PicoWiFiAnalyzer.ino
/*
 * Pico W WiFi Analyzer
 * Require Raspberry Pi Pico W board support.
 */

#define SCAN_INTERVAL 3000
// #define SCAN_COUNT_SLEEP 3

/*******************************************************************************
 * Start of Arduino_GFX setting
 *
 * Arduino_GFX try to find the settings depends on selected board in Arduino IDE
 * Or you can define the display dev kit not in the board list
 * Defalult pin list for non display dev kit:
 * Arduino Nano, Micro and more: CS:  9, DC:  8, RST:  7, BL:  6, SCK: 13, MOSI: 11, MISO: 12
 * ESP32 various dev board     : CS:  5, DC: 27, RST: 33, BL: 22, SCK: 18, MOSI: 23, MISO: nil
 * ESP32-C3 various dev board  : CS:  7, DC:  2, RST:  1, BL:  3, SCK:  4, MOSI:  6, MISO: nil
 * ESP32-S2 various dev board  : CS: 34, DC: 38, RST: 33, BL: 21, SCK: 36, MOSI: 35, MISO: nil
 * ESP32-S3 various dev board  : CS: 40, DC: 41, RST: 42, BL: 48, SCK: 36, MOSI: 35, MISO: nil
 * ESP8266 various dev board   : CS: 15, DC:  4, RST:  2, BL:  5, SCK: 14, MOSI: 13, MISO: 12
 * Raspberry Pi Pico dev board : CS: 17, DC: 27, RST: 26, BL: 28, SCK: 18, MOSI: 19, MISO: 16
 * RTL8720 BW16 old patch core : CS: 18, DC: 17, RST:  2, BL: 23, SCK: 19, MOSI: 21, MISO: 20
 * RTL8720_BW16 Official core  : CS:  9, DC:  8, RST:  6, BL:  3, SCK: 10, MOSI: 12, MISO: 11
 * RTL8722 dev board           : CS: 18, DC: 17, RST: 22, BL: 23, SCK: 13, MOSI: 11, MISO: 12
 * RTL8722_mini dev board      : CS: 12, DC: 14, RST: 15, BL: 13, SCK: 11, MOSI:  9, MISO: 10
 * Seeeduino XIAO dev board    : CS:  3, DC:  2, RST:  1, BL:  0, SCK:  8, MOSI: 10, MISO:  9
 * Teensy 4.1 dev board        : CS: 39, DC: 41, RST: 40, BL: 22, SCK: 13, MOSI: 11, MISO: 12
 ******************************************************************************/
#include <Arduino_GFX_Library.h>

#define GFX_BL DF_GFX_BL // default backlight pin, you may replace DF_GFX_BL to actual backlight pin

/* More dev device declaration: https://github.com/moononournation/Arduino_GFX/wiki/Dev-Device-Declaration */
#if defined(DISPLAY_DEV_KIT)
Arduino_GFX *gfx = create_default_Arduino_GFX();
#else /* !defined(DISPLAY_DEV_KIT) */

/* More data bus class: https://github.com/moononournation/Arduino_GFX/wiki/Data-Bus-Class */
Arduino_DataBus *bus = create_default_Arduino_DataBus();

/* More display class: https://github.com/moononournation/Arduino_GFX/wiki/Display-Class */
Arduino_GFX *gfx = new Arduino_ILI9341(bus, DF_GFX_RST, 3 /* rotation */, false /* IPS */);

#endif /* !defined(DISPLAY_DEV_KIT) */
/*******************************************************************************
 * End of Arduino_GFX setting
 ******************************************************************************/

#include "WiFi.h"
#define log_i(format, ...) Serial.printf(format, ##__VA_ARGS__)

int16_t w, h, text_size, banner_height, graph_baseline, graph_height, channel_width, signal_width;

// RSSI RANGE
#define RSSI_CEILING -40
#define RSSI_FLOOR -100

// Channel color mapping from channel 1 to 14
uint16_t channel_color[] = {
    RED, ORANGE, YELLOW, GREEN, CYAN, BLUE, MAGENTA,
    RED, ORANGE, YELLOW, GREEN, CYAN, BLUE, MAGENTA};

uint8_t scan_count = 0;

void setup()
{
  Serial.begin(115200);
  // Serial.setDebugOutput(true);
  // while(!Serial);
  Serial.println("Arduino_GFX Pico WiFi Analyzer example");

  // Set WiFi to station mode and disconnect from an AP if it was previously connected
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  delay(100);

#ifdef GFX_EXTRA_PRE_INIT
  GFX_EXTRA_PRE_INIT();
#endif

#ifdef GFX_BL
  pinMode(GFX_BL, OUTPUT);
  digitalWrite(GFX_BL, HIGH);
#endif

  // Init Display
  if (!gfx->begin())
  {
    Serial.println("gfx->begin() failed!");
  }
  w = gfx->width();
  h = gfx->height();
  text_size = (h < 200) ? 1 : 2;
  banner_height = text_size * 3 * 4;
  graph_baseline = h - 20;                            // minus 2 text lines
  graph_height = graph_baseline - banner_height - 30; // minus 3 text lines
  channel_width = w / 17;
  signal_width = channel_width * 2;

  // init banner
  gfx->setTextSize(text_size);
  gfx->fillScreen(BLACK);
  gfx->setTextColor(MAGENTA);
  gfx->setCursor(0, 0);
  gfx->print("Pico W");
  gfx->setTextColor(WHITE);
  gfx->print(" WiFi Analyzer");
}

bool matchBssidPrefix(uint8_t *a, uint8_t *b)
{
  for (uint8_t i = 0; i < 5; i++)
  { // only compare first 5 bytes
    if (a[i] != b[i])
    {
      return false;
    }
  }
  return true;
}

void loop()
{
  uint8_t ap_count_list[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
  int32_t noise_list[] = {RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR};
  int32_t peak_list[] = {RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR, RSSI_FLOOR};
  int16_t peak_id_list[] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1};
  int32_t channel;
  int16_t idx;
  int32_t rssi;
  uint8_t bssidA[6];
  uint8_t bssidB[6];
  String ssid;
  uint16_t color;
  int16_t height, offset, text_width;

  // WiFi.scanNetworks will return the number of networks found
  int n = WiFi.scanNetworks();

  // clear old graph
  gfx->fillRect(0, banner_height, w, h - banner_height, BLACK);
  gfx->setTextSize(1);

  if (n == 0)
  {
    gfx->setTextColor(WHITE);
    gfx->setCursor(0, banner_height);
    gfx->println("no networks found");
  }
  else
  {
    for (int i = 0; i < n; i++)
    {
      channel = WiFi.channel(i);
      idx = channel - 1;
      rssi = WiFi.RSSI(i);
      WiFi.BSSID(i, bssidA);

      // channel peak stat
      if (peak_list[idx] < rssi)
      {
        peak_list[idx] = rssi;
        peak_id_list[idx] = i;
      }

      // check signal come from same AP
      bool duplicate_SSID = false;
      for (int j = 0; j < i; j++)
      {
        if ((WiFi.channel(j) == channel) && matchBssidPrefix(WiFi.BSSID(j, bssidB), bssidA))
        {
          duplicate_SSID = true;
          break;
        }
      }

      if (!duplicate_SSID)
      {
        ap_count_list[idx]++;

        // noise stat
        int32_t noise = rssi - RSSI_FLOOR;
        noise *= noise;
        if (channel > 4)
        {
          noise_list[idx - 4] += noise;
        }
        if (channel > 3)
        {
          noise_list[idx - 3] += noise;
        }
        if (channel > 2)
        {
          noise_list[idx - 2] += noise;
        }
        if (channel > 1)
        {
          noise_list[idx - 1] += noise;
        }
        noise_list[idx] += noise;
        if (channel < 14)
        {
          noise_list[idx + 1] += noise;
        }
        if (channel < 13)
        {
          noise_list[idx + 2] += noise;
        }
        if (channel < 12)
        {
          noise_list[idx + 3] += noise;
        }
        if (channel < 11)
        {
          noise_list[idx + 4] += noise;
        }
      }
    }

    // plot found WiFi info
    for (int i = 0; i < n; i++)
    {
      channel = WiFi.channel(i);
      idx = channel - 1;
      rssi = WiFi.RSSI(i);
      color = channel_color[idx];
      height = constrain(map(rssi, RSSI_FLOOR, RSSI_CEILING, 1, graph_height), 1, graph_height);
      offset = (channel + 1) * channel_width;

      // trim rssi with RSSI_FLOOR
      if (rssi < RSSI_FLOOR)
      {
        rssi = RSSI_FLOOR;
      }

      // plot chart
      // gfx->drawLine(offset, graph_baseline - height, offset - signal_width, graph_baseline + 1, color);
      // gfx->drawLine(offset, graph_baseline - height, offset + signal_width, graph_baseline + 1, color);
      gfx->startWrite();
      gfx->writeEllipseHelper(offset, graph_baseline + 1, signal_width, height, 0b0011, color);
      gfx->endWrite();

      if (i == peak_id_list[idx])
      {
        // Print SSID, signal strengh and if not encrypted
        String ssid = WiFi.SSID(i);
        if (ssid.length() == 0)
        {
          WiFi.BSSID(i, bssidA);
          // bssidA to ssid
          char mac[18] = {0};
          sprintf(mac, "%02X:%02X:%02X:%02X:%02X:%02X", bssidA[0], bssidA[1], bssidA[2], bssidA[3], bssidA[4], bssidA[5]);
          ssid = String(mac);
        }
        text_width = (ssid.length() + 6) * 6;
        if (text_width > w)
        {
          offset = 0;
        }
        else
        {
          offset -= signal_width;
          if ((offset + text_width) > w)
          {
            offset = w - text_width;
          }
        }
        gfx->setTextColor(color);
        gfx->setCursor(offset, graph_baseline - 10 - height);
        gfx->print(ssid);
        gfx->print('(');
        gfx->print(rssi);
        gfx->print(')');
        if (WiFi.encryptionType(i) == ENC_TYPE_NONE)
        {
          gfx->print('*');
        }
      }
    }
  }

  // print WiFi stat
  gfx->setTextColor(WHITE);
  gfx->setCursor(0, banner_height);
  gfx->print(n);
  gfx->print(" networks found, lesser noise channels: ");
  bool listed_first_channel = false;
  int32_t min_noise = noise_list[0];          // init with channel 1 value
  for (channel = 2; channel <= 11; channel++) // channels 12-14 may not available
  {
    idx = channel - 1;
    log_i("min_noise: %d, noise_list[%d]: %d", min_noise, idx, noise_list[idx]);
    if (noise_list[idx] < min_noise)
    {
      min_noise = noise_list[idx];
    }
  }

  for (channel = 1; channel <= 11; channel++) // channels 12-14 may not available
  {
    idx = channel - 1;
    // check channel with min noise
    if (noise_list[idx] == min_noise)
    {
      if (!listed_first_channel)
      {
        listed_first_channel = true;
      }
      else
      {
        gfx->print(", ");
      }
      gfx->print(channel);
    }
  }

  // draw graph base axle
  gfx->drawFastHLine(0, graph_baseline, 320, WHITE);
  for (channel = 1; channel <= 14; channel++)
  {
    idx = channel - 1;
    offset = (channel + 1) * channel_width;
    gfx->setTextColor(channel_color[idx]);
    gfx->setCursor(offset - ((channel < 10) ? 3 : 6), graph_baseline + 2);
    gfx->print(channel);
    if (ap_count_list[idx] > 0)
    {
      gfx->setCursor(offset - ((ap_count_list[idx] < 10) ? 9 : 12), graph_baseline + 8 + 2);
      gfx->print('{');
      gfx->print(ap_count_list[idx]);
      gfx->print('}');
    }
  }

  // Wait a bit before scanning again
  delay(SCAN_INTERVAL);
}