initial commit

mic/mic.ino~

@@ -0,0 +1,183 @@
+#include <WiFi.h>
+#include <WiFiUdp.h>
+#include <math.h>
+#include <driver/i2s.h>
+#include <driver/touch_pad.h>
+
+const char* ssid = "Fios-8EKF5";
+const char* password = "hero816cars7050jon";
+const char* DEST_IP = "192.168.1.190";
+const int UDP_PORT = 5004;
+
+const int OUTPUT_RATE = 8000; // 8kHz rtp payload rate
+const int MIC_RATE = 16000;   // capture rate inmp441
+const int FRAME_SIZE  = 160;  // 20ms frames @ 8kHz
+const float TONE_HZ   = 440.0;
+
+const touch_pad_t TOUCH_PIN = TOUCH_PAD_NUM4; // gpio13
+const int TOUCH_THRESHOLD = 800; // adjust as needed
+
+// inmp441 pins - change as needed
+const int I2S_WS  = 22; // lrcl / ws
+const int I2S_SCK = 26; // bclk
+const int I2S_SD  = 21; // data from mic to esp32
+
+WiFiUDP udp;
+uint16_t seq = 0;
+uint32_t ts = 0;
+bool tone_mode = true; // start with tone
+
+struct rtp_hdr {
+  uint8_t vpxcc;
+  uint8_t mpt;
+  uint16_t seq;
+  uint32_t ts;
+  uint32_t ssrc;
+};
+
+static const int16_t exp_lut[256] = {
+  0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
+  5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+};
+
+uint8_t linear2ulaw(int16_t pcm_val) {
+  int sign = (pcm_val >> 8) & 0x80;
+  if (sign) pcm_val = (short)-pcm_val;
+  if (pcm_val > 32635) pcm_val = 32635;
+  pcm_val = pcm_val + 0x84;
+  int exponent = exp_lut[(pcm_val >> 7) & 0xFF];
+  int mantissa = (pcm_val >> (exponent + 3)) & 0x0F;
+  return ~(sign | (exponent << 4) | mantissa);
+}
+
+void setup() {
+  Serial.begin(115200);
+  
+  // init touch
+  touch_pad_init();
+  touch_pad_set_voltage(TOUCH_HVOLT_2V7, TOUCH_LVOLT_0V5, TOUCH_HVOLT_ATTEN_1V);
+  touch_pad_config(TOUCH_PIN, 0);
+  
+  // init i2s for adc sampling
+  i2s_config_t i2s_config = {
+    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_ADC_BUILT_IN),
+    .sample_rate = OUTPUT_RATE,
+    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
+    .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
+    .communication_format = I2S_COMM_FORMAT_STAND_MSB,
+    .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
+    .dma_buf_count = 8,
+    .dma_buf_len = 128,
+    .use_apll = false
+  };
+  
+  i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
+  i2s_set_adc_mode(ADC_UNIT_1, ADC1_CHANNEL_0); // gpio36
+  i2s_adc_enable(I2S_NUM_0);
+  
+  WiFi.begin(ssid, password);
+  while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); }
+  Serial.printf("\nconnected, ip=%s\n", WiFi.localIP().toString().c_str());
+  udp.begin(UDP_PORT);
+  
+  Serial.println("tap pin 13 to switch modes");
+}
+
+void loop() {
+  static unsigned long last_send = 0;
+  static unsigned long last_touch_check = 0;
+  static bool last_touch_state = false;
+  static const unsigned long FRAME_INTERVAL = 20; // 20ms
+  static const unsigned long TOUCH_CHECK_INTERVAL = 50; // check every 50ms
+  
+  // check touch state periodically
+  unsigned long now = millis();
+  if (now - last_touch_check > TOUCH_CHECK_INTERVAL) {
+    uint16_t touch_val;
+    touch_pad_read(TOUCH_PIN, &touch_val);
+    bool touched = touch_val < TOUCH_THRESHOLD;
+    
+    // detect touch press (not hold)
+    if (touched && !last_touch_state) {
+      tone_mode = !tone_mode;
+      Serial.printf("switched to %s mode\n", tone_mode ? "tone" : "mic");
+      delay(200); // debounce
+    }
+    
+    last_touch_state = touched;
+    last_touch_check = now;
+  }
+  
+  // only send if it's time
+  if (now - last_send < FRAME_INTERVAL) {
+    yield();
+    return;
+  }
+  
+  uint8_t packet[12 + FRAME_SIZE];
+  int16_t samples[FRAME_SIZE];
+  
+  if (tone_mode) {
+    // fixed tone generation with integer phase accumulator
+    static uint32_t phase_acc = 0;
+    const uint32_t phase_inc_int = (uint32_t)(TONE_HZ * (1ULL << 32) / OUTPUT_RATE);
+    
+    for (int i = 0; i < FRAME_SIZE; i++) {
+      float phase = (phase_acc >> 16) * (2.0 * M_PI / 65536.0);
+      samples[i] = (int16_t)(16000.0 * sinf(phase));
+      phase_acc += phase_inc_int;
+    }
+    
+  } else {
+    // read from i2s adc buffer - need multiple reads to fill frame
+    static float dc_filter = 2048.0; // dc offset removal filter
+    int samples_filled = 0;
+    
+    while (samples_filled < FRAME_SIZE) {
+      size_t bytes_read;
+      uint16_t i2s_buffer[64]; // bigger buffer
+      i2s_read(I2S_NUM_0, i2s_buffer, 128, &bytes_read, 10);
+      
+      int samples_read = bytes_read / 2; // 2 bytes per sample
+      for (int i = 0; i < samples_read && samples_filled < FRAME_SIZE; i++) {
+        // i2s adc gives 12-bit data in upper bits of 16-bit word
+        int adc_val = (i2s_buffer[i] >> 4) & 0x0FFF;
+        
+        // dc offset removal with simple iir filter
+        dc_filter = dc_filter * 0.999 + adc_val * 0.001;
+        
+        // scale and store
+        samples[samples_filled] = (int16_t)((adc_val - dc_filter) * 16);
+        samples_filled++;
+      }
+    }
+  }
+  
+  // µ-law encode
+  for (int i = 0; i < FRAME_SIZE; i++) {
+    packet[12 + i] = linear2ulaw(samples[i]);
+  }
+  
+  // build rtp header
+  rtp_hdr* hdr = (rtp_hdr*)packet;
+  hdr->vpxcc = 0x80;
+  hdr->mpt   = 0x00;
+  hdr->seq   = htons(seq++);
+  hdr->ts    = htonl(ts);
+  hdr->ssrc  = htonl(0x12345678);
+  
+  // send packet
+  udp.beginPacket(DEST_IP, UDP_PORT);
+  udp.write(packet, sizeof(packet));
+  
+  ts += FRAME_SIZE;
+  last_send = now;
+  
+  yield();
+}