Soldered Inputronic KEYBOARD

Inputronic Keyboard is a complete 80-key keypad built around TI's TCA8418 I2C keypad scanner. All 80 tactile switches are wired into an 8x10 matrix connected to the chip's row and column pins, so the board handles scanning and debouncing on its own instead of needing 18 GPIO pins on your microcontroller.

It talks over I2C at a fixed address of 0x34, which can't be changed since there's no address-select jumper. The chip runs a 10-event FIFO so key presses and releases queue up instead of getting lost, includes hardware debouncing, and supports a programmable two-key lock and unlock sequence. Soldered Arduino and MicroPython libraries are available that decode the raw FIFO events into key press and release events you can use directly, without dealing with row and column scan codes yourself. Two Qwiic connectors handle the wiring without soldering.

The board runs on 1.65V to 3.6V, draws about 3 µA in standby, and is rated for 2000V HBM and 1000V CDM ESD protection on every pin. It measures 136 x 60 mm, with two mounting holes sized for M3 screws.

• IC: TI TCA8418
• Keys: 80 tactile switches, 8x10 matrix
• Communication: I2C, up to 1 MHz (Fast Mode Plus)
• I2C address: 0x34 (fixed)
• Event buffer: 10-event FIFO
• Debounce: Hardware, 50 µs
• Lock/unlock: Programmable two-key sequence
• Operating voltage: 1.65V to 3.6V
• Standby current: 3 µA
• ESD protection: 2000V HBM, 1000V CDM
• Software: Arduino and MicroPython libraries available
• Connector: 2x Qwiic
• Mounting holes: 2x M3 (3.2 mm diameter)
• Dimensions: 136 x 60 mm