Yes, I am the first one (nice, Jolla slogan used!) to open a thread about building an OtherHalf with a qwerty slider! In this thread I will post my ideas, pictures and ask questions to you guys. The goal -for now- is to have a complete setup ready for when the first batches of Jolla phones is shipped. The qwerty slider is without a doubt the most anticipated extra feature and with some extra time on the hand, why not!? http://i.imgur.com/jMYGijl.jpg So, lets dive right in! The Jolla phone will have a I2C connector on the back. Luckily, my RPi has I2C as well, so the first prototypes and proof-of-concepts can be tested. The RPi and Sailfish both support Python, which makes the programming a lot easier. I don't have any experience with the Sailfish SDK, but that will come later on. The keyboard itself will be taken from my old -and dead- N900. Nostalgia much?! The keyboard consists of the motherboard with the electrical connections, a plastic sticker with pieces of metal to make the connection and the *click*, and the actual buttons. http://s2.postimg.org/cv4qdzz95/13100005.jpg The motherboard will be scrapped. To complicate things, I will try to build my own pcb from scratch. This tutorial provides all the necessary steps. It will be a double-sided board. On this pcb, there will be a button-matrix similar to the one on the motherboard. To connect the keys to the phone, a mcp23017 i2c gpio port expander will be used. Next step, pcb design. The N900 keyboard had some issues with NKRO, perhaps someone can shed some light on this to design a new way to connect the keys in a better way? The gpio-expander had 16 i/o ports. The software: the keyboard has to be continuously scanned for key-presses. How will a background python (or other) script affect cpu and battery usage? Better/possible to start/stop the script when the keyboard is slided out? Continuously scan for I2C devices? For the near future, testing software will be on the RPi. I have some experience with that, but help is welcome. The slider mechanism: Maybe the old slider mechanism from the n900? Design a new one? Other options? Personally, if parts are machined nice, I love to show mechanical parts. If not, the game is to not show anything. http://phandroid.s3.amazonaws.com/wp...en-550x412.jpg Please keep the topic clean and respond if you would like to (and can) help!