DS18B20 with Arduino Nano

Wiring for the DS18B20 waterproof temperature probe on the Arduino Nano (ATmega328P, 5 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

DS18B20 pin	Role	Arduino Nano pin	Notes
VDD	Power	5V	Red wire
DQ	One-wire data	D2 (PD2)	Yellow (sometimes white) wire. Needs a 4.7 kΩ pull-up to 3.3 V
GND	Ground	GND	Black wire

Check before you power it on

Supply: 5 V from the 5V pin.

Test code (Arduino)

// Library: OneWire, DallasTemperature
#include <OneWire.h>
#include <DallasTemperature.h>

OneWire bus(2);  // needs a 4.7 kΩ pull-up from DQ to VDD
DallasTemperature sensors(&bus);

void setup() {
  Serial.begin(115200);
  sensors.begin();
  Serial.print("Sensors found: ");
  Serial.println(sensors.getDeviceCount());
}

void loop() {
  sensors.requestTemperatures();
  Serial.println(sensors.getTempCByIndex(0));
  delay(1000);
}

Arduino board: arduino:avr:nano. Clones with the old bootloader upload at 57600 baud: choose “ATmega328P (Old Bootloader)” if uploads fail.

Questions

Which Arduino Nano pins do I use for the DS18B20?

VDD → 5V, DQ → D2 (PD2), GND → GND.

Does the DS18B20 work with the Arduino Nano at 5 V?

Yes: the DS18B20 runs at 3.3-5 V and the Arduino Nano uses 5 V signals, so no level shifting is needed.

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full Arduino Nano pinout · DS18B20 waterproof temperature probe: all pins and data

The DS18B20 on other boards

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