Interfacing Multiple DS18B20 Digital Temperature Sensors with Arduino

This project enables an Arduino Uno to monitor temperature from multiple DS18B20 digital temperature sensors simultaneously over a shared communication line. The system relies on the 1-Wire protocol, a bus architecture that allows multiple slave devices to communicate with a single master using just one data wire and a common ground. Each DS18B20 sensor leaves the factory with a unique 64-bit serial address laser-etched into its silicon, ensuring the Arduino can distinguish between individual units even when they are wired in parallel. Because the 1-Wire bus requires an open-drain topology to manage data collisions and signal integrity, a 4.7k ohm pull-up resistor must be connected between the data line and the 5V power rail. The Arduino board supplies power to the sensors via its 3.3V or 5V pins and communicates with them using the OneWire and DallasTemperature software libraries within the Arduino IDE. When queried, the master device sends commands along the bus to initiate temperature conversions across all attached sensors. Once the conversion is complete, the Arduino reads the digitized temperature data either by sequentially addressing each sensor's unique 64-bit ID or by referencing their physical index order on the shared bus. This multi-drop capability drastically reduces the number of microcontroller pins required when scaling up environmental sensing arrays.