Build An Esp32-c3 Plane Radar Using Super Mini

/*
 * Pico 2W Plane Radar
 * Plots live ADS-B aircraft on a 1.8" ST7735 128×160 SPI TFT display.
 * First-boot softAP portal (192.168.4.1) stores Wi-Fi + location in NVS/LittleFS.
 * Range button on GP15: short press cycles 5→10→15→25 km.
 * Hold range button for 3 s to clear saved credentials and relaunch the portal.
 *
 * Board  : Raspberry Pi Pico 2W (RP2350 + CYW43439)
 * Display: 1.8" / 1.77" 128×160 ST7735 TFT (makershop / generic module)
 * Inspired by MatixYo's ESP32-Plane-Radar: https://github.com/MatixYo/ESP32-Plane-Radar
 */

#include <Arduino.h>
#include <WiFi.h>
#include <WebServer.h>
#include <Preferences.h>
#include <HTTPClient.h>
#include <WiFiClientSecure.h>
#include <ArduinoJson.h>
#include <LovyanGFX.hpp>
#include <math.h>

// ── Pin assignments ──────────────────────────────────────────────────────────
#define RADAR_RST    0    // GP0  — display RES (reset)
#define RADAR_CS     1    // GP1  — SPI0 CSn
#define RADAR_SCLK   2    // GP2  — SPI0 SCK
#define RADAR_MOSI   3    // GP3  — SPI0 TX (MOSI / SDA)
#define RADAR_A0     4    // GP4  — display A0 (data/command, same as DC)
#define RADAR_LED    5    // GP5  — display LED backlight (HIGH = on)
#define RANGE_BUTTON 15   // GP15 — range cycle / credential reset (active LOW)

// ── Display geometry (128 wide × 160 tall, portrait) ────────────────────────
#define DISP_W        128
#define DISP_H        160
// Radar circle centred at (64, 90); radius 58 px leaves room for labels
#define RADAR_CX      64
#define RADAR_CY      90
#define RADAR_RADIUS  56

// ── Radar settings ───────────────────────────────────────────────────────────
#define FETCH_INTERVAL_MS 5000
#define HOLD_CLEAR_MS     3000
#define AP_SSID           "PlaneRadar-Setup"
#define NVS_NAMESPACE     "planeradar"

// ── LovyanGFX display class (ST7735, SPI0) ───────────────────────────────────
class RadarDisplay : public lgfx::LGFX_Device {
  lgfx::Bus_SPI       _bus;
  lgfx::Panel_ST7735  _panel;
public:
  RadarDisplay() {
    auto busCfg        = _bus.config();
    busCfg.spi_host    = 0;           // SPI0
    busCfg.freq_write  = 27000000;    // 27 MHz — safe for most ST7735 modules
    busCfg.pin_sclk    = RADAR_SCLK;
    busCfg.pin_mosi    = RADAR_MOSI;
    busCfg.pin_miso    = -1;
    busCfg.pin_dc      = RADAR_A0;
    _bus.config(busCfg);
    _panel.setBus(&_bus);

    auto panelCfg      = _panel.config();
    panelCfg.pin_cs    = RADAR_CS;
    panelCfg.pin_rst   = RADAR_RST;
    panelCfg.panel_width  = 128;
    panelCfg.panel_height = 160;
    panelCfg.memory_width  = 132;     // ST7735 has 132-column RAM
    panelCfg.memory_height = 162;     // and 162-row RAM
    panelCfg.offset_x = 2;           // common for black-tab modules
    panelCfg.offset_y = 1;
    panelCfg.invert   = false;
    panelCfg.rgb_order = false;
    _panel.config(panelCfg);
    setPanel(&_panel);
  }
};

// ── Math helpers ─────────────────────────────────────────────────────────────

// Forward declarations
double haversineKm(double lat1, double lon1, double lat2, double lon2);
double initialBearing(double lat1, double lon1, double lat2, double lon2);

static const double DEG2RAD = M_PI / 180.0;

double haversineKm(double lat1, double lon1, double lat2, double lon2) {
  double dlat = (lat2 - lat1) * DEG2RAD;
  double dlon = (lon2 - lon1) * DEG2RAD;
  double a = sin(dlat / 2) * sin(dlat / 2)
           + cos(lat1 * DEG2RAD) * cos(lat2 * DEG2RAD)
           * sin(dlon / 2) * sin(dlon / 2);
  return 6371.0 * 2.0 * atan2(sqrt(a), sqrt(1.0 - a));
}

double initialBearing(double lat1, double lon1, double lat2, double lon2) {
  double dlon = (lon2 - lon1) * DEG2RAD;
  double y = sin(dlon) * cos(lat2 * DEG2RAD);
  double x = cos(lat1 * DEG2RAD) * sin(lat2 * DEG2RAD)
           - sin(lat1 * DEG2RAD) * cos(lat2 * DEG2RAD) * cos(dlon);
  double bearing = atan2(y, x) / DEG2RAD;
  return fmod(bearing + 360.0, 360.0);
}

// ── Globals ──────────────────────────────────────────────────────────────────
RadarDisplay display;
Preferences  prefs;
WebServer    configServer(80);

float  radarRangeKm = 10.0f;
double radarLat     = 0.0;
double radarLon     = 0.0;
bool   configMode   = false;

unsigned long lastFetchMs  = 0;
unsigned long btnPressedAt = 0;
bool          btnWasLow    = false;

// ── Forward declarations ─────────────────────────────────────────────────────
void drawRadarShell();
void drawAircraft(float bearingDeg, float distanceKm, const char* label);
void fetchAircraft();
void startConfigPortal();
void handleConfigRoot();
void handleConfigSave();
void showMessage(const char* line1, const char* line2 = nullptr);

// ── Display helpers ──────────────────────────────────────────────────────────
void drawRadarShell() {
  display.fillScreen(TFT_BLACK);

  // Three range rings at 1/4, 1/2, 3/4 and full radius
  display.drawCircle(RADAR_CX, RADAR_CY, RADAR_RADIUS,       TFT_GREEN);
  display.drawCircle(RADAR_CX, RADAR_CY, (RADAR_RADIUS*3)/4, TFT_DARKGREEN);
  display.drawCircle(RADAR_CX, RADAR_CY, RADAR_RADIUS/2,     TFT_DARKGREEN);
  display.drawCircle(RADAR_CX, RADAR_CY, RADAR_RADIUS/4,     TFT_DARKGREEN);

  // Cross-hair lines
  display.drawLine(RADAR_CX - RADAR_RADIUS, RADAR_CY,
                   RADAR_CX + RADAR_RADIUS, RADAR_CY, TFT_DARKGREEN);
  display.drawLine(RADAR_CX, RADAR_CY - RADAR_RADIUS,
                   RADAR_CX, RADAR_CY + RADAR_RADIUS, TFT_DARKGREEN);

  // Cardinal labels
  display.setTextColor(TFT_WHITE, TFT_BLACK);
  display.setTextSize(1);
  display.drawString("N", RADAR_CX - 3, RADAR_CY - RADAR_RADIUS - 10);
  display.drawString("S", RADAR_CX - 3, RADAR_CY + RADAR_RADIUS + 2);
  display.drawString("W", RADAR_CX - RADAR_RADIUS - 10, RADAR_CY - 4);
  display.drawString("E", RADAR_CX + RADAR_RADIUS + 2,  RADAR_CY - 4);

  // Title bar
  display.setTextColor(TFT_CYAN, TFT_BLACK);
  display.drawString("PLANE RADAR", 14, 4);

  // Range label bottom-right
  char rangeBuf[10];
  snprintf(rangeBuf, sizeof(rangeBuf), "%dkm", (int)radarRangeKm);
  display.setTextColor(TFT_YELLOW, TFT_BLACK);
  display.drawString(rangeBuf, DISP_W - 30, DISP_H - 12);
}

void drawAircraft(float bearingDeg, float distanceKm, const char* label) {
  if (distanceKm > radarRangeKm) return;
  float angle  = (bearingDeg - 90.0f) * (float)DEG2RAD;
  float radius = (distanceKm / radarRangeKm) * (float)RADAR_RADIUS;
  int   px     = RADAR_CX + (int)(cosf(angle) * radius);
  int   py     = RADAR_CY + (int)(sinf(angle) * radius);
  display.fillTriangle(px, py - 4, px - 3, py + 3, px + 3, py + 3, TFT_RED);
  display.setTextColor(TFT_WHITE, TFT_BLACK);
  display.setTextSize(1);
  display.drawString(label,
                     constrain(px + 5, 0, DISP_W - 20),
                     constrain(py - 8, 0, DISP_H - 10));
}

void showMessage(const char* line1, const char* line2) {
  display.fillScreen(TFT_BLACK);
  display.setTextColor(TFT_WHITE, TFT_BLACK);
  display.setTextSize(1);
  display.setCursor(4, 70);
  display.print(line1);
  if (line2) {
    display.setCursor(4, 85);
    display.print(line2);
  }
}

// ── Config portal ─────────────────────────────────────────────────────────────
static const char CONFIG_HTML[] PROGMEM = R"rawhtml(
<!DOCTYPE html><html><head>
<meta name='viewport' content='width=device-width,initial-scale=1'>
<title>PlaneRadar Setup</title>
<style>body{font-family:sans-serif;max-width:380px;margin:40px auto;padding:0 16px}
input{width:100%;box-sizing:border-box;padding:8px;margin:6px 0 14px;font-size:15px}
button{width:100%;padding:10px;background:#27ae60;color:#fff;border:none;font-size:16px;cursor:pointer}
h2{margin-bottom:4px}p{color:#555;font-size:13px;margin-top:0}</style>
</head><body>
<h2>PlaneRadar Setup</h2>
<p>Enter your Wi-Fi details and the coordinates for the radar centre.</p>
<form method='POST' action='/save'>
<label>Wi-Fi Name (SSID)</label><input name='ssid' required>
<label>Wi-Fi Password</label><input name='pass' type='password'>
<label>Latitude (e.g. 52.3676)</label><input name='lat' required placeholder='52.3676'>
<label>Longitude (e.g. 4.9041)</label><input name='lon' required placeholder='4.9041'>
<button type='submit'>Save &amp; Connect</button>
</form>
</body></html>
)rawhtml";

static const char SAVED_HTML[] PROGMEM = R"rawhtml(
<!DOCTYPE html><html><head>
<meta name='viewport' content='width=device-width,initial-scale=1'>
<title>Saved</title>
<style>body{font-family:sans-serif;max-width:380px;margin:40px auto;padding:0 16px}</style>
</head><body>
<h2>Saved!</h2>
<p>The radar is connecting to your Wi-Fi. You can close this page.</p>
</body></html>
)rawhtml";

void handleConfigRoot() { configServer.send(200, "text/html", CONFIG_HTML); }

void handleConfigSave() {
  String ssid = configServer.arg("ssid");
  String pass = configServer.arg("pass");
  String lat  = configServer.arg("lat");
  String lon  = configServer.arg("lon");

  prefs.begin(NVS_NAMESPACE, false);
  prefs.putString("ssid", ssid);
  prefs.putString("pass", pass);
  prefs.putDouble("lat",  lat.toDouble());
  prefs.putDouble("lon",  lon.toDouble());
  prefs.end();

  configServer.send(200, "text/html", SAVED_HTML);
  delay(1500);
  rp2040.reboot();
}

void startConfigPortal() {
  configMode = true;
  WiFi.mode(WIFI_AP);
  WiFi.softAP(AP_SSID);
  Serial.print("Config portal at: ");
  Serial.println(WiFi.softAPIP());

  configServer.on("/",     HTTP_GET,  handleConfigRoot);
  configServer.on("/save", HTTP_POST, handleConfigSave);
  configServer.begin();

  showMessage("PlaneRadar-Setup", "192.168.4.1");
}

// ── Aircraft fetch ────────────────────────────────────────────────────────────
void fetchAircraft() {
  if (WiFi.status() != WL_CONNECTED) return;

  float nm = radarRangeKm / 1.852f;
  WiFiClientSecure client;
  client.setInsecure();  // public read-only data; no CA bundle on Pico
  String url = "https://opendata.adsb.fi/api/v3/lat/"
             + String(radarLat, 5)
             + "/lon/"
             + String(radarLon, 5)
             + "/dist/"
             + String(nm, 1);

  HTTPClient http;
  http.begin(client, url);
  http.setTimeout(4000);
  int code = http.GET();

  if (code == HTTP_CODE_OK) {
    JsonDocument doc;
    DeserializationError err = deserializeJson(doc, http.getStream());
    if (err) {
      Serial.printf("JSON error: %s\n", err.c_str());
      http.end();
      return;
    }

    drawRadarShell();
    int plotted = 0;

    for (JsonObject plane : doc["ac"].as<JsonArray>()) {
      if (!plane["lat"].is<double>() || !plane["lon"].is<double>()) continue;

      double acLat   = plane["lat"].as<double>();
      double acLon   = plane["lon"].as<double>();
      double distKm  = haversineKm(radarLat, radarLon, acLat, acLon);
      double bearDeg = initialBearing(radarLat, radarLon, acLat, acLon);

      if (distKm > radarRangeKm) continue;

      const char* label = plane["flight"] | plane["hex"] | "AC";
      drawAircraft((float)bearDeg, (float)distKm, label);
      plotted++;
    }
    Serial.printf("Plotted %d aircraft within %.0f km\n", plotted, radarRangeKm);
  } else {
    Serial.printf("HTTP error: %d\n", code);
  }
  http.end();
}

// ── Setup ─────────────────────────────────────────────────────────────────────
void setup() {
  Serial.begin(115200);
  pinMode(RANGE_BUTTON, INPUT_PULLUP);

  // Backlight on
  pinMode(RADAR_LED, OUTPUT);
  digitalWrite(RADAR_LED, HIGH);

  display.init();
  display.setRotation(0);   // portrait: 128 wide × 160 tall
  display.setTextSize(1);
  drawRadarShell();

  prefs.begin(NVS_NAMESPACE, true);
  String savedSsid = prefs.getString("ssid", "");
  String savedPass = prefs.getString("pass", "");
  radarLat         = prefs.getDouble("lat", 0.0);
  radarLon         = prefs.getDouble("lon", 0.0);
  prefs.end();

  if (savedSsid.length() == 0) {
    Serial.println("No credentials — starting config portal");
    startConfigPortal();
    return;
  }

  showMessage("Connecting to WiFi...", savedSsid.c_str());
  WiFi.mode(WIFI_STA);
  WiFi.begin(savedSsid.c_str(), savedPass.c_str());

  unsigned long t0 = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - t0 < 20000) {
    delay(250);
  }

  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("Wi-Fi failed — starting config portal");
    startConfigPortal();
    return;
  }

  Serial.printf("Connected. IP: %s  Lat: %.4f  Lon: %.4f\n",
                WiFi.localIP().toString().c_str(), radarLat, radarLon);
  drawRadarShell();
}

// ── Loop ──────────────────────────────────────────────────────────────────────
void loop() {
  if (configMode) {
    configServer.handleClient();
    return;
  }

  // Range button: short press cycles range; hold 3 s clears credentials
  bool btnLow = (digitalRead(RANGE_BUTTON) == LOW);

  if (btnLow && !btnWasLow) {
    btnPressedAt = millis();
    btnWasLow = true;
  }

  if (!btnLow && btnWasLow) {
    unsigned long held = millis() - btnPressedAt;
    btnWasLow = false;

    if (held >= HOLD_CLEAR_MS) {
      Serial.println("Long press — clearing credentials");
      prefs.begin(NVS_NAMESPACE, false);
      prefs.clear();
      prefs.end();
      delay(200);
      rp2040.reboot();
    } else {
      if      (radarRangeKm ==  5) radarRangeKm = 10;
      else if (radarRangeKm == 10) radarRangeKm = 15;
      else if (radarRangeKm == 15) radarRangeKm = 25;
      else                         radarRangeKm =  5;
      Serial.printf("Range → %.0f km\n", radarRangeKm);
      drawRadarShell();
    }
  }

  if (millis() - lastFetchMs >= FETCH_INTERVAL_MS) {
    lastFetchMs = millis();
    fetchAircraft();
  }
}