In this tutorial, I am going to show you how to build a Solar powered WiFi Weather Station with a Wemos board.The Wemos D1 Mini Pro have small form-factor and 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 Internet Of things ( IoT ) and is Arduino compatible.
The new Weather Station have 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 )
3. The whole circuit along with power supply is put inside a 3D printed enclosure.
4. The range of the device is enhanced by using an 3dBi external antenna .It is around 100 meter.
Full Project is also available on Instructables
Step 1: Parts and Tools Required
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 )
12. Super Glue ( Amazon )
13. Duct Tape ( Amazon )
14. 3D printing filament -PLA ( GearBest )
Tools Used :
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 farm house).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 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 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 to buy a module which have 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 over voltage 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 microcontroller. For simple easy wiring, I will suggest to by I2C version board.
Step 4: Using an External Antenna ( 3dBi )
The Wemos D1 mini Pro board have a 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 Eamesto rotate the zero ohm resistor.
Then snap the antenna SMA connector in to the Wemos Pro mini antenna slot.
Step 5: Solder the Headers
Wemos modules come with variety of headers but you have to solder it according 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 foot print.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 a screw terminals for battery connection.
Step 7: Mount the Charging Board :
Stick a small piece of double sided tap 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 colours 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
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 have 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 design, it is time to 3D print the enclosure. In Fusion 360 you can click on 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.
As I am new to 3D designing, my design was not optimistic.But I am sure, this enclosure can 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 degC
Bed Temp : 55 degCr
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 in to 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 in to 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 in to 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 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 deepsleep 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 consume 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 long time with a single Li Ion battery.
Download the code from Instructables
Step 16: Install Blynk App and Library
Blynk is an app that allows full control over Arduino, Rasberry, Intel Edision and many more hardware. It is compatible for both Android and IPhone.Right now the Blynk app is available with 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 – so 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.
Step 17: Make the Dash Board
The Dashboard is consists of different widgets. To add widgets follow the steps below :
Click “Create” to enter the main Dashboard screen.
Next, press “+” again to get the “Widget Box”
Then drag 4 Gauges.
Click on the graphs,it will pop up a settings menu as shown above.
You have to change the name "Temperature",Select the Virtual Pin V1, then change the range from 0 -50.Similarly do for other parameters.
Finally drag a graph and repeat the same procedure as in gauge settings.The final dashboard picture is shown in the above picture.
You can change the color also by clicking the circle icon on the right side of the Name.
Step 18: Uploading Sensor Data to ThingSpeak
First create an account on ThingSpeak.
Then create a new Channel on your ThingSpeak account. Find How to Create a New Channel
Fill Field 1 as Temperature ,Field 2 as Humidity and Field 3 as pressure.
In your ThingSpeak account select “Channel” and then “My Channel”.
Click on your channel name.
Click on “API Keys” tab and copy the “Write API Key”
Open the Solar_Weather_Station_ThingSpeak code .Then write your SSID and Password.
Replace the “WRITE API ”with the copied “Write API Key”.
Required Library : BME280
Credit : This code is not written by me .I got it from the link given in a YouTube video by plukas.
Download the code from Instructables
Step 19: Final Test
Place the device on sunlight, the red led on TP 4056 charger module will lit up.
1. Blynk App Monitoring:
Open the blynk project.If everything is Ok,you will notice the gauge will live and the graph stat to plot the temperature data.
2. ThingSpeak Monitoring :
First open your Thingspeak Chanel.
Then go to “Private View” tab or “Public View” tab to see the Data Charts.
Thanks for reading my article.
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