On a normal TV remote, entering a number changes the channel to that number. But on this one it mutes the audio for that number of minutes, then automatically brings it back. It uses a standard 4x3 keypad, and a modified 3.3V 8MHz Arduino Pro Mini.
Nice project! Maybe it's just me but none of the 'links' at the bottom of the .pdf description work. They're just blue underlined text. I tried holding down <ctrl> on a hyperlink, like one does in the Arduino IDE, and that didn't help either.
I had the last three links in bold, which I've now corrected. But all of the links are valid hyperlinks, and work as such in my Foxit reader if I download the "raw" file from Github. But if I just click on the pfd on Github, it displays the pdf, but the links don't work. So you might try the raw download, or just download the entire repo as a zip.
Edit: If I do the raw download into Firefox, Firefox does not show them as hyperlinks, but if I save the file from Firefox and load it back into Foxit, they all work. So apparently they don't work in Firefox at all. I don't know if there's anything I can do to make this work.
I found an online rtf to pdf converter, and the links now show up at least in Firefox. Still not if viewed on Github, but that may be deliberate on Github's part. Anyway, try downloading the raw pdf again and see if it works better for you.
My code assumes the default state is unmuted. But all it actually does is toggle the Mute button. So if you start muted, then it should work as is, and the time you enter would be the unmuted time.