Converting serial signal (12V-5V) and reading it using Arduino - Electrical Engineering Stack Exchange

I'm trying to read some commands from a device that uses non-standard voltage levels for serial communication. It uses 0V for 0 and 12V for 1. For all I know, TTL levels are 0-5V, so if I want to

Power circle“ - first buck then boost for converter testing

Issue with powering relay and several sensors with Arduino

serial - Receiving input from RS232 and reading it with Arduino

Can't get a reading from an industrial sensor - General

mosfet - DC motor and smoked arduino - Electrical Engineering

What are the hardware requirements for connecting two Arduinos so

analogRead() erratic readings through op amp - General Electronics

arduino - Hacking a vacuum fluorescent display from an old DVD

ftdi - Convert FT232RL board from 5V to 3.3V - Electrical