The DS1921, also known as the Thermochron iButton, is a rugged, self-sufficient system that records temperature data. Manufactured by Dallas Semiconductor (now Maxim Integrated), it combines a unique silicon serial number, a real-time thermometer, and a logger in a robust, button-shaped package.

Applications

• Cold chain monitoring (e.g., vaccine transport, food storage)
• Environmental monitoring
• HVAC system performance analysis
• Transportation monitoring
• Equipment temperature logging

Features

• Digital Thermometer: Measures temperature with high accuracy.
• Data Logging: Stores temperature readings at user-programmable intervals.
• Unique Identification: Each iButton has a unique 64-bit serial number for traceability.
• Rugged Package: Durable stainless steel "iButton" package resists harsh environments.
• Battery Powered: Self-contained power source for autonomous operation.
• Memory: Stores temperature data and alarm settings.

Benefits

• Accurate Temperature Measurement: Provides reliable and accurate temperature readings.
• Automated Data Logging: Eliminates the need for manual temperature recording.
• Easy Deployment: Simple to attach to objects or surfaces for monitoring.
• Tamper-Proof: Rugged package prevents tampering with the data.
• Long Battery Life: Can operate for extended periods without battery replacement.
• Traceability: Unique serial number allows for tracking individual iButtons and their data.

Additional Details

The DS1921 communicates with a host system via the 1-Wire protocol. Data can be downloaded and analyzed using specialized software. The sampling rate and alarm thresholds are programmable. Refer to the datasheet from Maxim Integrated for detailed technical specifications and programming information. The battery life is dependent on the logging interval and operating temperature. The device stores the data in internal memory. Once the memory is full, older data will be overwritten.