In my Arduino Audio Tools library I am providing a common API to do FFT against different implementations. I was already testing some of the implementations. On ARM microcontrollers we can use the CMSIS DSP library which usually comes automatically with the Arduino Core. This is not the case for the Arduino UNO R4, but we can install the Arduino CMSIS DSP library with the Arduino library manager. Here is the adapted test sketch that Read more
Today I got very upset by a discussion where a user replaced the original question with a misleading conclusion that mixing an A2DP sink with a sine signal was not possible! Unfortunately he also ignored some helpful comments by some other users. So in order to avoid any confusion I had to delete the whole discussion! Mixing the output from an A2DP sink with a sine signal can be done not only very easily but Read more
I was wondering how to use the timers in the new Arduino UNO R4. Unfortunately I did not find any documentation, so I decided to document my findings here. The UNO R4 has two timer peripherals: the General PWM Timer (GPT) and the Asynchronous General Purpose Timer (AGT). There are only 2 16 bit AGT timers (but one is already used to provide the Arduino millis() and microseconds() methods) and there are 7 GPT timers Read more
In Arduino we can use the analogWrite(pin, value) method to create a PWM signal on the digital pins. The value parameter is used to change the duty cycle but the PWM frequency which is fixed at usually 490 Hz and can not be changed. Here is a simple example sketch that also works with the UNO R4: void setup() { pinMode(D2, OUTPUT); // set 100% analogWrite(D2,255) } void loop() {} Fortunately the Arduino UNO R4 Read more
The easiest way to “record” audio with an Arduino UNO R4 is by using an analog microphone which can be connected to any analog pin. For my test I was using a MCP6022 Microphone Sensor. Arduino Sketch There are no surprises here because we can use the AnalogAudioStream as audio source: #include “AudioTools.h” AnalogAudioStream in; AudioInfo info(8000, 1, 16); CsvOutput<int16_t> out(Serial); // ASCII output stream StreamCopy copier(out, in); // copy i2sStream to CsvOutput // Arduino Read more
This week I received a brand new Arduino UNO R4 in my mail.It uses a Renesas 32 bit microprocessor and has 256 kB Flash and 32 kB RAM. It provides 1 DAC and 6 PWM pins. I got the version which also provides WIFI and a LED matrix. Unfortunately there is no I2S support, but nevertheless I was wondering if I could get some audio from it. I extended my AudioTools Library by implementing a Read more
I thought it should be quite easy to use the new debugging functionality of Arduino 2.0 with the RP2040 using the official RP2040 debug probe in Earle Phil Hower’s core. I am using Arduino on my old Macbook running Linux: And Boy was I wrong! The first challenge was to figure out the correct wiring: The UART from the Debug Probe optinally goes to the UART and a GND pin of the RP2040. Here the Read more
At the very beginning of my Arduino AudioTools project, I was providing a codec for WAV files. It was just handling PCM audio, so it just needed to read or write the header and then could just copy the audio data. In my last blog, I was writing that the ADPCM codec is perfectly suited for encoding and decoding audio on microcontrollers. So the next natural step is to provide a proper ADPCM support for Read more
My AudioTools project is supporting quite a few audio encoders and decoders. They are critical to reduce the storage or transmission volume of audio. Though I support the encoding of AAC and MP3, I can’t really recommend this: it requires a lot of memory and processing time. For an introduction how to use the codecs, please read the Wiki. Below you can find my short list of my favorite codecs which are fast and efficient. Read more
In my last post I was writing about audio containers. But containers are usually also used to mux audio and video together in one file. This made me think, if we could play movies on an ESP32? In fact there are some projects out there that exactly do this: They used Motion-Jpeg to play the movie and store the audio in a separate file, so they actually avoided the complexity of containers. A mjpeg is Read more