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IFD:EAI SoS21/course material/Session 6: Getting Started with Teensyduino: Difference between revisions
IFD:EAI SoS21/course material/Session 6: Getting Started with Teensyduino (view source)
Revision as of 17:33, 25 May 2021
, 25 May 2021→Homework: Coding an Envelope follower
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==Homework: Coding an Envelope follower== | ==Homework: Coding an Envelope follower== | ||
If you were successful with setting up the teensy and piezo microphone, you can make a step further and learn how to wrestle with audio data directly on the teensy! | If you were successful with setting up the teensy and piezo microphone, you can make a step further and learn how to wrestle with audio data directly on the teensy! | ||
We want to call a so called envelope follower, it tracks the peaks of our audio signal and gets the rough volume shape. With the help of the volume (~loudness) of our signal we can detect wether there is vibration on our piezo or not. In rough terms we get the volume envelope in two steps: | |||
# get the maximum of the signal samples seen so far | |||
# multiply this maximum with a decay factor (<1) for every new sample (or sample block) | |||
With the help of the [https://www.pjrc.com/teensy/td_libs_AudioNewObjects.html teensy documentation] and [[:File:envelope_follower_template.zip|my empty template file]] you should be able to grasp how this works. Basically you write your own teensy audio object by including a C++ class that is structured as documented in the link above. This class will receive a pointer to the audio input stream coming from the piezo and can do some work on it. If you have questions about the template code please ask on our [https://signal.group/#CjQKIGr9R1a7Znwe1Ca0pmbx3rvHHzDaS1c_LnmgwwVk1KoSEhB6aHUiokel3vtGVoTErtfB signal group]! | With the help of the [https://www.pjrc.com/teensy/td_libs_AudioNewObjects.html teensy documentation] and [[:File:envelope_follower_template.zip|my empty template file]] you should be able to grasp how this works. Basically you write your own teensy audio object by including a C++ class that is structured as documented in the link above. This class will receive a pointer to the audio input stream coming from the piezo and can do some work on it. If you have questions about the template code please ask on our [https://signal.group/#CjQKIGr9R1a7Znwe1Ca0pmbx3rvHHzDaS1c_LnmgwwVk1KoSEhB6aHUiokel3vtGVoTErtfB signal group]! | ||