├── README.md
└── esp32-i2s-sd.ino


/README.md:
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 1 | # ADMP441 MEMS I2S sample for ESP32
 2 | 
 3 | ## Breakout Board
 4 | 
 5 | Purchased from [OSHPark](https://oshpark.com/shared_projects/ypqAU3CH) via https://github.com/SamEA/ADMP441_Microphone.git
 6 | 
 7 | ### BOM
 8 | ![OSHPark](https://raw.githubusercontent.com/SamEA/ADMP441_Microphone/master/ADMP441%20Breakout%20Board%20Top.png)
 9 | 
10 | 1. R1 - 100kOhm
11 | 2. C1 - 100nF
12 | 3. U1 - ADMP441 MEMS desoldered from Amazon Dash
13 | 
14 | ## ESP32
15 | 
16 | |ADMP441|ESP32|
17 | |-------|-----|
18 | |WS     |IO25 |
19 | |SD     |IO22 |
20 | |SCK    |IO26 |
21 | |VCC    |3.3V |
22 | |GND    |GND  |
23 | 
24 | Wire SD card to VSPI and CS=21
25 | 
26 | ## Usage
27 | 
28 | Dumps I2S PCM data to track.i2s on SD card.
29 | 
30 | Run,
31 | 
32 | ```
33 | ffmpeg -f s32le -ar 16000 -ac 1 -i track.i2s track.wav
34 | ```
35 | 
36 | to convert to a WAV file.  QED.
37 | 


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/esp32-i2s-sd.ino:
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 1 | #include <SD.h>
 2 | #include <driver/gpio.h>
 3 | #include <driver/i2s.h>
 4 | 
 5 | static const int SD_CS = 21;
 6 | static const int bytesToRead = 1024 * 1000;
 7 | File f;
 8 | 
 9 | void setup()
10 | {
11 | 	Serial.begin(115200);
12 | 
13 | 	i2s_config_t i2s_config;
14 | 	i2s_config.mode = (i2s_mode_t) (I2S_MODE_MASTER | I2S_MODE_RX);
15 | 	i2s_config.sample_rate = 16000;
16 | 	i2s_config.bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT;
17 | 	i2s_config.channel_format = I2S_CHANNEL_FMT_ONLY_RIGHT;
18 | 	i2s_config.communication_format = (i2s_comm_format_t) (I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB);
19 | 	i2s_config.dma_buf_count = 32;
20 | 	i2s_config.dma_buf_len = 32 * 2;
21 | 	i2s_config.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1;
22 | 
23 | 	i2s_pin_config_t pin_config;
24 | 	pin_config.bck_io_num = 26;
25 | 	pin_config.ws_io_num = 25;
26 | 	pin_config.data_out_num = I2S_PIN_NO_CHANGE;
27 | 	pin_config.data_in_num = 22;
28 | 
29 | 	i2s_driver_install(I2S_NUM_1, &i2s_config, 0, NULL);
30 | 	i2s_set_pin(I2S_NUM_1, &pin_config);
31 | 	i2s_stop(I2S_NUM_1);
32 | 
33 | 	i2s_start(I2S_NUM_1);
34 | 
35 | 	SD.begin(SD_CS);
36 | 	f = SD.open("/track.i2s", FILE_WRITE);
37 | }
38 | 
39 | void loop()
40 | {
41 | 	static int totalBytesRead = 0;
42 | 	if (totalBytesRead >= bytesToRead) {
43 | 		return;
44 | 	}
45 | 	uint8_t buf[64];
46 | 	memset(buf, 0, 64);
47 | 	int bytes_read = 0;
48 | 	while(bytes_read == 0) {
49 | 		bytes_read = i2s_read_bytes(I2S_NUM_1, (char*) buf, 64, 0);
50 | 	}
51 | 	f.write(buf, 64);
52 | 	totalBytesRead += 64;
53 | 	if (totalBytesRead >= bytesToRead) {
54 | 		f.close();
55 | 		Serial.println("DONE WRITING");
56 | 		return;
57 | 	}
58 | }
59 | 


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