Wi-Fi Music-Reactive Robot

#include <Arduino.h>
#include <WiFi.h>
#include <WebServer.h>
#include <SPI.h>
#include <SD.h>
#include <ESP32Servo.h>
#include <Adafruit_NeoPixel.h>
#include <driver/i2s.h>

// HypeBeat standalone local-control firmware.
// CLOUD_HOOK marks the non-blocking locations for a future cloud database client.
const char *AP_SSID = "HypeBeat-Control";
const char *AP_PASSWORD = "hypebeat123"; // Change before demonstrating publicly.
constexpr uint8_t MIC_PIN=34, I2S_BCLK_PIN=26, I2S_LRCK_PIN=25, I2S_DOUT_PIN=27;
constexpr uint8_t PAN_SERVO_PIN=32, TILT_SERVO_PIN=33, LED_DATA_PIN=21, STATUS_LED_PIN=13;
constexpr uint8_t SD_CS_PIN=4, SD_SCK_PIN=18, SD_MISO_PIN=19, SD_MOSI_PIN=23, PIXELS=8;

WebServer server(80); SPIClass sdSPI(VSPI); Servo panServo, tiltServo;
Adafruit_NeoPixel strip(PIXELS, LED_DATA_PIN, NEO_GRB+NEO_KHZ800);
File wav; File uploadFile; bool sdReady=false, playing=false, session=true, lights=true;
uint8_t bright=128, rr=120, gg=0, bb=255; String mode="groove", current=""; unsigned long lastMove=0;

uint16_t le16(const uint8_t *p){return p[0]|(p[1]<<8);} uint32_t le32(const uint8_t *p){return p[0]|(p[1]<<8)|(p[2]<<16)|(p[3]<<24);}
String safeName(String n){int p=n.lastIndexOf('/');if(p>=0)n=n.substring(p+1);String s;for(size_t i=0;i<n.length();i++){char c=n[i];if(isAlphaNumeric(c)||c=='.'||c=='_'||c=='-')s+=c;}return s.length()?s:"music.wav";}
void showLights(){strip.setBrightness(bright);uint32_t c=lights?strip.Color(rr,gg,bb):0;for(int i=0;i<PIXELS;i++)strip.setPixelColor(i,c);strip.show();}
void stopAudio(){if(wav)wav.close();playing=false;}
bool beginWav(String requested){stopAudio();String p=requested.startsWith("/")?requested:"/"+requested;if(!sdReady||!SD.exists(p))return false;wav=SD.open(p);uint8_t h[44];if(wav.read(h,44)!=44||memcmp(h,"RIFF",4)||memcmp(h+8,"WAVE",4)||memcmp(h+12,"fmt ",4)||memcmp(h+36,"data",4)){wav.close();return false;}uint16_t format=le16(h+20),channels=le16(h+22),bits=le16(h+34);uint32_t rate=le32(h+24);if(format!=1||channels>2||bits!=16||rate<8000||rate>48000){wav.close();return false;}i2s_set_clk(I2S_NUM_0,rate,I2S_BITS_PER_SAMPLE_16BIT,channels==2?I2S_CHANNEL_STEREO:I2S_CHANNEL_MONO);current=p;playing=true;return true;}
void feedAudio(){if(!playing)return;static uint8_t input[512];int n=wav.read(input,sizeof(input));if(n<=0){stopAudio();return;}size_t done=0;i2s_write(I2S_NUM_0,input,n,&done,0);}
String listFiles(){String out="[";bool first=true;if(sdReady){File root=SD.open("/");File f=root.openNextFile();while(f){String n=f.name(),low=n;low.toLowerCase();if(!f.isDirectory()&&low.endsWith(".wav")){if(!first)out+=',';out+='\"'+n+'\"';first=false;}f.close();f=root.openNextFile();}root.close();}return out+"]";}
void sendState(){String out="{\"sdReady\":"+String(sdReady?"true":"false")+",\"playing\":"+String(playing?"true":"false")+",\"ip\":\""+WiFi.softAPIP().toString()+"\",\"file\":\""+current+"\"}";server.send(200,"application/json",out);}
void changeControl(){if(server.hasArg("lights"))lights=server.arg("lights")=="1";if(server.hasArg("session"))session=server.arg("session")=="1";if(server.hasArg("brightness"))bright=constrain(server.arg("brightness").toInt(),0,255);if(server.hasArg("r"))rr=constrain(server.arg("r").toInt(),0,255);if(server.hasArg("g"))gg=constrain(server.arg("g").toInt(),0,255);if(server.hasArg("b"))bb=constrain(server.arg("b").toInt(),0,255);if(server.hasArg("mode"))mode=server.arg("mode");showLights();/* CLOUD_HOOK: publish current controls */sendState();}
void receiveUpload(){HTTPUpload &u=server.upload();if(!sdReady)return;if(u.status==UPLOAD_FILE_START){String p="/"+safeName(u.filename);if(SD.exists(p))SD.remove(p);uploadFile=SD.open(p,FILE_WRITE);}else if(u.status==UPLOAD_FILE_WRITE&&uploadFile)uploadFile.write(u.buf,u.currentSize);else if((u.status==UPLOAD_FILE_END||u.status==UPLOAD_FILE_ABORTED)&&uploadFile)uploadFile.close();}
void moveHead(){if(!session||mode=="idle"){panServo.write(90);tiltServo.write(90);return;}if(millis()-lastMove<50)return;lastMove=millis();int lo=4095,hi=0;for(int i=0;i<24;i++){int x=analogRead(MIC_PIN);lo=min(lo,x);hi=max(hi,x);}int maxAngle=mode=="party"?48:26;int a=constrain(map(hi-lo,10,900,2,maxAngle),2,maxAngle);panServo.write(constrain(90+random(-a,a+1),35,145));tiltServo.write(constrain(90+a/2,55,125));}
void root(){const char page[] PROGMEM=R"HTML(<!doctype html><html><meta name="viewport" content="width=device-width,initial-scale=1"><style>body{font-family:Arial;background:#181020;color:#fff;margin:20px}section{border:1px solid #8040a0;margin:10px 0;padding:10px;border-radius:8px}button,input,select{font-size:16px;margin:3px;padding:7px}button{background:#8040df;color:#fff;border:0;border-radius:5px}</style><h1>HypeBeat local control</h1><p id="s">Loading</p><section><b>Music — 16-bit PCM WAV only in this build</b><form action="/upload" method="post" enctype="multipart/form-data"><input type="file" name="music" accept="audio/wav"><button>Upload WAV</button></form><select id="f"></select><button onclick="post('/play?file='+encodeURIComponent(f.value))">Play</button><button onclick="post('/stop')">Stop</button></section><section><b>Lights</b><input id="c" type="color" value="#7800ff"><input id="br" type="range" min="0" max="255" value="128"><label><input id="on" type="checkbox" checked>On</label><button onclick="light()">Apply</button></section><section><b>Movement</b><select id="m"><option value="idle">Idle</option><option value="groove" selected>Groove</option><option value="party">Party</option></select><label><input id="se" type="checkbox" checked>React to sound</label><button onclick="post('/control?session='+(se.checked?1:0)+'&mode='+m.value)">Apply</button></section><script>async function post(x){await fetch(x,{method:'POST'});refresh()}async function refresh(){let x=await(await fetch('/state')).json();s.textContent='Open http://'+x.ip+' | SD '+(x.sdReady?'ready':'missing')+(x.playing?' | playing '+x.file:'');let a=await(await fetch('/files')).json();f.innerHTML=a.map(x=>'<option>'+x+'</option>').join('')}function light(){let x=c.value;post('/control?lights='+(on.checked?1:0)+'&brightness='+br.value+'&r='+parseInt(x.slice(1,3),16)+'&g='+parseInt(x.slice(3,5),16)+'&b='+parseInt(x.slice(5,7),16))}refresh();setInterval(refresh,3000)</script></html>)HTML";server.send(200,"text/html",page);}
void setup(){Serial.begin(115200);pinMode(STATUS_LED_PIN,OUTPUT);strip.begin();showLights();panServo.setPeriodHertz(50);tiltServo.setPeriodHertz(50);panServo.attach(PAN_SERVO_PIN,500,2400);tiltServo.attach(TILT_SERVO_PIN,500,2400);sdSPI.begin(SD_SCK_PIN,SD_MISO_PIN,SD_MOSI_PIN,SD_CS_PIN);sdReady=SD.begin(SD_CS_PIN,sdSPI,10000000);i2s_config_t c={.mode=(i2s_mode_t)(I2S_MODE_MASTER|I2S_MODE_TX),.sample_rate=44100,.bits_per_sample=I2S_BITS_PER_SAMPLE_16BIT,.channel_format=I2S_CHANNEL_FMT_RIGHT_LEFT,.communication_format=I2S_COMM_FORMAT_STAND_MSB,.intr_alloc_flags=0,.dma_buf_count=8,.dma_buf_len=256,.use_apll=false,.tx_desc_auto_clear=true,.fixed_mclk=0};i2s_pin_config_t p={.bck_io_num=I2S_BCLK_PIN,.ws_io_num=I2S_LRCK_PIN,.data_out_num=I2S_DOUT_PIN,.data_in_num=I2S_PIN_NO_CHANGE};i2s_driver_install(I2S_NUM_0,&c,0,nullptr);i2s_set_pin(I2S_NUM_0,&p);WiFi.mode(WIFI_AP);WiFi.softAP(AP_SSID,AP_PASSWORD);digitalWrite(STATUS_LED_PIN,HIGH);server.on("/",HTTP_GET,root);server.on("/state",HTTP_GET,sendState);server.on("/files",HTTP_GET,[](){server.send(200,"application/json",listFiles());});server.on("/control",HTTP_POST,changeControl);server.on("/play",HTTP_POST,[](){if(!server.hasArg("file")||!beginWav(safeName(server.arg("file"))))server.send(400,"text/plain","Use a 16-bit PCM WAV file");else sendState();});server.on("/stop",HTTP_POST,[](){stopAudio();sendState();});server.on("/upload",HTTP_POST,[](){if(uploadFile)uploadFile.close();server.send(200,"text/plain","Upload complete");},receiveUpload);server.begin();}
void loop(){server.handleClient();feedAudio();moveHead();/* CLOUD_HOOK: database polling or subscription */}