TF-Lite micro_speech – An ESP32 Audio Provider using Arduino Audio Tools

In one of my latest Blogs I described how the API for an easy to use the micro_speech should look like. However I was struggling to make it work. So I decided to do some baby steps and make the existing example work first with my audio-tools library. We need to implement the (missing) methods defined audio_provider.h: InitAudioRecording GetAudioSamples LatestAudioTimestamp InitAudioRecording Init is easy: we just need to start i2s: TfLiteStatus InitAudioRecording(tflite::ErrorReporter* error_reporter) { AudioLogger::instance().begin(Serial, Read more

By pschatzmann, ago

Unstable Zerotier Connections…My WordPress is down!

The last two days this WordPress site was down several times. I restarted my local server and things started to work but when I checked a couple of hours later the connection was down again. I am using Zerotier to connect the public server to my local machine and indeed a ping revealed that the connection was down. Pings to other servers were working, but the machine with WordPress was not reachable. So I started Read more

By pschatzmann, ago

An Introduction to Speech Recognition with Arduino

The staring point for doing speech recognition on an Arduino based board is TensorFlow Light For Microcontrollers with the example sketch called micro_speech! There are quite a few alternative Arduino Libraries for TensorFlow Light but honestly the situation is rather dire and I could not find any version which would fit my requirements support multiple microcontrollers (ESP32, RP2040 and Arduino Based MBED Implementations (e.g. Nano BLE Sense)) w/o compile errors no further dependencies It took Read more

By pschatzmann, ago

TTS with Pre-Recorded Audio: Removing Silence

In my introductory blog, I have described that it would be cool to remove the silence from the recorded samples. If we look at one of the recordings we can see that they start and end with some silence: I have created a SilenceRemovalConverter which does exactly this. The first parameters indicates the number of samples we consider (if the last n samples were silence we remove the sample), the second the threshold value. Here Read more

By pschatzmann, ago

TTS with Pre-Recorded Audio: Preparing the Audio Files

I the last Blog I introduced you to my new Simple TTS Arduino Library which is available on Github. I used the Text-to-Speech (TTS) functionality of Google Translate to generate the mp3 files, which was quite tedious to do manually. Then I executed xxd to generate a .h file from an mp3 recording with: xxd -i mp3file.mp3 header-file.h The header files are then made available with the logic that can be found in AudioDictionary.h Tools Read more

By pschatzmann, ago

TTS with Pre-Recorded Audio: Building a Talking Clock

Last year I was digging into Arduino Based TTS Solutions and came to the conclusion that the available engines will not provide any quality audio and therefore recommended to consider an approach which is based on recorded audio samples. Today I took the opportunity to create the new arduino-simple-tts project which is based on this approach. As a proof of concept I have implemented the speaking of numbers and of the output of time. All Read more

By pschatzmann, ago

Using stdio.h file operations on Arduino ESP32 to access a SD Drive

So far I was always using the Arduino based SD API to access files on a SD drive. But there are plenty of existing libraries which expect to use stdio.h operations to work with files. So I was digging into the topic and to my surprise this is possible: You just need to mount the SD card: #include <FS.h> #include <SD_MMC.h> #include <stdio.h> void begin() { if(!SD_MMC.begin(“/sdcard”)){ Serial.println(“Card Mount Failed”); return; } } The value Read more

By pschatzmann, ago

Maximilian DSP on the Arduino ESP32 ?

Quite some time ago I have identified Maximilian as interesting tool which can be used to implement synthezisers. Maximilian is a cross-platform and multi-target audio synthesis and signal processing library. So I was wondering if it is possible to use it on Arduino based Microcontrollers. In the meantime the adapted library is compiling after some slight changes. After that I started to extend my Arduino Audio Tools to provide an nice integration and a first Read more

By pschatzmann, ago

Building an Arduino ESP32 Audio Bluetooth Receiver with output to SPDIF with just a few lines of code.

The last couple of days I have spent to add SDIF audio output support to my Arduino AudioTools library and I would like to thank joba-1 for testing the solution. Together with my ESP32-A2DP Bluetooth library we can build now a Bluetooth receiver that outputs the audio signals as SPDIF with just a few lines of code: The Arduino Sketch Here is the Arduino Sketch #define USE_A2DP #include “AudioConfigLocal.h” #include “AudioTools.h” BluetoothA2DPSink a2dp_sink; SPDIFStream spdif; Read more

By pschatzmann, ago

AAC Encoding on the AudioKit

For quite some time I was wondering why my arduino-fdk-aac library was using so much memory for the encoding of AAC files. Now that I have an AudioKit working with the debugger it was easier to analyze the situation and – oh boy – I found quite some errors. So I decided to address the issues and published a new corrected release. Arduino Sketch Here is a quick Arduino Sketch which demonstrates how to use Read more

By pschatzmann, ago