1.6 KiB
Stream I2S Input to A2DP Bluetooth
General Description:
We implement a A2DP source: We stream the sound input which we read in from the I2S interface to a A2DP sink. We can use any device which provides the sound data via I2S. In order to test the functionality we use the INMP441 microphone. Because the Microphone only provides data on one channel, we the ConverterFillLeftAndRight class to copy the data to the other channel as well.
In this Sketch we are using Streams!
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.
Pins
| INMP441 | ESP32 |
|---|---|
| VDD | 3.3 |
| GND | GND |
| SD | IN (GPIO32) |
| L/R | GND |
| WS | WS (GPIO15) |
| SCK | BCK (GPIO14) |
- SCK: Serial data clock for I²S interface
- WS: Select serial data words for the I²S interface
- L/R: Left / right channel selection When set to low, the microphone emits signals on the left channel of the I²S frame. When the high level is set, the microphone will send signals on the right channel.
- ExSD: Serial data output of the I²S interface
- VCC: input power 1.8V to 3.3V
- GND: Power groundHigh PSR: -75 dBFS.