DIY Weather Station With Bluetooth

by Matej Blagšič

58K47118

Intro: DIY Weather Station With Bluetooth

Hello everybody.

Recently I attended a course in our University of Electrical Engineering and we were making ourselves a small weather station. It included learning about soldering, sensors and arduino. It was super fun making it with little kids and other high school kids my age. I will show you how you can build it yourself, what components do you need and explain you the code and how can you upgrade it with more sensors.

STEP 1: PARTS

To do this project, you will need these items:

Seeeduino v4.0 or Arduino Uno

BMP180 temperature and pressure sensor

DHT22 temperature and humidity sensor

HC-06 bluetooth module

Project case / outdoor case

STEP 2: Why Seeeduino V4

The main question is why did I/we choose the Seeeduino V4. If we were going for a cheap Chinese alternative, we could have gone with Funduinos or anything like that, as the Seeeduino is only a few bucks cheaper. The answer is the features. I see it as an upgrade to the Arduino Uno. It has all the features labeled with arrows. Some are subtle like the micro USB port, as many of us have smart phones that uses the same plug, option for soldering male headers parallel to female ones and the convenience of the already built in ports form I2C and serial data.

The major ones are really blessed by me. The 3.3V - 5V logic switch is priceless because so many arduino peripherals and mostly sensors work with 3.3V. I wasn't aware about this a few years ago, as 5V stood to me as a standard but really a lot of sensors work with 3.3V and the most of 5V ones can operate with that voltage without any problem. Refer to the sensors datasheet for that information.

This board will work on 3.3V great with one of our I2C sensor and the other one that operates with 5V. Also some of the bluetooth modules work with 5V, but the logic works with 3.3V. I will address this topic in the bluetooth step of this tutorial.

STEP 3: BMP180 I2C Temperature and Pressure Sensor

So firstly, we're going to take a look at the first sensor that is BMP180 and it is an I2C type of sensor. It works with 3.3V and NOT 5 as many of the Arduino boards. That means that the voltage supply and the communication lines work with 3.3V. This is one of the reasons why we bough the Seeeduino but more about that in the next few steps.

The whole connection to the main processing board (Arduino/Seeeduino) will be shown after the introduction of the components.

The picture also shows you the pinout of the device, so you will later know how to connect it to the rest of the circuitry later.

STEP 4: DHT22 Temperature and Humidity Sensor

The next sensor is the DHT22 Temperature and Humidity sensor. It works with 5V or 3.3V so it could be used in 2 different scenarios with the Seeeduino board or normal 5V Arduino Uno. The pinout is explained in the picture, but you can see, that it operates in a different way. Instead of using let's say I2C, analog output it uses digital output. For that we will need a library, that will grab the data from the sensor at the correct times and transform it to usable numbers. I will link to adafruit library for this sensor.

One thing to note is that this sensor is quite precise therefore it measures data every 2 seconds. This will be dealt with in the code, as we will be updating data every 5 seconds or less, as the ambient temperature doesn't change as fast.

STEP 5: The Schematic for Working With Seeeduino or Any 3.3V Operating Board

The picture shows all the connection with the sensors to the Seeeduino board. The board is V3, but just imagine that the logic switch is turned on the 3.3V. Everything connects pretty simple. BMP180 connects to the supply and the SCL to A5 and SDA to A4. DHT22 needs a pull up resistor between Vcc and data pin. Than you connect that data pin to any of the digital pins on the Seeeduino. I chose pin 2.

The code for the sensors is in down available to download. It collects data and puts in on the Serial line as you can watch it on the Serial monitor or via an Android app. The app is described in the one of the next steps.

STEP 6: How to Wire the Componets on a 5V Microcontroler Board

Now comes the picture as how to connect everything together on a 5V only board. The board can however supply 3.3V like Arduino Uno but the logic level is at 5V.

To do this, we are going to need level shifter/converter like this one, I bought on ebay (http://www.ebay.co.uk/itm/400953346213?_trksid=p2057872.m2749.l2649&var=670492331993&ssPageName=STRK%3AMEBIDX%3AIT)

They often address them as I2C logic switcher but that's mainly because that's the most often purpouse. However, you can only use it for small loads, as for say communication lines and not to regulate 5v to 3.3v, as it isn't designed for that.

The picture may be confusing but hold with me.

-The supply voltage for the components is 3.3V that the Uno can output

-all the communication lines including TX/RX, SCA/SCL and dataPin 2 are connected to level conveter on the LV(low voltage) part and are connected from the HV side of the converter to the Uno --> so everything like before with the level switcher in between.

Now you might be asking yourself why did I put the bluetooth module and the 5v sensor to the logic switcher as well.
I did it to simplify everything and as the lowers amount of channels of the level shifter that you can buy is around 6 or something. Anyway, you can connect the 5V sensor directly to 5V separately and the data line directly to the Uno digital pin.


THIS IS IMPORTANT

I had a bluetooth module that operated on 5V on Vcc and logic. But a lot of them have markings that it poerates on 3.6-6V on supply, but with a text "level:3.3V" .

The picture shows the back of it, so it's good to connect it all to the Vcc and it worked fine with me. If the range decreases because the Vcc is connected to 3.3V and not the minimum 3.6, you can allway connect Vcc to 5V and the logic will work on 3.3V.

STEP 7: The Code

At the bottom is the code that you can download. It's output should look like on the picture. The code also has variables at the beginning of it to calibrate the sensor if any offset is recorded. Note that sensors accuracy can vary at a different range. DHT22 for example is an upgrade to DHT11 with better accuracy thru out the range

Here are also the links to the libraries for both sensors: Just click "Download Zip" and extract it into your libraries folder

BMP180

DHT22


DHT library is universal for all DHT type sensors, and you define the version in the code.

I almost forgot the app. It's called Bluetooth terminal and it's great as the whole screen is dedicated to showing serial data and sending it on the bottom. The picture shows the app on Google play and the inside of the app.

STEP 8: Conclusion

Thank you for watching my instructable. I hope that you make it work and if you have any question about the project and something is not working, be sure to leave a comment below or on private message.

If anyone is interested how I put it all in the case, make sure you leave a comment on that one :)

I will do it with ESP8266 module in the future, as my instructable about it is quite popular, so look for that one soon.

ESP8266 tutorial

18 Comments

azrifahmy 5 years ago

Hello,my name azri. I'm trying to make this project.Unfortunately when upload codes in arduino ide it states that:

exit status 1
Error compiling for board Arduino/Genuino Uno.

I have already add the libraries and download the weather statation.ino accordingly.Please help me solved this problem.Thank you very much.

AaravM 6 years ago

also which pin on the arduino connects to the scl and which connects to the sda

Regis35 7 years ago

But arduino uno is having a 3.3 volt output

mrizvic 8 years ago

Hi Matej,

if you replace HC-06 with ESP8266 module you can easily connect your weather station to the internet using https://github.com/mrizvic/nodemcu-uart2http-exosi...

Code modification should be minimal. All you need is ESP8266 and exosite.com account :)

Any feedback on this is appretiated!

Best regards,

Marko Rizvič

Matej Blagšič 8 years ago

Hello (Zdravo :) )

I will try to do this as it sounds amazing and I can see that you added some files for the esp8266. I logged into exosite.com, but I can see that you have to pay monthly or yearly and it's not cheap as for any diy guy that wants to do this project. I did another instructable on ethernet shield and sending email done by using service temboo.com that did all the code, libraries that are actually included in Arduino IDE and does email sending part. I might try there, but thanx for recommendation.

mrizvic 8 years ago

Hm i'm using exosite for free but i'm limited on using two dashboards. I'm not sure about number of devices because i'm using only one. Anyway there are plenty of freemium services that offer data visualisation and my code can be easily adapted to them. If you find anything interested let me know. I will see how much effort does it take to make modifications for adaption :)

JeremyH20 8 years ago

Honestly, If I were you two and were looking for a good place to do what you are looking to do; I would try to see if you could use the Beta of Adafruit.IO. It seems really great and should fit this purpose nicely.

CatalinRO 8 years ago

I used this cheap Chinese version of Arduino Uno (Buono Uno R3): has switch for 3V3 - 5V logic, is compatible with Arduino shields, is working on Arduino IDE, has micro USB, has power connector separately, it costs 10 USD. On logistics, it took the same amount of time to arrive like the delivery from SeeedsStudio. (search ebay for Buono Uno R3) http://www.ebay.com/itm/BUONO-UNO-R3-Compatible-Arduino-R3-3-3V-5V-Selectable-version-2A-cable-/221601022675?hash=item33987342d3

Matej Blagšič 8 years ago

It looks nice. I'm glad you pointed it out, but Seeeduino was the available at the time as the University already bought 15 pieces for all of the children and I never stated it was the cheapest.

CatalinRO 8 years ago

I looked for a 3V3 Arduino and found this alternative (check uber home automation project from Instructables). It is good that you did not have to pay for that Arduino like board :)

Dochol54 8 years ago

Where would I find these components? I haven't a clue. Thanks

mikestudent 8 years ago

Also Hobbyking for the bluetooth module and the bmp180

Matej Blagšič 8 years ago

Look on ebay, if you want the cheapest, you got some links in other comments or you can also use sparkfun or adafruit

stephenf 8 years ago

Interesting.

Thinking of setting up in a protected (shaded) corner of my yard.

Any ideas on powering this via solar cells?

Matej Blagšič 8 years ago

You can use a Pb battery and a battery charger. You don't need a lot of power.

I will notify you with the current draw of the whole unit or somebody can provide that information if you already know it.

Volthaus Electronics Laboratory 8 years ago

This looks really interesting. I really like working with remote weather sensors. I have mostly been working with 433MHz modules but am starting to with the Bluetooth as well. I just like the longer transmission with the 433MHz. But Bluetooth is great for inside the house. Thanks.