OpenString is the world's first open-source temperature string for environmental monitoring. It consists of a PCB design, firmware package, and assembly guide to help you bring temperature profile monitoring into any project.
Based on the production temperature string used by SIMB3, OpenString is an extensible, arctic-hardened design that can be used as-is or tailored to your specific application.
Along with this documentation, the OpenString repository contains the version-controlled design files for the hardware, firmware, and documentation. The licenses permit commercial use and adaptation, provided you preserve attribution and share modifications under the same terms.
Getting Started
OpenString is designed to be accessible to anyone with basic electronics experience. It consists of three main components:
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The PCB: a 40 cm × 1.6 cm PCB populated with 20 temperature sensors at 2 cm spacing. The PCB has castellated edges at both ends so multiple boards can be soldered end-to-end into a continuous string of any length.
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Sample Firmware: code that demonstrates how to interact with the hardware, including reading the sensor bus and logging the temperatures. The firmware provided is in Arduino, but can be adapted to any language you prefer.
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Environmental packaging — recommendations for sealing, potting, cabling, and packaging the string for your deployment. Hardening depends on your application, so we provide guidelines and examples rather than a one-size-fits-all solution.
Why Open-Source?
Temperature strings are hard. They are delicate, expensive, and temperamental. Over the years, we've developed a series of solutions for SIMB3 that have proven themselves in arctic conditions. Rather than gatekeep this knowledge, we've decided to share it with the community with the hope that it starts a conversation and moves the field forward.