Tell HN: I have an idea of a smartphone application

Please help me to develop my favorite idea. This is a calendar for the Nature. I did not think about the source of information but I want to open the app and to observe what regular events are coming right now. After enough research it will be dozens of that events per day.

Please help me to define a stack of technologies and minimal possible budget assuming I have the data and knowledge of few programming languages but do not have any database and hosting biases.