{"id":6400,"date":"2024-10-25T10:17:52","date_gmt":"2024-10-25T08:17:52","guid":{"rendered":"https:\/\/www.pschatzmann.ch\/home\/?p=6400"},"modified":"2024-10-21T19:21:41","modified_gmt":"2024-10-21T17:21:41","slug":"tinyusb-audio-testing-the-microphone-quality","status":"publish","type":"post","link":"https:\/\/www.pschatzmann.ch\/home\/2024\/10\/25\/tinyusb-audio-testing-the-microphone-quality\/","title":{"rendered":"TinyUSB Audio: Testing the Microphone Quality using a Stream"},"content":{"rendered":"

In my last blogs<\/a>, I described how I managed to extend TinyUSB to provide an simple USB Audio device<\/strong> in Arduino.<\/p>\n

So far I have been using some randon numbers<\/strong> to generate noise. This is not very helpful to check if we lost some samples. A SawTooth wave<\/strong> is much more convinient.<\/p>\n

We can use the AudioTools<\/a> to generate this. Here is the example sketch, that also shows how we can define an Arduino Stream as input (as an alternative to the callbacks) that we have used so far.<\/p>\n

#include \"Adafruit_TinyUSB.h\"\n#include \"AudioTools.h\"  \/\/ https:\/\/github.com\/pschatzmann\/arduino-audio-tools\n\nAdafruit_USBD_Audio usb;\nAudioInfo info(44100, 2, 16);\nSawToothGenerator<int16_t> sawtooth;               \nGeneratedSoundStream<int16_t> sawthooth_stream(sawtooth);\n\nvoid setup() {\n  Serial.begin(115200);\n  \/\/while(!Serial);  \/\/ wait for serial\n\n  \/\/ generate 493 hz (note B4)\n  sawtooth.begin(info, 493.0f);\n\n  \/\/ Start USB device as Audio Source\n  usb.setInput(sawthooth_stream);\n  usb.begin(info.sample_rate, info.channels, info.bits_per_sample);\n}\n\nvoid loop() {\n  \/\/ optional: use LED do display status\n  usb.updateLED();\n}\n<\/code><\/pre>\n
We just define a SawTooth, convert it to a GeneratedSoundStream and start the sawtooth by calling begin.<\/p>\n
And here is the result, visualized with the help of Audacity:<\/p>\n
\"\"<\/p>\n
Dependencies<\/h3>\n