Condensation Risk Evaluator

Hi everyone, I work as a builder even though I've been always really interested in new technologies.

I've learned a little about 3d printing, Arduino and electronic issues reading a lot. I visit this web regularly so I would like to make my little contribution.

In my job sometimes it is not so easy to know the reason of the moisture in a wall which causes unhealthy environments.

This project will help us to distinguish between a water leak and a condensed moisture.

To achieve it, I had the idea to monitor with a data logger the following values over a period of time :

-Environmental humidity

-Ambient temperature

-Temperature of the wet area

Those values allow us to realise if the temperature of the wet zone has been under the dew point. That means that the condensation is the cause of the humidity.

Although a termographic camera would make this work, there are two reasons why I have made this project:

1.-They are very expensive

2.-the moment of the measurement could not be the right one to get the datas due to the changes of the values over the day.

I hope this project could help someone.

Step 1: Bill of Material

-arduino nano data logger
https://s.click.aliexpress.com/e/0vsomLQ
-arduino nano v3 (clon)
https://s.click.aliexpress.com/e/tWzq3o4
-OLED display 0,96 ssd1306
https://s.click.aliexpress.com/e/0vsomLQ
-Humidity and temperature sensor DHT22
https://s.click.aliexpress.com/e/bPMNuPhI
-Infra red Temperature sensor Mlx90614
https://s.click.aliexpress.com/e/bY57Pd1I
-2 batteries 18650 3500mah
https://s.click.aliexpress.com/e/b1uwHSV6
-case for 2 batteries
https://s.click.aliexpress.com/e/b2qTzSrQ
-some wire ,tin welding y PLA filament
Total acount less than 30€

Step 2: Where Can We Put Everything ??

After getting the code which worked properly, I should confront this problem.

I needed a box to place all the components. I wanted not only to keep everything together but also that the MLX90614 could move to point the target.

To get it, I designed this case with Autocad2015 and I printed it with my 3d printer (Anet A10). As everything in my project, this could be better but maybe it can help someone.

Here you have the stl files.

I apologize for any possible mistakes but it is my first project.

Thank you for your time. If you need any further information, please, do not hesitate to contact me.

If you find it interesting, I would appreciate your vote or at least a like. ;)

Step 3: Let's Connect Everything

Well, now we have all the necessary.

We start out with an advantage. The data logger has already connected a micro sd a RTC clock.

As I'm not an expert, I've begun watching tutorials and collecting further information about the sensors.

I needed to connect DHT22, MLX90614 and also the OLED display.

To connect each one separately is quite easy and there are several tutorials for doing it, but the most difficult was that everything works together.

I leave the Fritzzing squematic with the connections wth the separated modules in case someone has not access to the Arduino nano data logger.

Also, I have included a voltmeter (voltage divider) to know the battery status.

Step 4: The Code

The code is that has taken me the longest time and it still has any little problems (I would really appreciate if someone could check it , lol ) but it fulfills its purpose.

As I have some limitations in terms of programing, my way of dealing with it has been to gather examples that I have found in different libraries.

The most difficult was to find the libraries for the OLED display and the MLX90614, each one worked separately but all together was impossible to make them work. I attribute that to the fact that OLED, MLX90614 and Micro sd, the three of them, they use I2C.

I tried it with a LCD 16x2 display and it was easier but I wanted to do it with the OLED display.

Finally I managed to make it work though that took me lot of hours of steps forward and steps back.

The sketch works as follows:

-Libraries are included.

-Variables are defined.

-Sensors are initialized.

-Dew point is calculated and it is compared with the temperature of the wet zone keeping it in a variable called Rcond (condensation risk).

- The datas that are saved in a micro sd card are: Environmental humidity, wall temperature, Rcond and Rmax (max value of the Rcond variable) and also the date and the time.

-The relative humidity, the temperature of the wall, the Rmax and the voltmeter value are showed on the screen.

-The sketch is configurated to go to sleep and each five minutes to wake up and get the values. This can be configurated. With this configuration the batteries life is up to seven days. This time is enough to get significantly datas.

- The datas are saved in a text file that can be easily imported in an excel file and to create graphics to value if the humidity reason is the condensation.