MicroMod Weather Carrier Board Hookup Guide

Contributors: El Duderino, MAKIN-STUFF

Hardware Overview

In this section we'll cover the various hardware, sensors and adjustable solder jumpers on the MicroMod Weather Carrier Board, the external sensor connections and the pinout of the Carrier Board for a detailed look at how it connects to your chosen MicroMod Processor.

Common Components

Most SparkFun MicroMod Carrier Boards will have some common components and all MicroMod Carrier Boards will have the keyed M.2 MicroMod Connector to plug your processor into. The photo and list below outline some of the components you can expect on the Weather Carrier Board and most other SparkFun MicroMod Carrier Boards.

• M.2 MicroMod Connector - This special keyed M.2 connector lets you install your MicroMod Processor of choice on your Weather Carrier Board.
• USB-C Connector - Connect to your computer to program your processor and also can provide power to your MicroMod system.
• 3.3V Regulator - Provides a regulated 3.3V and sources up to 1A.
• Qwiic Connector - The standard Qwiic connector so you can add other Qwiic devices to your MicroMod system.
• Boot/Reset Buttons - Push buttons to enter boot mode on processors and to reset your MicroMod circuit.
• RTC Backup Battery & Charge Circuit - 1mAh backup battery for the Real-Time Clocks on MicroMod Processors that have a built-in RTC. Receives charge voltage from 3.3V.
• microSD Slot - Insert a microSD card formatted to FAT32 here to log your weather data.

Weather Station Sensors and External Sensor Connections

As we mentioned in the introduction, the board comes with a BME280 Temperature, Pressure and Humidity Sensor, a VEML6075 UV Light Sensor and a AS3935 Lightning Detector. Along with those on board sensors there is a three pin latch terminal for a soil moisture sensor as well as a pair of RJ11 jacks for connecting wind and rain meters.

The three on board sensors paired with the external sensors allows for a powerful and customizable weather tracking tool.

BME280 Temperature, Pressure and Humidity Sensor

The BME280 Atmospheric Sensor from Bosch is the heavy lifter of the Weather Carrier Board. The BME280 is a highly-accurate, digital environmental sensor that measures ambient temperature, relative humidity and barometric pressure.

The BME280 measures humidity from 0 to 100% with an absolute accuracy of ±3 %RH (from 20-80%RH), temperatures between 0°C to 65°C with an absolute accuracy of ±0.5-1.5°C (full temperature range is -40°C to 85°C) and atmospheric pressures between 300 to 1100hPa with an absolute accuracy of ±1hPa (relative accuracy of ±0.12hPa). The I²C address of the BME280 is 0x77.

For detailed information on the sensor's functionality and characteristics, refer to the BME280 Datasheet or our Hookup Guide for the SparkFun Qwiic Atmospheric Sensor (BME280).

VEML6075 UV Sensor

The VEML6075 UV light sensor from Vishay Semiconductors measures UVA (320-400 nm, peak @365 ±10nm ) and UVB (228-320 nm, peak @330 ±10nm) irradiance so you can calculate the UV Index at your Weather Station. Example 4 - Calculate UVI in the SparkFun VEML6075 Arduino Library demonstrates how to calculate that index using this sensor.

The VEML6075 has a UVA resolution of 0.93 counts/µW/cm² and a UVB resolution of 2.1 counts/µW/cm². The I²C address is 0x10.

For more information about this UV sensor, refer to the VEML6075 datasheet or our Hookup Guide for the SparkFun Qwiic UV Sensor (VEML6075).

AS3935 Lightning Detector

The AS3935 Lightning Detector from AMS can detect lightning strikes up to 40km away with an accuracy of up to 1km from the storm front. The specially-tuned antenna picks up lightning events in the 500kHz band and a built-in algorithm helps check the incoming signal pattern to reject potential man-made disturbers such as DC/DC converters in large appliances.

The AS3935 Lightning Detector is connected to the primary SPI bus and Chip Select (CS) for the AS3935 is tied to G1/Bus1 (MicroMod pad 42).

For in-depth information about the sensor, refer to the AS3935 Datasheet or our Hookup Guide for the SparkFun Lightning Detector Breakout.

Soil Moisture Sensor Latch Terminal

The three-pin latch terminal makes it easy to connect a Soil Moisture Sensor to your Weather Carrier Board. The soil moisture sensor is a handy addition to the Weather Carrier Board if you are using it in something like a greenhouse environment to keep an eye on your soil and, with some slick coding, you could even turn an irrigation system on or off depending on the sensor's measurements.

The Soil Moisture Sensor has two large coated pads that act as prongs for what is essentially a large variable resistor. The sensor takes advantage of a simple concept of moist soil being more conductive than dry soil so as more water is added to the soil, the resistance of the circuit drops and the SIG output increases.

Power (3.3V) for the sensor is provided by G0 (MicroMod pad 40) allowing you to turn it on and off easily (continuous power is not recommended for the soil moisture sensor) and the Signal output is tied to A0 (MicroMod pad 34).

If you are looking for some inspiration for an automated watering project, check out our Product Showcase Video and the Soil Moisture Sensor Hookup Guide.

Wind and Rain RJ11 Connectors

The two RJ11 connectors allow you to connect the wind and rain sensors included with our Weather Meters Kit to monitor wind speed, wind direction and rainfall. These two sensors are great additions to an outdoor Weather Carrier Board setup to get a more complete view of weather in the area.

The Weather Meters Kit includes an anemometer to measure wind speed, a wind vain to determine wind direction and a self-emptying tipping bucket collector to monitor rainfall. The anemometer outputs a digital signal tied to D0 (MicroMod pad 10). The wind vain outputs an analog signal relative to its position tied to A1 (MicroMod pad 38). The rainfall detector outputs a digital signal to D1 (MicroMod pad 18).

For help assembling and testing your Weather Meters Kit, check out our Weather Meter Hookup Guide.

Plated Through-Hole Headers

The Weather Carrier Board also routes several pins from a connected MicroMod Processor to a pair of plated through-hole (PTH) headers.

On the "North"/Top of the board, the primary SPI bus is routed to a PTH header (the CS pin on this header is routed to G2/BUS2), a trio of Ground pins and both PWM1 & PWM0 if users wish to solder components that can use pulse-width modulation.

The "South"/Bottom of the board features both Serial UARTs (UART1 & UART2), another pair of Ground pins as well as 3.3V and SDA/SCL from the primary I²C bus if users prefer to have a soldered connection for I²C devices instead of the Qwiic connector.

Solder Jumpers

There are a total of seven adjustable solder jumpers on the MicroMod Weather Carrier Board labeled I²C, MEAS, BYP, VE, UV, 5V and 3V3. The table below briefly outlines their functionalities:

MicroMod Pinout

Since this carrier board is designed to work with all of the MicroMod Processors we've included the table below to outline which pins are used so, if you would like, you can compare them to the pinout tables in their respective Hookup Guides.

• Weather Carrier Board Pinout Table
• MicroMod General Pinout Table
• MicroMod General Pin Descriptions

Board Dimensions

The Weather Carrier Board measures 2.65" x 2.30" (67.31mm x 58.42mm) and has four mounting holes that fit a standard 4-40 screw.