1. Sound Processing with Pure Data
6.S063 Engineering Interaction Technologies
Prof. Stefanie Mueller | HCI Engineering Group

2. exercise: detect peak in amplitude (mic input)
trigger music to play (or whatever!)

3. here is what you need to know…

4. PureData: visual programming language
download :

5. dataflow:
from top to bottom

6. dataflow:
from top to bottom
INPUTS
OUTPUTS

7. data types: objects messages (numbers, lists, ...)
numbers (float, double, int)
symbols
comments

8. data flow :
needs a trigger (bang)
bang!

9. left-most rule:
change in left inlet triggers the function

10. control flow: comparisons == > >= < <= control flow
trigger

11. benefit: no compile time (programming at runtime)
awesome for prototyping!
quick debugging…

12. reading and writing
audio

13. analog digital converter
digital analog converter
read
audio input
write
audio output

14. read & write
and do something in between ;)

15. what is the ~ sign?
data vs. signal

16. <30s brainstorming>
what does this do?
<30s brainstorming>

17. volume * 2

18. filtering audio signals
(frequency)

19. <30s brainstorming>
which filters are these?
<30s brainstorming>

20. high pass filter > 5hz

21. low pass filter < 1khz

22. band pass filter
only passes 500hz

23. coding time

25. read audio input from channel 1

26. read audio input from channel 1
get average volume over
last 1024 samples

27. read audio input from channel 1
get average volume over
last 1024 samples
compare volume to threshold

28. read audio input from channel 1
get average volume over
last 1024 samples
compare volume to threshold
trigger function if high volume detected

29. pd syntax : right click on object and “help”
ctrl+b opens up the browser
pd-list and/or forum
...google

30. end.