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• Create Date May 29, 2017
• Last Updated January 31, 2020

Play Sound File in Real-Time

The purpose of this task is to demonstrate how to produce sounds in real-time using analog outputs as part of KINARM Lab.

For an alternatively method that does NOT play sounds in real-time, but instead works through the Dexterit-E computer, please see the other sample task entitled Tone player – non real-time

This task produces sounds by sending a pre-defined waveform over one analog channel output. If that output is connected to a speaker, then the user will hear the sound.

In order to make sounds in real-time, the following are required:

• one or more analog outputs connected to the Robot computer (e.g. via a PCI card such as NI-6229 connected to a BNC-2090A panel)
  • You will need one analog channel for each independent speaker
• speakers with built-in amplifiers (e.g. headphones, or computer speakers)
• method to connect the analog output(s) to the speaker(s)
  • e.g. if connecting two channels of a BNC-2090A panel to speakers that have a single 3.5 mm stereo jack, the following would work:
    • 2 BNC to RCA/phono jacks - e.g. Newark (54M7978) or Digikey (367-1013-ND)
    • An adapter with 2 RCA/phone plugs to a single 3.5 mm stereo jack - e.g. from Radioshack or the Source
• vector containing the waveform(s) of the desired sound (e.g. download one from the internet, record one yourself, etc)
• MATLAB R2015a is recommended, but not necessary: because Task Programs are run at 4 kHz for R2015a and later, vs 2 kHz for R2013a and prior, using R2015a doubles the frequency range of sounds that are reproduceable

How to use this task:

1. process the desired sound using the attached processWaveformForKINARM.m
   • please read the comments in the code for how to do use this script
   • a sample waveform of a piano keyboard is included
2. connect your speaker(s) to the analog output(s) and turn the speakers on
   • the sample code in this example uses a single analog output (DAC0OUT) of a PCI-6229 card
   • Note: if you have a different analog output card, you will need to modify the task to use the Simulink block corresponding to your card
3. build the task and run it
   • during the build process, the sound waveform becomes embedded in the sample code. So if a different waveform is required, the Task Program will have to be re-built.

This task was built using R2015a SP1, and was compiled for Dexterit-E 3.6.2