Peltier doubts. Drybox project

[PerryBebbington]

I don't know what that is, and as I don't speak Spanish I can't read it, but if it does what you want, or you think it does, then give it a try. It doesn't look like what I had in mind, but hey, if it's what you need then go for it. It does look a bit small.
Here's an example of what I was thinking of:

Blyss WDH-316DB 16Ltr Dehumidifier - Screwfix

The price is higher than I thought though.

Tutorials:

Buttons and other electro-mechanical inputs (introduction)

Intended audience This tutorial is intended for people who have mastered the basics of electronics and C/C++ programming. If you are a beginner and find the concepts difficult, please review the basic examples in the Arduino IDE. In this tutorial BUTTON will be a generic term for any kind of switch or other input device with mechanical contacts. Introduction A common requirement in many projects is to have push buttons, switches or other electro-mechanical devices connected as inputs to an A…

https://docs.arduino.cc/built-in-examples/digital/StateChangeDetection/

There are others. The point is to detect the moment the button is first pressed, NOT that the buttons remains pressed for some time afterwards. This is a common question on here, so some reading of the forum should throw up plenty of examples.