If you want to talk to your grandmother on messaging app Telegram and she doesn't have a smartphone, she'll need to get one. She'll need to learn how to use iOS or Android. How to manage notifications. You could teach her all of that -- or you could just build her a 1900s telephone switchboard that does nothing but send and receive Telegram messages.
That's what Twitter user and inventive grandson @mrcatacroquer did for his yaya (which means "granny" in Castilian), creating a charmingly tactile device he calls the Yayagram. The Telegram-connected switchboard is wonderfully simple to use. All Yaya needs to do is link an analog jack connector between her name and the person she wants to message. Then she speaks into a microphone, and the audio is sent as a Telegram message. When Yaya gets a reply, it's printed out on a sheet of thermal paper.
The entire project runs on a Raspberry Pi 4 computer and a Python script for sending and receiving messages. Mrcatacroquer says hearing problems make it hard for his yaya to use a phone, so he built the Yayagram to make it easier for her to talk with family during the pandemic.
For now, the Yayagram is just something fun Mrcatacroquer made for his own family, but he plans to make an Instructables guide to help others build their own.
See also: 25 fun things to do with a Raspberry Pi