> 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/setting-up-the-data-logger/raspberry-pi.md). # Raspberry Pi The Raspberry Pi 3B+ paired with a Grove Base Hat is used as a flexible data logger for the following sensors: **light, temperature, humidity, pressure, wind speed/direction, and rainfall** utilizing the [3D-PAWS Python library](https://github.com/3d-paws/3D-PAWS-Raspberry-Pi). This setup supports both cellular and Wi-Fi connectivity for remote data transmission. The Grove Hat simplifies sensor connections via I2C, UART, or analog ports, while an optional cellular modem can be added for 2G/LTE connectivity. Data is stored locally on an SD card as a backup if cellular or Wi-Fi fails. The 3D-PAWS library provides pre-built scripts for sensor polling and data logging, ### Instruction Slides for Assembling the Data Logger {% embed url="" %} ### Sensors Supported * Light sensor * Rain Gauge * Anemometer * Wind Vane * Radiation Shield (Temperature, Pressure, & Relative Humidity) ### Download the 3D-PAWS software {% embed url="" %} ## Raspberry Pi Data Logger Architecture A Raspberry Pi acts as a full local computer that collects sensor data and transmits it directly to data services. ``` Sensors ↓ Raspberry Pi Data Logger ↓ Local Storage (SD Card) ↓ WiFi / Cellular Modem ↓ CHORDS Data Portal ↓ Grafana Visualization ``` Because the Raspberry Pi runs Linux, it can also perform: * local data processing * advanced sensor integration * custom software execution {% hint style="info" %} ### Note: The Raspberry Pi 3B+ and 4 models require significantly more power than microcontroller-based options like the Particle Boron. While the Particle Boron can operate efficiently on the smaller Voltaic solar panels and batteries we recommended, the Raspberry Pi 3B+ and 4 typically need a much larger solar panel and battery setup to ensure reliable, continuous operation-especially in remote or off-grid deployments. See below for power requirements and recommendations. {% endhint %} ## Raspberry Pi 3B+ System Power Budget | **Component** | **Function** | **Supply Voltage** | **Avg. Current (mA)** | **Peak Current (mA)** | **Notes** | | -------------------------- | --------------------------------------------------- | ------------------- | --------------------- | --------------------- | -------------------------------- | | **Raspberry Pi 3B+** | SBC, data logging, control | 5 V | 400 | 950 | WiFi on, HDMI/LEDs off | | **Grove Base HAT** | GPIO expansion, Grove interface | 3.3 V | 5 | 5 | Enables Grove sensors | | **Adafruit BMP390** | Pressure & altimeter sensor | 3.3 V | 0.8 | 0.8 | I2C, always on | | **Adafruit SHT31-D** | Temp & humidity sensor | 3.3 V | 0.5 | 0.5 | I2C, always on | | **Adafruit MCP9808** | High-accuracy temp sensor | 3.3 V | 0.2 | 0.2 | I2C, always on | | **AS5600** | Rotational position sensor for wind vane | 3.3 V | 4.5 | 4.5 | I2C, always on | | **SI1145** | UV/IR/Visible light sensor | 3.3 V | 0.4 | 0.4 | I2C, always on | | **2 × SS451A Hall Effect** | Magnetic switch sensors for rain gauge & anemometer | 3.3 V | 9.0 | 9.0 | Each \~4.5 mA, always on | | **Buck Converter** | Voltage regulation | 12–18 V in, 5 V out | — | — | Assume 85% efficiency | | **Total System** | — | — | **420.4** | **970.4** | All sensors powered continuously | ### System Power Profile **Average Power Consumption:** * 420.4 mA × 5 V = 2.10 W With 85% buck converter efficiency: * 2.10 W ÷ 0.85 ≈ 2.47 W drawn from the battery **Peak Power Consumption:** * 970.4 mA × 5 V = 4.85 W With 85% buck converter efficiency: * 4.85 W ÷ 0.85 ≈ 5.71 W drawn from the battery **Solar Panel:** * A 20 W panel provides ample margin for continuous operation and battery charging. **Battery Sizing (example, 12 V system):** For 24 hours runtime at 2.47 W average: * 2.47 W × 24 h = 59.3 Wh **For a 12 V battery:** * 59.3 Wh ÷ 12 V ≈ 4.94 Ah **Add a Safety Margin** Add at least 30% extra for cloudy days, battery aging, and inefficiency: * 4.94 Ah × 1.3 ≈ 6.4 Ah **Choose a Standard Battery Size** * **Recommended minimum:** 12V, 7Ah battery (common size) * ***For more backup (2–3 days), consider a 12V, 12–20Ah battery*** > **Notes:** > > * Pi 3B+ current draw is measured with HDMI and LEDs off, WiFi enabled, and no USB peripherals. > * All sensors are I2C and powered from the Pi’s 3.3 V rail via Grove HAT. > * Actual current draw may vary with workload and peripherals. --- # Agent Instructions This documentation is published with GitBook. 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