GrahamM · March 18, 2025 15:45 · Jun 28, 2020 · Jun 28, 2020 · Jun 27, 2020
diff --git a/receive.py b/receive.py
@@ -1,33 +0,0 @@
-import sys
-import socket
-import wave
-
-UDP_IP = "0.0.0.0"
-UDP_PORT = 3333
-
-if len(sys.argv)>1:
-    srate = int(sys.argv[1])
-else:
-    print("Defaulting to 48KHz sample rate")
-    srate=48000
-
-WAVE_OUTPUT_FILENAME = "output_"+str(srate)+".wav"
-
-sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-sock.bind((UDP_IP, UDP_PORT))
-
-frames = b''
-
-try:
-    while True:
-        data, addr = sock.recvfrom(1024) 
-        frames = frames+data
-
-except KeyboardInterrupt:  
-    print("Writing for rate ",srate)
-    wf = wave.open(WAVE_OUTPUT_FILENAME, 'wb')
-    wf.setnchannels(1)
-    wf.setsampwidth(4)
-    wf.setframerate(srate)
-    wf.writeframes(frames)
-    wf.close()

diff --git a/receive.py b/receive.py
@@ -0,0 +1,33 @@
+import sys
+import socket
+import wave
+
+UDP_IP = "0.0.0.0"
+UDP_PORT = 3333
+
+if len(sys.argv)>1:
+    srate = int(sys.argv[1])
+else:
+    print("Defaulting to 48KHz sample rate")
+    srate=48000
+
+WAVE_OUTPUT_FILENAME = "output_"+str(srate)+".wav"
+
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+sock.bind((UDP_IP, UDP_PORT))
+
+frames = b''
+
+try:
+    while True:
+        data, addr = sock.recvfrom(1024) 
+        frames = frames+data
+
+except KeyboardInterrupt:  
+    print("Writing for rate ",srate)
+    wf = wave.open(WAVE_OUTPUT_FILENAME, 'wb')
+    wf.setnchannels(1)
+    wf.setsampwidth(4)
+    wf.setframerate(srate)
+    wf.writeframes(frames)
+    wf.close()
diff --git a/I2S_MIC_UDP.ino b/I2S_MIC_UDP.ino
@@ -0,0 +1,143 @@
+/**
+ * ESP32 I2S UDP Streamer
+ *
+ * This is influenced by maspetsberger's NoiseLevel at 
+ * https://github.com/maspetsberger/esp32-i2s-mems/blob/master/examples/NoiseLevel/NoiseLevel.ino
+ *
+ * @author GrahamM
+ */
+
+#include <driver/i2s.h>
+#include <soc/i2s_reg.h>
+#include "WiFi.h"
+#include "AsyncUDP.h"
+
+
+// WiFi network name and password:
+const char* ssidName = "<WiFiName>";
+const char* ssidPswd = "<WiFiPassword>";
+
+// UDP Destination
+IPAddress udpAddress(192, 168, 250, 119);
+const int udpPort = 3333;
+// Connection state
+boolean connected = false;
+
+//The udp library class
+AsyncUDP udp;
+
+const i2s_port_t I2S_PORT = I2S_NUM_0;
+const int BLOCK_SIZE = 128;
+
+void setup() {
+    Serial.begin(115200);
+    Serial.println(" * Configuring WiFi");
+    setupWiFi();
+    Serial.println(" * Configuring I2S");
+    I2SSetup();
+
+}
+
+void setupWiFi() {
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(ssidName, ssidPswd);
+    if (WiFi.waitForConnectResult() != WL_CONNECTED) {
+        Serial.println("WiFi Failed");
+        while (1) {
+            delay(1000);
+        }
+    }
+}
+
+void I2SSetup() {
+    esp_err_t err;
+
+    // The I2S config as per the example
+    const i2s_config_t i2s_config = {
+        .mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_RX), // We drive clk but only receive
+                               // 112000 and below seem to be cleaner
+        .sample_rate = 112000, //16000, 32000, 44100, 48000, 96000, 112000, 128000, 144000, 160000, 176000, 192000
+        .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT, // WS signal must be BCLK/64 - this is how we manage it
+        .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,  // Left by default
+        .communication_format = i2s_comm_format_t(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
+        .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,     // Interrupt level 1
+        .dma_buf_count = 4,                           // number of buffers
+        .dma_buf_len = BLOCK_SIZE,                    // samples per buffer
+    };
+
+    // The pin config as per the setup
+    const i2s_pin_config_t pin_config = {
+        .bck_io_num = 14,   // Bit Clk
+        .ws_io_num = 12,    // LR Clk
+        .data_out_num = -1, // Data out
+        .data_in_num = 32   // Data in
+    };
+
+    // Configuring the I2S driver and pins.
+    err = i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);
+    if (err != ESP_OK) {
+        Serial.printf(" ! Failed installing driver: %d\n", err);
+        while (true);
+    }
+
+    // Alterations for SPH0645 to ensure we receive MSB correctly.
+    REG_SET_BIT(I2S_TIMING_REG(I2S_PORT), BIT(9));   // I2S_RX_SD_IN_DELAY
+    REG_SET_BIT(I2S_CONF_REG(I2S_PORT), I2S_RX_MSB_SHIFT);  // Phillips I2S - WS changes a cycle earlier
+
+    err = i2s_set_pin(I2S_PORT, &pin_config);
+    if (err != ESP_OK) {
+        Serial.printf(" ! Failed setting pin: %d\n", err);
+        while (true);
+    }
+    Serial.println(" + I2S driver installed.");
+}
+
+int32_t buffer[512];    // Effectively two 1024 byte buffers
+volatile uint16_t rPtr = 0; // Yes, I should be using a pointer.
+
+void mic_record()
+{
+    int num_bytes_read = i2s_read_bytes(I2S_PORT,
+        (char*)buffer + rPtr,
+        BLOCK_SIZE,     // Number of bytes
+        portMAX_DELAY); // No timeout
+
+    rPtr = rPtr + num_bytes_read;
+    // Wrap this when we get to the end of the buffer
+    if (rPtr > 2043) rPtr = 0;
+}
+
+
+void loop() {
+    static uint8_t state = 0;
+    mic_record();
+
+    if (!connected) {
+        if (udp.connect(udpAddress, udpPort)) {
+            connected = true;
+            Serial.println(" * Connected to host");
+        }
+    }
+    else {
+        switch (state) {
+            case 0: // wait for index to pass halfway
+                if (rPtr > 1023) {
+                    state = 1;
+                }
+                break;
+            case 1: // send the first half of the buffer
+                state = 2;
+                udp.write( (uint8_t *)buffer, 1024);
+                break;
+            case 2: // wait for index to wrap
+                if (rPtr < 1023) {
+                    state = 3;
+                }
+                break;
+            case 3: // send second half of the buffer
+                state = 0;
+                udp.write((uint8_t*)buffer+1024, 1024);
+                break;
+        }
+    }   
+}