====== Acquiring Digital Codes ======
It is critical that we acquire stimulus-locked digital codes so that we can bin the data according to stimulus type during analysis. This is also essential for creating event-related averages of psychophysiological data (e.g. creating ERPs from EEG data) as it gives us the precise onset time of each stimulus. Below is a description of the hardware, software, and steps necessary for sending and acquiring such codes with PsychoPy and the BioSemi ActiveTwo system.

===== Hardware =====
  * [[http://labjack.com/u3|LabJack U3 DAQ device]]
    * The stimulus presentation computer interfaces with this device via USB. The device then outputs the 8-bit digital signal which is relayed to the MP150 via a 37-pin ribbon cable which connects to a parallel port on the ActiveTwo USB receiver.
  * [[http://www.winfordeng.com/products/brksd37.php|Winford DB37 'Slim' Female Connector Breakout Board]]
    * This breakout board (aka terminal board or terminal block) gives us an easy way of wiring the output from the LabJack U3 to the ribbon cable. 
  * [[http://www.biosemi.com/receiver.htm|ActiveTwo USB receiver I/O]]

<WRAP center round box 80%>
{{ :kpnl:activetwo:labjack.png?0x350 |}}
  - USB from stimulus presentation computer
  - 8-bit digital output from I/O lines FIO0-FIO7.
    - A separate wire connects each line to the breakout board.
  - Wires are connected to screw terminals on the breakout board. Each terminal is connected to a single pin of the female DB-37 connector.
    - FIO0-FIO7 should be wired to terminals 1-8 of the breakout board.
    - The ground should be wired to terminals 9-16 and terminal 37 of the breakout board.
  - A 37-pin ribbon cable connects the breakout board to the ActiveTwo USB receiver.
</WRAP>

===== Software =====

See [[:kpnl:psychopy#Sending digital event codes|here]] for information regarding sending event codes from PsychoPy.