{"id":6146,"date":"2024-03-15T21:55:58","date_gmt":"2024-03-15T20:55:58","guid":{"rendered":"https:\/\/www.pschatzmann.ch\/home\/?p=6146"},"modified":"2024-03-15T22:52:51","modified_gmt":"2024-03-15T21:52:51","slug":"mozzi-revisited","status":"publish","type":"post","link":"https:\/\/www.pschatzmann.ch\/home\/2024\/03\/15\/mozzi-revisited\/","title":{"rendered":"Mozzi Revisited"},"content":{"rendered":"

Mozzi<\/a> brings your Arduino to life by allowing it to produce much more complex and interesting growls, sweeps and chorusing atmospherics. These sounds can be quickly and easily constructed from familiar synthesis units like oscillators, delays, filters and envelopes.<\/p>\n

Mozzi supports quite a lot of different Micro controllers, but it does not have any output method that would let you capture the audio to a stream of data<\/strong>, so I have added some simple integration layer for Mozzi to my AudioTools<\/a>: This lets you send the generated audio via the network or bluetooth, save it to a file or whatever you can imagine…<\/p>\n

Example Sketch<\/h2>\n

Here is the sketch, inspired by Mozzi\/examples\/#01.Basics<\/a> converted to use the AudioTools integration:<\/p>\n

#include \"AudioTools.h\"\n#include \"AudioLibs\/AudioBoardStream.h\"\n#include \"AudioLibs\/MozziStream.h\"\n#include <Oscil.h>                \/\/ oscillator template\n#include <tables\/sin2048_int8.h>  \/\/ sine table for oscillator\n\nconst int sample_rate = 16000;\nAudioInfo info(sample_rate, 1, 16);\nAudioBoardStream i2s(AudioKitEs8388V1);  \/\/ audio sink\nMozziStream mozzi; \/\/ audio source\nStreamCopy copier(i2s, mozzi); \/\/ copy source to sink\n\/\/ use: Oscil <table_size, update_rate> oscilName (wavetable), look in .h file\n\/\/ of table #included above\nOscil<SIN2048_NUM_CELLS, sample_rate> aSin(SIN2048_DATA);\n\/\/ control variable, use the smallest data size you can for anything used in\n\/\/ audio\nbyte gain = 255;\n\nvoid setup() {\n  Serial.begin(115200);\n  AudioLogger::instance().begin(Serial, AudioLogger::Info);\n\n  \/\/ setup mozzi\n  auto cfg = mozzi.defaultConfig();\n  cfg.control_rate = CONTROL_RATE;\n  cfg.copyFrom(info);\n  mozzi.begin(cfg);\n\n  \/\/ setup output\n  auto out_cfg = i2s.defaultConfig();\n  out_cfg.copyFrom(info);\n  i2s.begin(out_cfg);\n\n  \/\/ setup mozzi sine\n  aSin.setFreq(3320);  \/\/ set the frequency\n}\n\nvoid loop() { copier.copy(); }\n\nvoid updateControl() {\n  \/\/ as byte, this will automatically roll around to 255 when it passes 0\n  gain = gain - 3;\n}\n\nint updateAudio() {\n  return (aSin.next() * gain) >>\n         8;  \/\/ shift back to STANDARD audio range, like \/256 but faster\n} \n\n<\/code><\/pre>\n
We just copy the audio from the MozziStream<\/a> source to the AudioBoardStream<\/a> audio sink which is the I2S output for an Audiokit.<\/p>\n
Compared with the original sketch<\/strong>, startMozzi() has been replaced with the mozzi.begin(cfg); and instead of calling audioHook() in the loop we use copier.copy();<\/p>\n
This and further examples can be found in the examples directory and on Github<\/a><\/p>\n
Summary<\/h2>\n
With Mozzi I am supporting now quite a rich set of Audio DSP Libraries<\/p>\n