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Shutter controller
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Shutter control is provided for paradigms which require precisely timed visual stimulation. The electronically operated shutter is attached to the lens of  any type of slide projector using velcro which allows it to be removed if required. The controller allows shutter open and shutter close as separate functions under control of the experiment control file. It also provides connections which may be hooked up to the slide advance and reverse functions of the slide projector, allowing complete automation. The controller illustrated is a dual device, typically used in a backward masking paradigm where one image is shown briefly immediately followed by a different, longer image. The shutter controller is subject to re-design and improvement, September 1998.

An example of use of shutter controller is given in the Classic conditioning experiment.

 

The controller is capable of activating the open and close shutter mechanism in about 3mS, using energy accumulated in reservoir capacitors. At present, it is set up to operate with the same command provided in PSYLAB measurement system to operate the RL8 Relay device. The relay command has two parameters, the first is a number between 0 and 255 which controls the state of 8 relays using binary weight (e.g. 1=relay 1, 2=relay 2, 4= relay 3, etc.). The second parameter is the length of time the selected relay/s remain closed.

With the shutter controller, two of these relays are replaced with the shutter open and close circuits. The circuit needs only brief activation to discharge its energy into the shutter solenoid, 0.2 seconds is more than enough, and it is undesirable to activate it for long time periods. The command to open the shutter is Relay 16,.2 and the command to close it is Relay 32,.2

The shutter controller (single version) includes two relays like the RL8 relay coupler. These should be wired up so that they close across the buttons used to advance and reverse the slide carousel, which requires the button to be 'held on' for about 1 second to move a single slide. These respond to commands Relay 1,1 (advance) and Relay 2,1 (reverse).

This only employs four of the possible 8 individual functions available with the Relay command. The unused functions (Relay 4,1 Relay 8,1) are used if the shutter controller is a dual device, allowing control of a second slide carousel; Relay 64,.2 and Relay 128,.2 would be used to open and close the second shutter.

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