> For the complete documentation index, see [llms.txt](https://3dpaws.comet.ucar.edu/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://3dpaws.comet.ucar.edu/building-3d-paws/adding-additional-instruments/snow-gauge.md). # Snow Gauge Build guide for a non-contact snow depth sensor using ultrasonic and temperature compensation. ### How the Sensor Works The snow gauge in the 3D-PAWS system measures snow depth using a combination of ultrasonic and temperature sensing technologies. Mounted above the ground, the MaxBotix HRXL-MaxSonar-WRLS ultrasonic sensor emits high-frequency sound pulses toward the snow surface. These pulses reflect off the snow, and the sensor measures the time it takes for the echo to return. By calculating this time and accounting for the speed of sound in air, the system determines the distance from the sensor to the snow surface. As snow accumulates, this distance decreases, allowing for continuous tracking of snow depth. To ensure accurate measurements in all weather conditions, the system uses an external MB79XX HR-MaxTemp temperature sensor. This sensor monitors the air temperature near the ultrasonic sensor, allowing the system to automatically adjust for changes in the speed of sound caused by temperature fluctuations. This dual-sensor approach provides reliable, real-time snow depth data, even during periods of rapid temperature change. ### Instruction Slides for Assembling the Snow Gauge {% embed url="" %} --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://3dpaws.comet.ucar.edu/building-3d-paws/adding-additional-instruments/snow-gauge.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.