One of the projects I wanted to build for some time was a Modular Weather Station. Modular in the sense that we can add the sensors we want just by changing the software.

The Modular Weather Station is divided in three parts. The main board has the Wemos, the battery, the connection to the solar panel, the charger and the ADC (Analog-Digital converter). The first satellite pcb manages the analog connections and the second satellite pcb manages the digital. They are connected with UTP cat5 cable and RJ45 sockets.

The data is transmitted to a MQTT Server. The Homeassistant read from there, show on dashboard and stores for statistic.

Supplies

Wemos D1 Mini - 1
DHT22 - 1
BMP180 - 1
Jumper Cables
18650 battery - 1
18650 holder -1
Female Headers
Male Headers
RJ45 female socket - 4
IP68 PG7 Cable connector - 2
TP4056 - 1
6W Solar Panel - 1
Waterproof cases - 2
PCB
UTP Cat 5 Cable
16 pin IC Socket - 1
MCP3008 (Future use) - 1

Step 1: Assembly

I initially checked that the solar panel provides enough power. Then I started building the prototype. This version will be powered by a 18650 battery being charged by the solar panel. It will monitor the humidity, temperature, pressure and voltage of the battery itself. All of this will be controlled by a Wemos D1 Mini and the data will be transmitted to an MQTT server. After uploading the program to Wemos, I confirmed the power and tested it’s operation.

Step 2: Code and Schema

All the code and PCB schemas are available on my GitHub.

Step 3: PCB

Then I drew the pcb in Autodesk Eagle. This has a free version that allows you to design pcb's with two layers and 80cm2 of area. After drawing the schematic, it generates the footprints of the components. Just make the connections and place them in the desired location.

Finally, it’s necessary to generate Gerber files to send to PCBway.

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Step 4: Box

After welding all the components, I started building the box. For that I used a waterproof case that I had. I installed a Waterproof cable connector to pass the connection to the sensors and designed a support for the installation of a filter in Autodesk Fusion 360. This filter allows air to circulate, preventing condensation and preventing foreign objects from entering. I also designed supports for the pcb and the solar panel. After installing the solar panel I started building the box where the sensors will be stored being the procedure similar to the main box.

After connecting all the components, I installed a fixing bracket in the box.

Then I installed the filters in both boxes. These consist of a piece of fabric stuck between two printed supports.

Step 5: Instalation and Testing

Finally, I installed the weather station outside and checked the data. At the moment only is working the digital sensors. In the future i'm planning adding more digilal sensors (UV sensor, ...) and analog sensors ( an anemometer, ...).

I hope you like this project. I’ve got other projects videos so check those out and don’t forget to subscribe my channel and follow me at the social networks.