For me its the ‘Knock Code’ that LG had on their phones (I really wish LG still made at least the V series phones)
Basically there was a four-square area and you set up a sequence of where you would tap to unlock the phone. That set of squares was only shown when you set up the code
Then, to unlock your phone, you would tap those areas in the sequence you set up (even with the screen off).
Fingerprint readers are nice, but I really do miss the knock code
Edit: did find this article with a way to do the knock code, but if done wrong, could brick your phone I guess.
Plus, article is from 2014. When I looked at XDA’s info on it (they also being the developers) it looks like development on it is over, but individual modules may or may not still be supported by their devs
IR Blasters!
I feel like I’m the only one who used them or cares that they were quietly phased out of phones.
You used to be able to use your phone as a universal remote. Being able to control my TV, sound system, ceiling fan, and lights all from my phone was so convenient! Plus if you were stuck in like a waiting room and they had ads or garbage like Fox News on, you could change the channel or turn it off completely. It was an incredibly useful feature to me, but I guess barely anyone else used since it was removed from phones without any complaints.
Except me. I’m complaining!
Back in the day, I discovered I could i) print over IR to our office’s HP laser printer from my Psion organiser, ii) print control codes from the built-in OPL language to change the display message on the printer. I would occassionaly send messages like “insert coin”, “too much paper”, “grammatical error”, etc. when colleagues were printing.
I love it! Those messages are hilarious!
Wing night at the pub took on a whole new danger. The IR blaster was a total selling point for me on a few devices.
Still had one on my previous phone - LG V20. Loved when people starter looking around confused when I started browsing the channels on the public TV on gas stations, waiting rooms, gym etc.
I really miss it too. My wife loses the remote every 5 minutes.
Redmi Note phones still have (or at least had) them.
I remember transferring files via IR. It was convenient.
I remember, pre-Wifi, setting up a network over IR between two laptops to play C&C Red Alert.
Infrared Alert