Holcombe:Optacon

SUPA Sydney University Perception and Action Lab Primer editing help refcard

USING THE OPTACON

Instructions for using the Optacon setup (draft)

Overview of set-up

• Tower+Monitor uses “Optacon Stimulator” software to provide input to Optacon Interface (the rectangular box with the TRS connectors/jacks).
• The Optacon Interface uses input from Opticon Stimulator to drive the optacon
• Powerlab box reads from Optacon Interface
• Response buttons are connected to the Powerlab box
• Laptop with Labchart collects the output from Powerlab box (button presses and signal from pins)

Switching on the system

• Turn on the computers
• Turn on Powerlab box (switch at back next to grey cord)
• Turn on Optacon Interface (switch on top of box where it says Power)
• Optacon should be the last thing you switch on

Switching off the system

• Optacon should be the first thing you switch off
• Then switch off the Optacon Interface + Powerlab box
• Then switch off computers

Input to Optacon interface

• The tower+monitor provides input to the optacon interface

• Open Optacon Stimulator
• Create New or Open
• Uses .txt files – can make these in excel etc.
• Array (frames) is the input
• Dwell time – how long it stays on that frame
• Pins have fixed vibration rate
  • Single protraction/retraction is 4.35ms for ~230Hz vibration
• Dwell time specifies how long the pins vibrate in the arrangement of that frame
  • Note: Should take into account 4.35ms “frame duration”
    • e.g. if you put 5ms, It will do 2 protractions/frames, actually taking 8.7ms

• OR Click on cells to manually change them

• In array/frames for input: specify number of Blocks and Stimuli
• Blocks are like the Folder
  • Stimuli are within blocks
• Can repeat blocks or stimuli independently

• In the input window for the pins
  • ANIMATE – can visualize how the pins are moving
  • Switch off animate when running experiment
    • Can cause lag if it is switched on
  • LOOP – will repeat whole sequence including blocks, stimuli – toggle on/off

• First 5 seconds of task should be empty –
  • Might be vibrations due to noise etc, so have first 5 seconds empty to ensure experiment starts off clean

• Powerlab box
  • Can choose which pins the Powerlab box records from

"Data Collection"

• Laptop has Labchart on it
  • Uses this for data collection

Starting Labchart:

• Labchart shortcut is on the desktop
• When labchart loads it will seach for optacon interface

**If optacon interface is powered off you can still load labchart ***e.g. if you want to look at data **If you want to use it with the optacon interface make sure interface is on first

• To use settings that have been made for use with optacon:
  • Open a template (e.g ‘example’)
    • Then: File – new – will ask if want to use settings based on other worksheet – click ‘yes’

Testing if everything is connected properly

• Make a file that shows the button presses and the pins you are interested in recording from
• Run and check if button presses and pin recordings correspond to the correct channel
  • e.g. Pin input test – test everything is plugged in properly

Recording:

• Press START button in the bottom right hand corner to start recording
• Top 3 channels shows input – i.e. response from pressing buttons
• Bottom 3 channels records from pins
• Can toggle MONITOR to the left of start button – it will monitor responses/input but doesn’t record
  • Make sure it is off when you want to collect data
    • Monitor Off / Recording– Not showing red X
    • Monitor On / Not Recording – Showing red X

• Can also set up new channels to calculate things from the other channels

Saving:

• Save raw data as an .adicht file before doing anything
• Can select data points – ‘save as’ data file

For stats:

• File – export – labchart txt file

• Samples at 10k a second – can downsample it for smaller file size - this may reduce precision of optacon pins because they are very fast (so find a suitable sampling rate for your purposes)

Notes for running participants

• Instruct participants that they do not need to press hard on buttons
  • Feels like it isn’t registering but it is
• Use scales to measure pressure on fingers
  • Keep this constant over conditions and participants
  • If pressure is too high – will dampen the vibrations – should be gently touching

Misc notes:

• Pull out blue cord at back of optacon to use the visual input part of the optacon
• Switch at back – INVERT – black on white or white on black
• Make sure optacon is not resting on the array – can damage the pins
• ALWAYS BE CAREFUL – it is a fragile piece of equipment we can’t easily replace

--Elizabeth Nguyen 01:47, 13 July 2012 (EDT)