Microcontroller FFT & IFFT Performance Benchmark (N=64)

The Fast Fourier Transform (FFT) is an efficient algorithm for computing the Discrete Fourier Transform (DFT): it converts a signal from the time domain into the frequency domain, revealing which frequencies are present in a signal and how strong they are. It is the workhorse behind spectrum analyzers, audio effects, filtering, and countless other DSP applications. I recently published a new FFT library that supports both integer and floating-point data types for its calculations. Using Read more

By pschatzmann, ago

USB Audio Class 2 for STM32 Arduino

In my last blog, I described my USB Audio Class 2 implementation. I was wondering if this functionality can also be used for STM32 micocontrollers. Since the solution relies on the Adafruit_TinyUSB_Arduino library, I was running into the issue that there is only a preliminary support for STM32-F4 micocontrollers. I decided to exend the support for the STM32-F7 and  STM32-H7. You just need to install corresponding stm32 branch from my fork e.g  with cd ~/Documents/Arduino/libraries Read more

By pschatzmann, ago

USB Audio Class 2.0 for Arduino

I’m happy to announce that the Arduino Audio Tools library now includes native USB Audio Class 2.0 (UAC2) support. Your ESP32-S3 or RP2040 board can show up as a standard USB microphone, speaker, or both — no drivers needed on the host side. Linux, macOS, and Windows 10+ recognize it out of the box. Why USB Audio? Most Arduino audio projects use I2S to talk to an external DAC or ADC. That works well, but Read more

By pschatzmann, ago

MP3 Encoding for Microcontrollers (using Shine)

Quite some time ago, I published a blog about using LibLAME as a library to encode PCM audio data to mp3 using a micro-controller. Yesterday I was asking ChatGPT about this topic and it recommended the Shine MP3 encoder. So I took up the task to provide an Arduino compatible Shine Library and integrate it into my AudioTools. Here is a related Arduino test sketch that measures the encoding perfrmance for 44100 stereo audio data Read more

By pschatzmann, ago

TinyGPU for Arduino

I recently needed to add SLAM visualization to QGroundControl. The plan: render a map using a simple graphics library, then encode the output via H.265. That’s how I stumbled into writing TinyGPU—and it quickly became my new favorite tool for lightweight embedded graphics. TinyGPU is a lightweight, header-only C++ library for Arduino that handles RGB565 graphics, sprites, and even basic 3D wireframes on small screens. What Makes TinyGPU Different? Most Arduino graphics libraries try to Read more

By pschatzmann, ago

Bringing H.264 Video to the ESP32-S3 with Arduino

Working with the ESP32-S3 has always been about pushing boundaries—especially when it comes to multimedia. While audio on microcontrollers has become fairly common, video is still considered “out of reach” for most embedded setups. That’s what makes the lightweight H.264 support from Espressif Systems so interesting. Native H.264 Support on ESP32-S3 Espressif provides a compact H.264 encoder and decoder component as part of their ecosystem. This is a big deal: H.264 (also known as AVC) Read more

By pschatzmann, ago

ESP32 Arduino: Setting the Stack Size

I am getting old and usually forget the commands that I rarely use. My solution for this: Just ask AI ! Lately I was running into the issue that my ESP32 Arduino test sketches were crashing because there was not enough stack, but this time ChatGPT completely failed me. I finally found the correct answer in the examples provided by Espressif and it is smiple. Just add the following line to your sketch: // Increase Read more

By pschatzmann, ago

IEEE 802.15.4: Audio and Other Uses

IEEE 802.15.4 is a technical standard defining the Physical and Media Access Control layers for Low-Rate Wireless Personal Area Networks. It enables low-power, low-data-rate wireless connectivity for IoT, smart home, and industrial sensors, allowing devices to operate on batteries for years. Here in Europe it uses the Primary Sub-GHz Band: 868.0–868.6 MHz. It is used e.g. by the smart home protocols Thread/Matter and Zigbee. These smart home protocols are suited to control audio, but they are Read more

By pschatzmann, ago

AudioTools: Adding Support for the ESP32‐S3 AI Smart Speaker Development Board

Recently I found the ESP32‐S3 AI Smart Speaker Development Board on Aliexpress for around 15 USD. It has quite some interesting functionality: ES8311 Codec DAC Chip ES7210 Codec ADC Chip with stereo microphones SD Card 6 Neopixel Multicolor LEDs A PCF85063A Real Time Clock 3 User Definable Keys GPIO interface camera interface lcd interface This week I got this board in my mailbox and I expected it to be quite easy to be added to Read more

By pschatzmann, ago

Implementing a DLNA Control Point in Arduino

In my last blogs, I was showing how to create DLNA devices. In my final blog about this topic I will demonstrate how to create a DLNA Control Point (=Client) which uses the functionality of these devices. I will demo a simple Control Point for a Media Renderer which will start playing some music: The Arduino Sketch First we define the relevant objects: In the Arduino setup() we start the processing: We just start the Read more

By pschatzmann, ago