Can I use my Android device as remote control for my SmartTV? As a similar question was deleted by its owner while I wrote up the answer, I decided to share it this way.

I have a Samsung SmartTV, and want to use my Android device to remote-control it – including switching TV channels, adjusting volume and, if possible, the full spectrum of features the SmartTV offers. My Android device does not have an IR blaster, and I'm not speaking of "buying additional hardware" for it.

Is this possible – and if so, how?
There are multiple possibilities to remote-control your Samsung TV with your Android device. For one, there are a bunch of Samsung TV remote control apps giving you a wide range of choices.

A second variant would involve FHEM on your PC (this is a home automation software, and there's a module available for Samsung TVs – I use this, so I can vouch for it) and, optionally, the andFHEM Android app. This way you cannot only use your Android device, but any device with a web browser to remote control the TV – and even integrate it with some other (home) automation stuff. For example, using tasker you could have your TV turned off (or mute it) whenever you receive a call on your Android device – or turn it on as soon as your device connects to your local WiFi. Much more is possible, of course :)