loudness.tc

loudness.tc — microphone loudness / VU meter using the TinyC I2S mic (RX) syscalls.

Source on GitHub

// loudness.tc — microphone loudness / VU meter using the TinyC I2S mic (RX) syscalls.
//
// Uses an OWN I2S RX channel (a separate I2S port), fully independent of the audio
// plugin — so it works on ANY ESP32 with an I2S mic:
//   • raw I2S MEMS mic (INMP441 / ICS-43434 / SPH0645): just wire BCLK / WS / DIN.
//   • codec mic (ES8311 / ES7210, e.g. the P4 board): enable the codec's ADC first
//     via the i2c* syscalls (or let the audio plugin init it), then point DIN at the
//     codec's I2S data line.
//
// Requires firmware ABI >= 7:
//   int  i2sMicBegin(mclk, bclk, lrclk, din, rate)  // 0 = ok, -1 = error (mclk=-1 = none)
//   int  i2sMicLevel()                               // RMS amplitude 0..32767 (loudness)
//   int  i2sMicRead(int arr[], max)                  // raw int16 mono samples (FFT/custom)
//   void i2sMicStop()
//
// This file is for a RAW I2S MEMS mic (INMP441/ICS-43434) — MCLK not needed (-1).
// For the P4 board's ES7210 codec mic, see loudness_p4.tc (needs MCLK + I2C init).
//
// Console:  MIC   -> prints the current level.

// ── set these to YOUR mic wiring ──
#define MIC_MCLK   -1      // -1 = none (raw MEMS mic); a codec needs the MCLK pin
#define MIC_BCLK   15
#define MIC_WS     16
#define MIC_DIN    17
#define MIC_RATE   16000

int micok = 0;
int level = 0;        // current RMS (0..32767)
int peak  = 0;        // meter peak (fast attack, slow decay)

// integer sqrt — gives a more ear-like meter than a linear map (no float needed)
int isqrt(int n) {
    if (n <= 0) { return 0; }
    int x = n;
    int y = (x + 1) / 2;
    while (y < x) { x = y; y = (x + n / x) / 2; }
    return x;
}

// 0..32767 RMS -> 0..100 %, sqrt-shaped (sqrt(32767) = 181)
int pct_of(int rms) {
    int p = (isqrt(rms) * 100) / 181;
    if (p > 100) { p = 100; }
    return p;
}

void Every100ms() {
    if (!micok) { return; }
    int v = i2sMicLevel();              // RMS over one ~256-sample block
    if (v < 0) { return; }              // mic not open
    level = v;
    if (v > peak) { peak = v; }         // fast attack
    else { peak = (peak * 9) / 10; }    // slow decay
}

void Command(char cmd[]) {
    char resp[64];
    sprintf(resp, "rms=%d (%d%%) peak=%d", level, pct_of(level), pct_of(peak));
    responseCmnd(resp);
}

void WebUI() {
    char buf[256];
    int p = pct_of(level);
    int pk = pct_of(peak);
    sprintf(buf, "{s}Loudness{m}%d %% (rms %d){e}", p, level);
    webSend(buf);
    // a little bar with a peak marker
    sprintf(buf, "{s}Level{m}<div style='position:relative;background:#222;width:170px;height:14px;border-radius:7px'><div style='background:#3ddc84;height:14px;width:%d%%;border-radius:7px'></div><div style='position:absolute;top:0;left:%d%%;width:2px;height:14px;background:#e66'></div></div>{e}", p, pk);
    webSend(buf);
}

int main() {
    micok = (i2sMicBegin(MIC_MCLK, MIC_BCLK, MIC_WS, MIC_DIN, MIC_RATE) == 0);
    if (micok) { addLog("loudness: mic RX started"); }
    else { addLog("loudness: i2sMicBegin FAILED — check pins / firmware ABI>=7"); }
    addCommand("MIC");
    return 0;
}