In this Instructable, I am going to show you how to build a Solar powered WiFi Weather Station with a Wemos board. The Wemos D1 Mini Pro has a small form-factor and a wide range of plug-and-play shields make it an ideal solution for quickly getting started with programming the ESP8266 SoC. It is an inexpensive way to build the Internet Of Things ( IoT ) and is Arduino compatible.

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Update On 11.10.2022

Instructables Link for Weather Station V4,0: https://www.instructables.com/Solar-Powered-WiFi-Weather-Station-V40/

You can also look at my new version- 3.0 Weather Station.

You can also look at my new version-2.0 Weather Station.

You can buy V2.0 PCB from PCBWay.

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The new Weather Station has the following features:

1. The Weather Station can measure: Temperature, Humidity, Barometric Pressure, Altitude

2. You can monitor the above weather parameters from your Smartphone or from the web ( ThingSpeak.com )

3. The whole circuit along with the power supply is put inside a 3D printed enclosure.

4. The range of the device is enhanced by using a 3dBi external antenna. It is around 100 meters.

Step 1: Parts and Tools Required

1. Wemos D1 Mini Pro (Amazon / Banggood )

2. TP 4056 Charging Board ( Amazon / Aliexpress )

3. Diode ( Aliexpress )

4. BME 280 sensor ( Aliexpress )

5. Solar Panel ( Banggood )

6. Perforated Board ( Banggood )

7. Screw Terminals ( Banggood )

8. PCB standoffs ( Banggood )

9. Li Ion Battery ( Banggood )

10. AA Battery Holder ( Amazon )

11. 22 AWG wire ( Amazon / Banggood )

12. Super Glue ( Amazon )

13. Duct Tape ( Amazon )

14. 3D printing filament -PLA ( GearBest )

Tools Used :

1.3D Printer ( Anet A8 / Creality CR-10 Mini )

2. Soldering Iron ( Amazon )

3. Glue Gun ( Amazon )

4. Wire Cutter / Stripper ( Amazon )

Step 2: Power Supply

My plan is to deploy the Weather station at a remote place ( my farmhouse).To run the Weather Station continuously, there must be a continuous power supply otherwise the system will not work. The best way to provide continuous power to the circuit is by using a battery. But after some days the battery juice will run out, and it is a really difficult job to go there and charge it. So a solar charging circuit was proposed to user free energy from the sun to charge the batteries and to power the Wemos board. I have used a 14450 Li-Ion battery instead of a 18650 battery because of its smaller size. The size is the same as of an AA battery.

The battery is charged from a Solar panel through a TP4056 charging module. The TP4056 module comes with battery protection chip or without the protection chip. I will recommend buying a module which has a battery protection chip included.

About the TP4056 Battery Charger

The TP4056 module is perfect for charging single cell 3.7V 1 Ah or higher LiPo cells. Based around the TP4056 charger IC and DW01 battery protection IC this module will offer 1000 mA charge current then cut off when charging is finished. Furthermore, when the battery voltage drops below 2.4V the protection IC will cut off the load to protect the cell from under voltage. It also protects against overvoltage and reverse polarity connection.

Step 3: Measuring the Weather Data

In the earlier days, weather parameters like ambient temperature, humidity, and barometric pressure were measured with separate analog instruments: thermometer, hygrometer, and barometer. But today the market is flooded with cheap and efficient digital sensors that can be used to measure a variety of environmental parameters. The best examples are sensors like DHT11, DHT 22, BMP180, BMP280, etc.

In this project, we will use a BMP 280 sensor.

BMP 280 :

BMP280 is a sophisticated sensor that very accurately measures barometric pressure and temperature with reasonable accuracy. The BME280 is the next-generation of sensors from Bosch and is the upgrade to the BMP085/BMP180/BMP183 - with a low altitude noise of 0.25m and the same fast conversion time.

The advantage of this sensor is that it can use either I2C or SPI for communication with the microcontroller. For simple easy wiring, I will suggest to buy I2C version board.

Step 4: Using an External Antenna ( 3dBi )

The Wemos D1 mini Pro board have an inbuilt ceramic antenna along with provision for connecting an external antenna to improve the range. Before using the external antenna, you have to reroute the antenna signal from the built-in ceramic antenna, to the external socket. This can be done by rotating the small surface mount (0603) Zero Ohm resistor (sometimes called a link).

You can watch this video made by Alex Eames to rotate the zero ohm resistor.

Then snap the antenna SMA connector into the Wemos Pro mini antenna slot.

Step 5: Solder the Headers

Wemos modules come with a variety of headers but you have to solder it according to your requirement.

For this project,

1. Solder the two male headers to the Wemos D1 pro mini board.

2. Solder a 4 pin male header to the BMP 280 module.

After soldering the headers the module will look as shown in the above picture.

Step 6: Adding Headers and Terminals

Next step is soldering the headers to the perforated board.

1. First, place the Wemos board over the perforated board and mark the footprint. Then solder the two row of female headers over the marked position.

2. Then solder a 4 pin female headers as shown in the picture.

3. Solder screw terminals for battery connection.

Step 7: Mount the Charging Board :

Stick a small piece of double-sided tape on the back side of the charging module and then paste it on the perforated board as shown in the picture. During mounting care should be taken to align the board in such a way that the soldering holes will match with the perforated board holes.

Adding terminal for Solar Panel

Solder a screw terminal just near the micro USB port of the charging board.

You can solder this terminal in the earlier step also.

Step 8: Wiring Diagram

First I cut small pieces of different colors wires and strip out the insulation at both ends.

Then I solder the wires according to the Schematic diagram as shown in the above picture.

Wemos -> BME 280

3.3 V - -> Vin

GND --> GND

D1 --> SCL

D2 --> SDA

TP4056 Connection

Solar Panel terminal -> + and - near the micro USB port

Battery Terminal -> B+ and B-

5V and GND of Wemos -> Out+ and Out-

Note :The diode connected to the solar panel ( shown in the schematic ) is not required as the TP4056 module have in built diode at the input.

Step 9: Designing the Enclosure

This was the most time-consuming step for me. I have spent around 4 hours to design the enclosure. I used Autodesk Fusion 360 to design it. The enclosure has two parts: Main Body and Front Cover

The main body is basically designed to fit all the components. It can accommodate the following components

1. 50x70mm circuit board

2. AA battery holder

3. 85.5 x 58.5 x 3 mm Solar Panel

4. 3dBi external antenna

Download the .stl files from Thingiverse

Step 10: 3D Printing

After completion of the design, it is time to 3D print the enclosure. In Fusion 360 you can click on the make and slice the model by using a slicer software. I have used Cura to slice the model.

I used an Anet A8 3D printer and 1.75 mm green PLA to print out all the body parts. It took me about 11 hours to print the main body and around 4 hours to print the front cover.

I will highly recommend using another printer for you that is Creality CR - 10. Now a mini version of the CR-10 is also available. The Creality printers are one of my favorite 3D Printer.

As I am new to 3D designing, my design was not optimistic. But I am sure, this enclosure can be made by using lesser material ( less print time ). I will try to improve the design later.

My settings are:

Print Speed : 40 mm/s

Layer Height: 0.2

Fill Density: 15%

Extruder Temperature: 195 deg C

Bed Temp: 55 deg C

Step 11: Installing the Solar Panel and Battery

Solder a 22 AWG red wire to the positive terminal and black wire to the negative terminal of the Solar panel.

Insert the two wires into the holes in the roof of the main enclosure body.

Use super glue to fix the Solar Panel and press it some time for proper bonding.

Seal the holes from the inside by using hot glue.

Then insert the battery holder into the slot at the bottom of the enclosure.

Step 12: Installing the Antenna

Unscrew the nuts and washers in the SMA connector.

Insert the SMA connector into the holes provided in the enclosure. See the image above.

Then tighten the nut along with the washers.

Now install the antenna by properly aligning with the SMA connector.

Step 13: Installing the Circuit Board

Mount the standoffs at 4 corners of the circuit board.

Apply super glue at the 4 slots in the enclosure. Refer to the above picture.

Then align the standoff with the 4 slots and place it. leave some to dry it out.

Step 14: Close the Front Cover

After printing the front cover, it may be not perfectly fit to the main enclosure body.If it is the case, just sand it at the sides by using a sand paper.

Slide the front cover in to the slots in the main body.

To secure it, use duct tape at the bottom.

Step 15: Programming

To use Wemos D1 with the Arduino library, you'll have to use the Arduino IDE with ESP8266 board support. If you haven't already done that yet, you can easily install ESP8266 Board support to your Arduino IDE by following this tutorial by Sparkfun.

Following settings are preferable :

PU Frequency:
80MHz 160MHz

Flash Size: 4M (3M SPIFFS) – 3M File system size 4M (1M SPIFFS) – 1M File system size

Upload Speed: 921600 bps

Arduino Code for Blynk App :

Sleep Mode :

The ESP8266 is a pretty power hungry device. If you want your project to run off a battery for more than a few hours, you have two options:

1. Get a huge battery

2. Cleverly put the Thing to sleep.

The best choice is the second option. Before using the deep sleep feature, Wemos D0 pin must be connected to the Reset pin.

Credit: This was suggested by one of the Instructables user " tim Rowledge ".

More Power Saving Option :

The Wemos D1 Mini has a small LED that lights when the board is powered. It consumes a lot of power. So just pull that LED off the board with a pair of pliers. It will drastically drop the sleep current down.

Now the device can run for a long time with a single Li-Ion battery.

#define BLYNK_PRINT Serial    // Comment this out to disable prints and save space<br>#include < ESP8266WiFi.h>
#include  <BlynkSimpleEsp8266.h ></p><p>
#include "Seeed_BME280.h"
#include < Wire.h>
BME280 bme280;
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "3df5f636c7dc464a457a32e382c4796xx";// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "SSID";
char pass[] = "PASS WORD";
void setup()
{
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
  Serial.begin(9600);
  if(!bme280.init()){
  Serial.println("Device error!");
  }
}

void loop()
{
  Blynk.run();

  //get and print temperatures
  float temp = bme280.getTemperature();
  Serial.print("Temp: ");
  Serial.print(temp);
  Serial.println("C");//The unit for  Celsius because original arduino don't support speical symbols
  Blynk.virtualWrite(0, temp); // virtual pin 0
  Blynk.virtualWrite(4, temp); // virtual pin 4
  //get and print atmospheric pressure data
  float pressure = bme280.getPressure(); // pressure in Pa
  float p = pressure/100.0 ; // pressure in hPa
  Serial.print("Pressure: ");
  Serial.print(p);
  Serial.println("hPa");
  Blynk.virtualWrite(1, p); // virtual pin 1
  //get and print altitude data
  float altitude = bme280.calcAltitude(pressure);
  Serial.print("Altitude: ");
  Serial.print(altitude);
  Serial.println("m");
  Blynk.virtualWrite(2, altitude); // virtual pin 2  //get and print humidity data
  float humidity = bme280.getHumidity();
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.println("%");
  Blynk.virtualWrite(3, humidity); // virtual pin 3
  ESP.deepSleep(5 * 60 * 1000000); // deepSleep time is defined in microseconds.
}

Solar_Powered_Weather_Station.ino
Download

Step 16: Install Blynk App and Library

Blynk is an app that allows full control over Arduino, Rasberry, Intel Edison, and much more hardware. It is compatible with both Android and iPhone.Right now the Blynk app is available free of cost.

You can download the app from the following link

1. For Android

2. For Iphone

After downloading the app, installed it on your smartphone.

Then you have to import the library on to your Arduino IDE.

Download the Library

When you run the app for the first time, you need to sign in – to enter an email address and password. Click the “+” at the top-right of the display to create a new project. Then name it.

Select the target hardware " ESP8266 "Then click “E-mail” to send that auth token to yourself – you will need it in the code