“This post isn’t another How-To tutorial for a specific sensor because the Arduino community has already produced a considerable number of resources like that. You’d be hard pressed to find any sensor in the DIY market that doesn’t give you a dozen cookbook recipes to follow after a simple Google search. In fact, you get so many results from “How to use SensorX with Arduino” that beginners are overwhelmed because few of those tutorials help people decide which type of sensor suits their skill level. This post attempts to put the range of different options you can use with a Cave Pearl data logger into a conceptual framework, with links to examples that illustrate the ideas in text.
One thing to note before you start is that many modern sensors will only accept 3.3v inputs, so UNO based projects need to check if the sensor they want to use is 5v tolerant. Most sensors from vendors like Adafruit put regulators on their breakout boards to handle this 3.3v-5v translation, but you may have to place level shifters between some of the more advanced digital sensors and an UNO based logger. Occasionally you run into the opposite situation where the sensor requires 5v (or more) forcing Pro Mini based systems to do the same thing.”