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Nokia 5110 LCD with ESP32 DevKit V1 — direct 3.3 V wiring, Wi-Fi scanner

Wire a Nokia 5110 (PCD8544) to an ESP32 DevKit V1 on hardware SPI with no level shifting, set the contrast, and list nearby Wi-Fi networks by signal.

Arduino C++Verified — core esp32 3.3.12, Adafruit PCD8544 Nokia 5110 LCD library 2.0.3, 3 Nov 2026Compile-only

Community draft — report a mistake

The Nokia 5110 is a cheap 84×48 monochrome LCD with a low-power controller, the PCD8544. It suits battery gadgets and small status screens, and it is readable in daylight.

On the ESP32 DevKit V1 it is an easy fit: the display is a 3.3 V part, so all five signal lines connect directly — hardware SPI on D18/D23 and the control lines on D25, D26 and D27. The sketch turns the board into a pocket Wi-Fi scanner that lists the five strongest networks around you with their signal strength, refreshed every five seconds.

Wiring

ESP32 DevKit V1Only the pins used are shown · 3.3 V logicNokia 5110 LCD (84×48, PCD8544)330 ΩD25D26D27GNDD23D183V3RSTCEDCDINCLKVCCBLGND
Also needed: 330 Ω resistor for the backlight.
Every connection
ESP32 DevKit V1Nokia 5110 LCD (84×48, PCD8544)WireNotes
D25RSTorange
D27CEpurpleChip select. SCE on blue boards.
D26DCblue
D23DINgreenVSPI MOSI.
D18CLKyellowVSPI SCK.
3V3VCCredThe PCD8544 is a 3.3 V chip — a direct match for the ESP32.
GNDBLblackVia 330 Ω — Red boards light the backlight with BL to GND. Blue boards: BL through 330 Ω to 3V3 instead.
GNDGNDblack

3.3 V (2.7–3.3 V) part, 3.3 V board. The PCD8544 is a 3.3 V chip and its inputs are not 5 V tolerant. ESP32 and Pico connect directly. On an Uno power it from 3.3 V and drop the five signal lines through a level shifter (or 10 kΩ series resistors on RST, DC, DIN, CLK and 1 kΩ on CE as a quick fix).

Board quirks

  • Unlike on an Uno, no level shifting is needed: the ESP32’s 3.3 V logic is exactly what the PCD8544 expects, so all five signal wires go straight across.
  • The three-pin constructor Adafruit_PCD8544(DC, CS, RST) uses hardware SPI, which on the DevKit V1 means CLK on D18 and DIN on D23. RST, CE and DC can go on any free GPIO; D25–D27 keep the strapping pins (D2, D5, D12, D15) free.
  • Contrast is the usual problem. The sketch sets 55; if the screen is all grey or black lower it, if it is blank raise it. Values between 45 and 65 suit most modules, and the right one shifts a little with temperature.
  • The scan is passive: the ESP32 listens for beacons and never connects or sends data. The display has room for 14 characters × 6 lines, so names are cut to 9 characters next to the signal in dBm.
  • Backlight polarity differs between the red and blue boards. If the light stays off, move the 330 Ω resistor from GND to 3V3.

Code

nokia5110-esp32.inoArduino C++Open in PlaygroundOpen in PlaygroundFlash
// Nokia 5110 LCD (PCD8544) on an ESP32 DevKit V1 — pocket Wi-Fi scanner.
// Hardware SPI (VSPI): CLK → D18, DIN → D23. CE → D27, DC → D26, RST → D25.
// VCC → 3V3, GND → GND, BL → 330 Ω → GND (red boards; blue boards: BL via 330 Ω to 3V3).
// Lists the five strongest networks nearby (passive scan — it never connects or transmits data).
#include <WiFi.h>
#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>

constexpr int8_t LCD_DC = 26, LCD_CE = 27, LCD_RST = 25;
Adafruit_PCD8544 lcd(LCD_DC, LCD_CE, LCD_RST);  // 3-pin constructor = hardware SPI on D18/D23

void setup() {
  Serial.begin(115200);
  lcd.begin();
  lcd.setContrast(55);  // 45–65 suits most modules: too high = all black, too low = blank
  lcd.clearDisplay();
  lcd.setTextColor(BLACK);
  lcd.setCursor(0, 0);
  lcd.println("ESP32 + 5110");
  lcd.println("Scanning...");
  lcd.display();
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  Serial.println("Nokia 5110 ready — scanning Wi-Fi every 5 s");
}

void loop() {
  int n = WiFi.scanNetworks();
  // Pick the five strongest (the scan result is not guaranteed to be sorted).
  int order[5];
  int shown = 0;
  for (; shown < 5 && shown < n; shown++) {
    int best = -1;
    for (int i = 0; i < n; i++) {
      bool used = false;
      for (int k = 0; k < shown; k++) used |= order[k] == i;
      if (!used && (best < 0 || WiFi.RSSI(i) > WiFi.RSSI(best))) best = i;
    }
    order[shown] = best;
  }
  lcd.clearDisplay();
  lcd.setCursor(0, 0);
  lcd.printf("%d networks\n", n);  // 14 characters × 6 lines on 84 × 48 pixels
  Serial.printf("%d networks\n", n);
  for (int k = 0; k < shown; k++) {
    int i = order[k];
    String ssid = WiFi.SSID(i);
    if (ssid.isEmpty()) ssid = "(hidden)";
    lcd.printf("%4ld %.9s\n", (long)WiFi.RSSI(i), ssid.c_str());
    Serial.printf("  %4ld dBm  ch %2ld  %s\n", (long)WiFi.RSSI(i), (long)WiFi.channel(i), ssid.c_str());
  }
  lcd.display();
  WiFi.scanDelete();
  delay(5000);
}

Library: Adafruit PCD8544 Nokia 5110 LCD library (Adafruit (also install Adafruit GFX Library)) — compiled with Adafruit PCD8544 Nokia 5110 LCD library 2.0.3.

Expected serial output

Serial Monitor · 115200Output
Nokia 5110 ready — scanning Wi-Fi every 5 s
7 networks
   -42 dBm  ch  6  FlatNo12_5G
   -67 dBm  ch 11  JioFiber-xyz
   -71 dBm  ch  1  ACT_Home
   -80 dBm  ch  6  (hidden)
   -88 dBm  ch  3  AirtelXstream

Common errors

Screen is completely black or completely blank

Contrast. Change setContrast(55) in steps of 5 until text appears.

Backlight works but nothing is drawn

DIN and CLK swapped, or not on D23/D18. Hardware SPI only uses those two pins.

Text is garbled or shifted after a few minutes

A loose RST or DC wire. Breadboard jumpers on these displays are often marginal — push the module firmly into the breadboard or solder header pins.

↑↓ to move · Enter to open