Starting definitions: SIDES, LIGHTS, DISPLAYS, and AUDIO
Starting definitions are the very first lines of any protocol file. These definitions handle how you, the user, will identify sides later in the protocol, and how BITTSy will map those side names to devices that are plugged into your computer.
Starting definitions can look like this:
Or, if your protocol does not utilize all the component types that BITTSy can use, you may only need a subset of these definitions:
SIDES
The SIDES definition lists the names that will be used to identify sides in the protocol. In the example above, they are CENTER, LEFT, and RIGHT - but they could be named however you like. They can be listed in any order, but the number of them should correspond to how many distinct sides you will need to refer to later in the protocol.
Once you have decided on your side names and listed them in SIDES, you will use the same ones in the other starting definitions and in action statements throughout your protocol.
The SIDES opening definition is required for any protocol using any type of stimulus presentation: all stimulus types (lights, audio, image/video) require specifying which sides they should be presented on.
DISPLAYS and LIGHTS
Once available side names are given in SIDES, the next thing to set up is how BITTSy will map these names to particular components controlled by your computer, in order to control stimulus presentation across those devices.
Only include definitions for the components (displays/lights) that will be used in that particular protocol. BITTSy will require that all of the defined components are connected and turned on before running the protocol - so if your protocol doesn't use lights, or only uses one central display and not your two side displays, leave out everything that's not used, so that experimenters running the study don't have to power on all the unnecessary components.
The order of the side designations in DISPLAYS and LIGHTS definitions corresponds to their ID numbers (0, 1, 2, etc.) assigned by your computer (which is according to where they are plugged in). Refer to the setup section for details on how to run the setup protocol, which will guide you through the process of identifying your components' ID numbers and setting up your DISPLAYS and LIGHTS definitions to appropriately label what side they are on.
AUDIO
By default, BITTSy assumes the system is set up for stereo audio (2.1), and allows for control of two channels (LEFT and RIGHT) that can be played from individually or simultaneously (with the command CENTER or STEREO). If your computer is equipped with two or one speakers, this is the correct setting for you, and you will not need to include an AUDIO definition.
If your computer has more than two audio channels, you can include an AUDIO definition to say how you will identify each speaker. For example:
Like lights and displays, the order in which the sides are listed in the AUDIO definition should match the order in which the peripheral components (speakers, in this case) are numbered by the computer. That is, the speaker with the lowest ID number is given the first listed side name, the second ID gets the second name, etc. Unlike for the lights and displays, the ordering of audio channel IDs is standardized and predictable. Surround sound-capable sound cards have a standard color-coding system to denote which jacks are for which channel(s), and will be listed in order in your manual. Generally, for a 5.1 system, it will match the example above, and for a 7.1 system, the additional middle channels will have the highest IDs and be defined at the end.
Channel names in the example above match where speakers are typically intended to be placed in a 5.1 surround sound system. But since BITTSy is not applying any audio effects, all the speaker channels are functionally the same. You can physically place them anywhere you like, and choose side names to use in your starting definitions that describe where they are actually located, rather than what the audio jack is labelled to be.
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