ESP32 DS18B20 address

gistfile1.txt

// Determine DS18B20 addresses (thanks ChatGPT)
//
// How to use
//
// In Arduino IDE, install OneWire and DallasTemperature (Library Manager).
//
// Wire all DS18B20 sensors in parallel on the same data line with a 4.7 kΩ pull-up from DQ to Vdd.
//
// Vdd → 3.3V or 5V
//
// GND → GND
//
// DQ → pin 2 (or change ONE_WIRE_BUS).
//
// Upload, open Serial Monitor at 115200 baud.
//
// You’ll get a numbered list of all addresses found. The loop then prints each sensor’s current temperature 
// alongside its address every 5 seconds—super handy for tagging which probe is which.

#include <OneWire.h>
#include <DallasTemperature.h>

// ==== CONFIG ====
// Data pin for the DS18B20 bus:
#define ONE_WIRE_BUS 2
// Max number of sensors you expect on the bus (adjust if needed)
#define MAX_SENSORS 20
// =================

OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

uint8_t foundAddrs[MAX_SENSORS][8];
int sensorCount = 0;

void printAddr(const uint8_t a[8]) {
  for (uint8_t i = 0; i < 8; i++) {
    if (a[i] < 16) Serial.print('0');
    Serial.print(a[i], HEX);
    if (i < 7) Serial.print(' ');
  }
}

bool isValidDS18B20(const uint8_t a[8]) {
  // Family code 0x28 for DS18B20
  if (a[0] != 0x28) return false;
  // Check CRC: last byte is CRC of first 7 bytes
  return OneWire::crc8(a, 7) == a[7];
}

void scanBusForSensors() {
  sensorCount = 0;
  oneWire.reset_search();
  uint8_t addr[8];

  while (oneWire.search(addr)) {
    if (sensorCount >= MAX_SENSORS) break;

    if (!isValidDS18B20(addr)) {
      Serial.print("Skipping non-DS18B20 or bad CRC: ");
      printAddr(addr);
      Serial.println();
      continue;
    }

    // Store the address
    for (uint8_t i = 0; i < 8; i++) {
      foundAddrs[sensorCount][i] = addr[i];
    }
    sensorCount++;
  }
}

void setup() {
  Serial.begin(115200);
  delay(200);
  Serial.println("\n=== DS18B20 Multi-Sensor Address Finder ===");
  Serial.println("Scanning 1-Wire bus...\n");

  scanBusForSensors();

  if (sensorCount == 0) {
    Serial.println("No valid DS18B20 sensors found. Check wiring and pull-up (4.7k).");
  } else {
    Serial.print("Found ");
    Serial.print(sensorCount);
    Serial.println(" DS18B20 sensor(s):");
    for (int i = 0; i < sensorCount; i++) {
      Serial.print("  [");
      Serial.print(i);
      Serial.print("] ");
      printAddr(foundAddrs[i]);
      Serial.println();
    }
  }

  // Init DallasTemperature so we can optionally read temps
  sensors.begin();
  // Optional: show if parasite power is detected
  Serial.print("\nParasite power: ");
  Serial.println(sensors.isParasitePowerMode() ? "ON" : "OFF");
  Serial.println("\nReading temperatures every 5s (press reset to rescan)...\n");
}

void loop() {
  if (sensorCount == 0) {
    delay(3000);
    return;
  }

  sensors.requestTemperatures();

  for (int i = 0; i < sensorCount; i++) {
    // Convert stored address into DeviceAddress type
    DeviceAddress da;
    for (uint8_t b = 0; b < 8; b++) da[b] = foundAddrs[i][b];

    float c = sensors.getTempC(da);
    Serial.print("[");
    Serial.print(i);
    Serial.print("] ");
    printAddr(foundAddrs[i]);
    Serial.print("  =>  ");
    if (c == DEVICE_DISCONNECTED_C) {
      Serial.println("Temp: DISCONNECTED");
    } else {
      Serial.print("Temp: ");
      Serial.print(c, 2);
      Serial.println(" °C");
    }
  }

  Serial.println();
  delay(5000);
}