Arduino Weather Station.




Introduction: Arduino Weather Station.

About: I’m a Programmer with a interest in Electronics and Cars

A while ago I got a idea to build my own weather station, from scratch.
It turned out great. Lets begin!

Step 1: Parts

A list of items I used:
-2x Arduino nano.
-433mhz transmitter .
-433mhz Receiver.
-4x20 LCD (blue)
-a Blue led and resistor
-Electric installation box (watertight).
- Digital Barometric Pressure and Temp Sensor.
- DHT11 Temperature & Humidity Sensor
-1mm Aluminum sheet.
-PIR sensor (movement).
-Bits of wire.
-Heat shrink tube.
-Nuts and bolts.

And a range of different (basic) tools.

Step 2: Code for Transmitter

So the first thing is to know which port is which on every part of te Transmitter:

The Arduino Nano was simple, just take a look on the site of Arduino.

Next up is the 433Mhz Transmitter.
On the Board it says:

Next. The DHT11. same as the Transmitter
This part uses the 'DHT11 library' 

A Simple LED and Resistor
I used this only if there was something sent.

The Digital Barometric Pressure sensor is another story dhow,
its got 6 Connections
-VCC (3.3v)
-SDA (Serial Data Signal) (I²C)
-SCL (Serial CLock) (I²C)
-XCLR (no idea) (did not use)
-EOC (end of conversion) (did not use)
-GND (Ground)

So we need to use the I²C on de Sensor to communicate with the Arduino.

i uses the next Libs:

Much of the code to read out the Digital Barometric Pressure and Temp Sensor was ripped form various sites/forums.

For Code and explanation, See the Code file


I forgot something you need to do in order to compile the Arduino code.
In order to convert a float to a string you’ll need to download 2 files and replace some file with these in the Arduino IDE.

Download & info:


Step 3: Electrical Diagram Transmitter

Based on the Code I wrote a drew an electrical diagram.
Please note that the Transmitter and humidity sensor works of the 5v line,
the Barometric sensors only needs a 1.8V - 3.6V input.

Step 4: Code for Receiver.

In this code I needed to get the data from me Receiver and decode it to something useful

Screen (hd44780 capable).
-(16 Pins) data and power

PIR (motion sensor).

-Data out

For the Screen I uses the standard Connection.
Only used 6 pins for Data, 1 to 5V and 3 to ground.

The Led +pin was connected to a Arduino Digital Pin.
that way I can control the Backlight whit the PIR.

Uses the next Libs:
-VirtualWire  (for the Reviser)
- string
-LiquidCrystal (for the display)

For Code and explanation, See the Code file

Step 5: Electrical Diagram Receiver

Based on the Code I wrote a drew an electrical diagram.

its recommended to connect pin 3 (V0) of the LCD to a 10K ohm Potentiometer, this Pot meter to VCC and GND.
To control the Brightness.
I connected strait to GND to get maximum Brightness, this works well on a couple of LCD, so TRY it first.

The rest is fairly straight forward.

Step 6: Prototype

The next logical step is to make a prototype of the drawings and testing it.
So I got myself a couple of Breadboard and wire and began building it.

(note1) this picture was taken after I created the code :)
(note2) on the first picture you can see a component that later would be replaced by another part.

Step 7: Designing the Receiver Housing. (first Attempt)

At first i wanted to 3D print a housing,

I measure all the components and wrote them down.
next I put them together in Inventor and drew a housing around the parts.
This ensured that the sizes where correct the parts would fit together

I used Inventor 2014 and Blender to create and render the image

because I did not own a 3D printer a had to send it to ShapeWays, it was to expensive for this project.
So redraw it for a sheet. (see next step)

Step 8: Designing and Buidling the Receiver Housing. (second Attempt)

Here I did the same as in the previews Step,
only difference is that I used Sheet metal drawing instead of extruding.

After this was done, it was a simple job to cut it out and bend it 90 disgrace.
To lock it in place I used 2 aluminum rivets.

(note)Dimensions in mm

Step 9: Painting the Receiver Housing

The next stap is to make the housing a bit more nicer.
So i want to give it a lik of paint.

it had to be a hard paint, able to withstand abuse.

I used "Motorcoater", its designed to be uses on engines.
it resists Olli, grease and lots of stuff, and its scratch resisted :)

A bit overdone, but I had it lying around.

Step 10: Buidling the Transmitter

I chose Electric installation box (watertight), is sturdy and watertight.
perfect for outside use.

I used 2 socket’s to create holes to the outside of the box.
And on those I glued the sensors.

Drilled 3 hose,
1 for Power (5V)
1 for the external antenna.
and  1 for the blue LED

I just coiled some wire for the internal antenna.
Don’t know the best antenna for 433Mhz, but it works.

Step 11: Final Product

And the end result:

A good working Weather station.
Showing Temperature in C, Humidity an barometric pressure .

And all of this in a nice case, and low power consumption

Step 12: Update 1: New Part

A week ago I order a new part for the weather station.
A rain detector, with an Analog and Digital output.
Not sure how to fit this to my Transmitter unit.
Because of the relatively easy way of communication between the units,
it easy to add new components.
Connect a sensor to an open input port, Read out the value, and send it to the receiver.

The Receiver only needs to spit de code and display it at the right line.

I only need to fine tune the sensor to the right amount of rain drops.
or (“No rain”, “ light Rain”, “Heavy Rain”).
So some testing is required.

keep you informed.

Step 13: Update 2: Mesh & Water

I added some Plastic mash to protest the sensors against spiders and other small insects,
this way the cant touch the sensor of get inside it.

And after a couple of rainy days the outside unit still works :)

Ignore the way I attached  the unit to the drain. (duct tape FTW)

Arduino Contest

Participated in the
Arduino Contest

1 Person Made This Project!


  • Science Fair Challenge

    Science Fair Challenge
  • Make It Modular: Student Design Challenge

    Make It Modular: Student Design Challenge
  • Woodworking Contest

    Woodworking Contest



4 years ago

Can someone provide the code for taking intensity with the raindrop sensor


6 years ago

Nice instructable, also first person I have ever met with the same name as me


6 years ago


Is it possible to add a wind speed and direction component to this build?

Great idea, I like how you have built the lcd case looks good and simple.

Both of the Transmitter, and Receiver codes has tons of error and won't verify, did I download the right files?


Reply 7 years ago on Introduction

Hi Partck,

have you installed the libraries for the LCD and the DHT?


Reply 7 years ago on Introduction

I did install a couple different DHT11 and LCD, It work for the receiver however the transmitter still didn't compile. Where did you get your DHT library


Reply 6 years ago on Introduction

Same here with the transmitter, lots of DHT11 errors


7 years ago on Introduction

Hi! great project, I made everything but I can't compile TX because I cant find wich DHT11 library are you use. Could you give us a little help ? 10x


7 years ago on Introduction

Hi Bram,

I made a similar weather station but I have a problem in the RF communication. It works properly at the beginning but after a while I lose some chars from the end of the message.

If I monitor the message through the serial monitor of my UNO before sending it, the message is OK. The received message is OK also at the beginning but after a certain time I loss some chars from the end of the message. I have to reset the UNO which receives the message to repair the communication.

Have you ever encountered with this problem? Have you any suggestion to solve it?

THX Gyalu


Reply 7 years ago on Introduction

I found the problem and could solve but I don't understand the cause...

I moved this two lines from the top of my program into the loop()
byte messageLength = VW_MAX_MESSAGE_LEN;
byte message[VW_MAX_MESSAGE_LEN];
after that my radio worked well.

Since this variables are local its all right.


7 years ago on Introduction

I'm just buying the material to build something like that. Nice to have found that as I'm newbie to Arduino and C. I had in mind to also show the min and max temp with a button to reset these max and min as we have in external thermometer. Would it be a though job to modify the code to get that ? Thanks


7 years ago on Introduction

would your Tx and Rx codes work if i were to use Arduino Uno boards instead of the Nano??


Reply 7 years ago on Introduction

Hi, Yes i think so, the pins are basically the same between the Uno and Nano,


7 years ago on Step 12

if i can make a suggestion..... the rain sensor now has two 90degree-angled pins sticking out at the top. De-solder them and either take straight pins coming out of the bottom or just 2 wires coming out of the bottom.
That way you only need a very small hole to put them through. When the rainsensor is then flush, lay a small wall of silicone against the rim to stop any water from leaking under it.
With regard to its analog output... I wonder if that is any added value because that is already what you get when just using it as a voltage divider with another resistor. So if you want to use it in analogue mode, no use the add the little sensor board it came with and feed a comparator IC that is just idle: just grab a resistor and use it as a voltage divider


7 years ago on Step 8

Weet zeker dat je niet 'disgrace' bedoelt maar 'degrees' :-)
'disgrace' is weer totaal iets anders


8 years ago on Introduction


Great Instructable, I am going to make something similar.

Quick question, is your power from the mains or battery?

Thanks for taking the time to share the code!


Reply 8 years ago on Introduction


Both the sender and receiver are powered by 12v power adapters from mains.

The idea was to power the outdoor unit from a Lipo battery charged by solar panels, but i chose the easy way.
Maybe i'll build this in the future


8 years ago on Step 4

HI Bram,
Like your neat Weerstation, wil en copie marken
Can you post the latest code for your Weerstation.



Reply 8 years ago on Step 4

Hey Peter,

The Code in the Zip above is the latest code.
I wanted to write new code, but i didn't had the time for it.