Hi all! this is my first post so hello to everyone ^^
I'm new to sensor interfacing so the first thing I noticed is that some sensors are 5v and some others are 3,3V. I bought some sensors on gearbest and some of them doesn't have a datasheet and I can't find it. for example this sd card reader: http://www.gearbest.com/development-boards/pp_63013.html it has a 3v3 pin, so as far as I can understand all logical inputs must also be 3.3v. but what about this GPS: http://www.gearbest.com/rc-parts/pp_27027.html ? it only say "VCC"; now by experience I know it runs well at 5v but where can I read it? you might say look at the main chip and look for the datasheet. The "problem" is that some of those shields (or "breakouts" as they call them), also have a logic converter and a voltage regulator so they allow 5v and 3.3v. how can I know if I should supply 3.3v or 5v? Is there some sort of standard like VCC means always 5v (logic and power supply) and if instead labeled 3v3 means all logic and power supply must be 3.3v?