Logic level is the term you are looking for. On older electronics, it was higher because transistor designs were cruder, and you needed higher voltage potential to switch them on/off. As time went on, better chip designs allowed logic voltages to go lower, making for systems requiring lower voltages thus resulting in less waste heat, smaller power systems, etc. These days there are 3 standards; 5v (or TTL) is considered the older standard, and it is rarer and rarer every year for new devices to support it. 3.3v is the bulk of electronics these days, and is the basis for most modern-produced devices. 1.8v is starting to come onto the scene, but usually you'll see chips advertised as "1.8v compatible" when really they can run on 3.3v fine. It depends on the part, but in general chips that can operate at both 3.3v and 5v will output their signals at the voltage level of their power inputs. There are many exceptions to this though. For instance, some chips have a power supply and a logic power supply, allowing you to power the chip from X volts but run the logical communications from 3.3v. Another common one in the hobbyist world is adapter boards. Many breakout boards are more than just the chip itself, but will come with built-in logic level shifting and everything else required. If you're not using parts with these built in, you can also add your own logic-level shifting circuitry. Luckily, there's an even easier fix for you; all of the parts you linked will work fine on 3.3v. Just replace the 5v rail with a 3.3v one (can tap off the regulator on the Teensy), and you're set. More on reddit.com

Where do you live? Country i mean. More on reddit.com

I use both the Nano and the Teensy MCUs including the 3.2, 3.6 and the new 4.0. If you want to start using a Teensy MCU then I would recommend getting the Teensy 3.2. The only drawback going from a Nano to a Teensy MCU is that a Nano will run on a V+ of 5 to 20 volts but a Teensy MCU will only run on a V+ of about 5 volts. If you are using a 12 volt power supply volts then, you will need a voltage buck converter to lower the voltage to 5 volts for the Teensy. Also as you mentioned, I use a level shifter to bring the Teensy’s output voltage of 3.3 to 5.0 volts for use with RGB LEDs. The Teensy MCUs are great boards when you want the extra computing power and larger memory. More on reddit.com

Go with micro. Teensy 2.0 is nice, but has different pinout than all the micros. Teensy 3.2 is also nice, but not as many people use the controller chip so there’s not as much tech support if things go wrong. Also, leds miiiiight work, but I wouldn’t do it. It’ll be expensive and they’ll be blinking constantly (but not in a nice way). They also might not switch fast enough, though I don’t know that. 1n4148 is going to be a thing for the rest of your life, just get a box of 1000 and call it a day. :) More on reddit.com