48 lines
2.2 KiB
Markdown
48 lines
2.2 KiB
Markdown
## Micro Speech
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The staring point for doing speech recognition on an Arduino based board is TensorFlow Light For Microcontrollers with the example sketch called micro_speech!
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I have adapted the MicroSpeech example from TensorFlow Lite to follow the philosophy of this framework. The example uses a Tensorflow model which can recognise the words 'yes' and 'no'. The output stream class is TfLiteAudioOutput. In the example I am using an ESP32 AudioKit board, but you can replace this with any type of processor with a microphone.
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Further information can be found in the [Wiki](https://github.com/pschatzmann/arduino-audio-tools/wiki/TensorFlow-Lite---MicroSpeech).
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To capture the Audio we use an INMP441 Microphone:
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The INMP441 is a high-performance, low power, digital-output, omnidirectional MEMS microphone with a bottom port. The complete INMP441 solution consists of a MEMS sensor, signal conditioning, an analog-to-digital converter, anti-aliasing filters, power management, and an industry-standard 24-bit I²S interface. The I²S interface allows the INMP441 to connect directly to digital processors, such as DSPs and microcontrollers, without the need for an audio codec in the system.
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## Pins
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| INMP441 | ESP32
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| --------| ---------------
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| VDD | 3.3
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| GND | GND
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| SD | IN (GPIO32)
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| L/R | GND
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| WS | WS (GPIO15)
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| SCK | BCK (GPIO14)
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- SCK: Serial data clock for I²S interface
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- WS: Select serial data words for the I²S interface
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- L/R: Left / right channel selection
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When set to low, the microphone emits signals on the left channel of the I²S frame.
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When the high level is set, the microphone will send signals on the right channel.
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- ExSD: Serial data output of the I²S interface
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- VCC: input power 1.8V to 3.3V
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- GND: Power groundHigh PSR: -75 dBFS.
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### Note
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The log level has been set to Info to help you to identify any problems. Please change it to AudioLogger::Warning to get the best sound quality!
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## Dependencies
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You need to install the following libraries:
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- https://github.com/pschatzmann/arduino-audio-tools
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- https://github.com/pschatzmann/tflite-micro-arduino-examples
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