Abstract: This paper introduces a large-scale fire temperature alarm system using the DS18B20 as the temperature sensing alarm element and the CAN bus as the backbone network. The hardware and software implementations of the system are described in detail, focusing on the DS18B20. Compared to a DS18B20 temperature alarm system using only a single bus, this system has advantages such as more measuring points, lower cost, convenient installation and maintenance, easy expansion, high reliability, and strong anti-interference capabilities. Keywords: 1-Wire, Single-bus, DS18B20, CAN bus, Intelligent node, SJA1000 Overview In recent years, numerous building fires have caused significant losses to people's lives and property. Many fires are caused by faults in the building's electrical wiring, such as short circuits, which cause the wires to overheat and ignite flammable materials such as the wire insulation. These circuits are often hidden inside walls, making it difficult to detect faults and fires. Once a fire starts, it spreads along the wires, making firefighting difficult and often leading to major disasters. If a temperature rise exceeding normal levels at the point of circuit failure can be detected in time before a fire occurs, an effective fire alarm can be issued to prevent losses. The DS18B20 digital thermometer chip, manufactured by Dallas Semiconductor, has the following characteristics: 1. Small size, allowing it to be attached to wires or electrical equipment for temperature measurement, and can be installed along with the wiring during building construction. 2. Employs a 1-Wire single-bus for simultaneous power supply and bidirectional data transmission, resulting in low power consumption and easy networking. A single single-bus, with simple pull-up configuration, can connect dozens of DS18B20 chips, with a length of up to 200 meters. For details, please click: A Large-Scale Temperature Alarm System Based on Single-Bus and CAN Bus