> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/wokwi/wokwi-docs/llms.txt
> Use this file to discover all available pages before exploring further.

# DS18B20 Temperature Sensor

> Digital temperature sensor with 1-Wire interface

Digital temperature sensor with 1-Wire interface.

## Pin names

<ParamField path="VCC" type="Power">
  Positive voltage
</ParamField>

<ParamField path="DQ" type="Digital I/O">
  1-Wire data line (input/output)
</ParamField>

<ParamField path="GND" type="Ground">
  Ground
</ParamField>

## Attributes

<ParamField path="temperature" type="string" default="22">
  Initial temperature value (celsius)
</ParamField>

<ParamField path="deviceID" type="string" default="010203040506">
  12-character hex device ID for the 1-Wire address
</ParamField>

<ParamField path="familyCode" type="string" default="28">
  1-Wire family code
</ParamField>

## Controlling the temperature

You can change the temperature value while the simulation is running.
Click on the DS18B20 sensor and a small popup window will open. Use the temperature
slider to change the value.

The temperature range is -55°C to 125°C.

## Multiple sensors

You can connect multiple DS18B20 sensors to the same data pin. Each sensor must have
a unique `deviceID` attribute. The 1-Wire protocol allows addressing individual sensors
by their unique ID.

Example with three sensors:

```json theme={null}
{
  "parts": [
    { "type": "wokwi-ds18b20", "id": "temp1", "attrs": { "deviceID": "111111111111" } },
    { "type": "wokwi-ds18b20", "id": "temp2", "attrs": { "deviceID": "222222222222" } },
    { "type": "wokwi-ds18b20", "id": "temp3", "attrs": { "deviceID": "333333333333" } }
  ]
}
```

## Arduino code example

```cpp theme={null}
#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 2

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

void setup() {
  Serial.begin(115200);
  sensors.begin();
}

void loop() {
  sensors.requestTemperatures();
  float tempC = sensors.getTempCByIndex(0);
  Serial.print("Temperature: ");
  Serial.print(tempC);
  Serial.println(" °C");
  delay(1000);
}
```

<Warning>
  The DallasTemperature library cannot read temperatures of exactly -55°C due to
  a limitation in how the library detects disconnected sensors. If you need to read
  this specific temperature, use the OneWire library directly.
</Warning>

## Automation controls

The temperature sensor can be controlled using [Automation Scenarios](/wokwi-ci/automation-scenarios). It exposes the following controls:

<ParamField path="temperature" type="float">
  Set the temperature value in Celsius (between -55 and 125)
</ParamField>

## Simulator examples

* [DS18B20 single sensor](https://wokwi.com/projects/453964849658651649) - Basic temperature reading with DallasTemperature library
* [DS18B20 multiple sensors](https://wokwi.com/projects/453940154220493825) - Multiple sensors on a single bus