From some yearsago until now, we are living the digital transformation. One of the pillars of this digital transformation is the revolution of the smartphones. At the beginning, the mobile phone was intended for communication between people, but now, we use it for many other things. Pay for our purchases, post on our social networks, listen to music, maintain contact between companies and their customers, read the news, and so forth.The jump from conventional mobile phones to smartphones came accompanied by mobile OS. This is in charge to control all the programs and functions of the mobile. One of the most important OS and on which the application described in this document has been programmed, is Android.The mobile market is dominated by this OS for many years, having only one strong competitor, iOS. Some of the strengths of Android versus iOS: Android is intended in open source code. This means that all of us can contribute to the development ofthe code. The knowledges about Android are shared in the net for all who want to develop an android app.Android is incorporated in almost all phone brands in the market, meanwhile iOS is only incorporated in apple devices.The prices of the devices of both OS are quite different. The cheapest iOS devices are around 500-600€ while the cheapest android devices are around 200€.These reasons make Android the strongest mobile OS of the market, and the future forecast is that it continues... On the other hand, android is gaining so much recognition due to some factors as the growth of the developer community, currently there are more than 3.800.000 applications in the Google Play Store. To develop an android app is an easy way to earn money so many people is trying their luck. Other reason is the digital transformation of companies. Nowadays having an application is synonymous with staying alive in the competitive mobile market. The customers want the possibility of doing the same as they would do in the establishments of the companies from home. The way to get this is through the applications.Knowing all I have said, I would want to develop my own android app and I see the opportunity in this project. I could reach many people through android. By doing a research, I came to the conclusion of developing a health-related application, and in this way, I could learn a new programming language and at the same time help people. The purpose of the application is to research if it is possible to automatically measure the breathing frequency using only a mobile phone. In addition, I decided to develop a completely functional app for publish it in the Google Play Store.Before start to program, I had to learn the Android basics through internet tutorials, and then Icould start the development. The first step was a brainstorm, in order to imagine a first version of the application. I drew in a paper all the user interfaces of the views and wrote all the functionality that I wanted to include. Of course, during the development this first version was changing until get the current application.The next step was starting to develop the application. Then I am going to resume all the views and their functionalities. In total it consists in sixteen views with different functionality each one of them.