Raspberry Pi

Guide to using a Raspberry Pi as a 3D-PAWS data logger for flexible deployments with local logging and optional remote connectivity.

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. 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

Sensors Supported

• Light sensor

• Rain Gauge

• Anemometer

• Wind Vane

• Radiation Shield (Temperature, Pressure, & Relative Humidity)

Download the 3D-PAWS software

GitHub - 3d-paws/3D-PAWS-Raspberry-Pi: A python library used to run a 3D-PAWS weather station.GitHub

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

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.

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.