As of late, most of us are lucky sufficient to make use of smartphones with respectable touchscreen keyboard capabilities. Nonetheless, as soon as upon a time, when you wished to sort one thing on a telephone, you needed to faucet it out on the quantity keys as an alternative. [Jarrett] is bringing that again with a customized T9 keyboard for contemporary telephones.
The construct is designed across the keypad of the Nokia E52, a Symbian smartphone launched in 2009—two years after Apple modified the sport with the primary iPhone. The telephone keypad itself is laid over a customized PCB with Alps SKRK tactile switches corresponding to every particular person key. Every is wired with a diode and the switches are scanned as a row/column array as is typical for keyboards. Studying the matrix is an ESP32-C6 microcontroller, which counts the keypresses and spits out the best letters over its Bluetooth connection to an hooked up smartphone or different machine. Energy is through a small lithium-ion battery, sorted by a TP4200 charger chip.
General, the keyboard works as you’d count on, permitting T9-style enter to any appropriate machine that works with Bluetooth keyboards. [Jarrett] does have one remorse, with the 0.98 N actuation power switches used leaving he keypad feeling slightly mushy. The firmer 1.57 N switches have been suspected to present a extra satisfying response underneath thumb, which was a pleasant improve within the second revision construct.
We’ve seen different builds on this vein earlier than, too, albeit with larger keys. When you’re arising with your personal esoteric enter strategies, don’t hesitate to notify the tipsline.
