WiFi Network Scanner
with Signal Bars

No extra libraries needed — WiFi.h is part of the ESP32 Arduino core. Layout:

Networks sorted by RSSI descending (strongest first). Alternating row background colours for readability. SSID truncated to 15 chars with a ~ suffix if longer.

Signal bars: 5 bars, each 5 px wide, progressively taller (5, 9, 13, 17, 21 px). Filled bars coloured by signal quality; unfilled bars drawn as outlines in grey:

Lock icon: drawn as a filled rounded rectangle (body) + an open shackle arc + a small keyhole cutout — all in orange (0xFD20) for visibility on any row background.

void drawBars(int x, int y, int rssi) {
  int bars = (rssi >= -50) ? 5 : (rssi >= -60) ? 4 :
             (rssi >= -70) ? 3 : (rssi >= -80) ? 2 : 1;
  uint16_t color = (rssi >= -60) ? COL_GREEN :
                   (rssi >= -75) ? COL_YELLOW : COL_RED;
  for (int i = 0; i < 5; i++) {
    int bh = 5 + i * 4;
    if (i < bars) tft.fillRect(x+i*7, y+(20-bh), 5, bh, color);
    else          tft.drawRect(x+i*7, y+(20-bh), 5, bh, COL_GRAY);
  }
}

Added a 6-second auto-rescan cycle. The header updates every second with a countdown: <6s, <5s, etc. On scan start the header immediately shows "scanning…" and a "Scanning…" overlay fills the network area.

WiFi.scanNetworks() is a blocking call (~1–3 s), so the UI freezes during the scan — that's expected on a single-threaded Arduino sketch. The display returns instantly when the scan completes.

void loop() {
  unsigned long now = millis();
  if (now >= nextScan) {
    doScan();  // blocking, ~1-3s
  } else {
    static unsigned long lastTick = 0;
    if (now - lastTick >= 1000) {
      lastTick = now;
      drawHeader((int)(nextScan - now));  // update countdown
    }
  }
}

Wrote flash-sketch-006-wifi-scanner.sh. Only TFT_eSPI and the built-in WiFi.h — no additional library installs needed.

./flash-sketch-006-wifi-scanner.sh

# Sketch uses 27% of flash, 11% of RAM
# Wrote 278528 bytes at 0x00010000 in 3.5 seconds
# Hash of data verified.
# Hard resetting via RTS pin...

# First scan: 14 networks found
# Strongest: MyNetwork (-42 dBm, ch 6, locked)