Arduino is an open source hardware project which means anyone can build and sell boards based off of the Arduino design. This is good because other manufacturers can sell boards for a fraction of the cost of a genuine Arduino board, but the downside is that quality assurance on cheaper boards can be lacking.
There are numerous type of Arduino Boards. You basically code for them the same way, but different boards offer different options such as more Digital Connections, or WiFi.
You can use Analog Pins on your Arduino Board to read from an IR sensor if you need a numeric reading. Functional Parts in the Project: Arduino Uno – https://store.arduino.cc/usa/arduino-uno-rev3 IR Sensor – https://amzn.to/2IDw7SE