windows, the device is probably called something like
COM4
Under Linux the device is probably called something like
/dev/tty0
Requirements
An SR Box or compatible device and OpenSesame 0.22 or higher.
Download and installation
As of 0.25, the srbox plugin is included with OpenSesame by default, so no installation is required.
Using the SR Box from Python inline code
class libsrbox
If you insert the srbox plugin at the start of your experiment, an
instance of libsrbox automatically becomes part of the experiment
object and can be accessed from within an inline_script item as
exp.srbox.
Important note 1:
If you do not specify a device, the plug-in will try to autodetect the SR Box port. However, on some systems this freezes the experiment, so it is better to explicitly specify a device.
Important note 2:
You need to call libsrbox.start to put the SR Box in sending mode, before calling libsrbox.get_button_press to collect a button press.
Function list:
- function libsrbox.__init__(experiment, dev=None)
- function libsrbox.close()
- function libsrbox.get_button_press(allowed_buttons=None, timeout=None)
- function libsrbox.send(ch)
- function libsrbox.start()
- function libsrbox.stop()
Example:
t0 = self.time()
exp.srbox.start()
buttonlist, t1 = exp.srbox.get_button_press(allowed_buttons=[1,2])
if 1 in buttonlist:
response_time = t1 - t0
print('Button 1 was pressed in %d ms!' % response_time)
exp.srbox.stop()
function libsrbox.__init__(experiment, dev=None)
Constructor. An srbox object is created automatically by the srbox plug-in, and you do not generally need to call the constructor yourself.
Arguments:
experiment– An Opensesame experiment.- Type: experiment
Keywords:
dev– No description- Default: None
function libsrbox.close()
Closes the connection to the srbox.
function libsrbox.get_button_press(allowed_buttons=None, timeout=None)
Collect a button press from the SR box. This function will return right away if a button is already pressed.
Keywords:
allowed_buttons– A list of buttons that are accepted orNoneto accept all buttons. Valid buttons are integers 1 through 8.- Type: list, NoneType
- Default: None
timeout– A timeout value in milliseconds orNonefor no timeout.- Type: int, float, NoneType
- Default: None
Returns:
A timestamp, buttonlist tuple. The buttonlist consists of a list of button numbers.
- Type: tuple
function libsrbox.send(ch)
Sends a single character to the SR Box.
Arguments:
ch– The character to send.- Type: str
function libsrbox.start()
Turns on sending mode, so that the SR Box starts to send output. The SR Box must be in sending mode when you call libsrbox.get_button_press.
function libsrbox.stop()
Turns off sending mode, so that the SR Box stops giving output.
