Documentation

// DS18B20 - Read temperature on Arduino
// Wire: Red=5V, Black=GND, Yellow=D2 with 4.7k pull-up to 5V
// Install libraries: OneWire, DallasTemperature

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

const int ONE_WIRE_BUS = 2;
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

void setup() {
  Serial.begin(9600);
  sensors.begin();
}

void loop() {
  sensors.requestTemperatures();
  float c = sensors.getTempCByIndex(0);
  float f = c * 9.0 / 5.0 + 32.0;

  Serial.print("Temp: "); Serial.print(c, 2); Serial.print(" C  /  ");
  Serial.print(f, 2); Serial.println(" F");
  delay(1000);
}

// DS18B20 - Multiple probes sharing one data wire
// All sensors share Red, Black, Yellow; one 4.7k pull-up for the whole bus

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

OneWire oneWire(2);
DallasTemperature sensors(&oneWire);

void setup() {
  Serial.begin(9600);
  sensors.begin();
  Serial.print("Found "); Serial.print(sensors.getDeviceCount()); Serial.println(" sensors");
}

void loop() {
  sensors.requestTemperatures();
  for (int i = 0; i < sensors.getDeviceCount(); i++) {
    Serial.print("Sensor "); Serial.print(i); Serial.print(": ");
    Serial.print(sensors.getTempCByIndex(i)); Serial.println(" C");
  }
  Serial.println("---");
  delay(2000);
}

#!/usr/bin/env python3
# DS18B20 on Raspberry Pi via 1-Wire kernel driver
# Enable 1-Wire first: sudo raspi-config -> Interface Options -> 1-Wire

import glob, time

base = "/sys/bus/w1/devices/"
device = glob.glob(base + "28-*")[0] + "/w1_slave"

def read_temp():
    with open(device, "r") as f:
        lines = f.readlines()
    while not lines[0].strip().endswith("YES"):
        time.sleep(0.2)
        with open(device, "r") as f:
            lines = f.readlines()
    pos = lines[1].find("t=")
    if pos != -1:
        return float(lines[1][pos+2:]) / 1000.0
    return None

while True:
    c = read_temp()
    print("Temp: {:.2f} C  /  {:.2f} F".format(c, c * 9/5 + 32))
    time.sleep(1)

# DS18B20 on Raspberry Pi Pico (MicroPython)
# Wire: Red=3V3, Black=GND, Yellow=GP15 with 4.7k pull-up to 3V3

from machine import Pin
import onewire, ds18x20, time

ow = onewire.OneWire(Pin(15))
ds = ds18x20.DS18X20(ow)

roms = ds.scan()
print("Found", len(roms), "DS18B20 sensors")

while True:
    ds.convert_temp()
    time.sleep_ms(750)
    for rom in roms:
        c = ds.read_temp(rom)
        print("{}: {:.2f} C".format(bytes(rom).hex(), c))
    time.sleep(1)