{"title":"Adafruit TCA8418 Keypad Matrix and GPIO Expander Breakout","handle":"adafruit-tca8418-keypad-matrix-and-gpio-expander-breakout","url":"/products/adafruit-tca8418-keypad-matrix-and-gpio-expander-breakout","description":"The Adafruit TCA8418 Keypad Matrix and GPIO Expander Breakout is a versatile I2C GPIO expander and keypad matrix driver. With 18 I/O pins (10 columns and 8 rows), it can manage up to 80 switches in a matrix configuration or serve as individual GPIO inputs and outputs.\n\nWhether you need more buttons, LEDs, or a full keypad matrix for your project, this breakout handles it all over a simple I2C connection. It features a 10-element event queue so key presses and releases are stored even if you can't respond to the interrupt immediately. The built-in STEMMA QT connectors and onboard 3.3V regulator with level shifting make it compatible with both 3V and 5V microcontrollers.\n\nKey Features\n\n\n18 I/O Pins – 10 columns and 8 rows, configurable as a keypad matrix (up to 80 switches) or individual GPIO\n\n10-Element FIFO Event Queue – Stores key press and release events so you never miss an input\n\nI2C Interface – Easy to connect and share the bus with other sensors and devices\n\nGPIO Inputs with Pull-ups – Optional pull-up resistors, interrupt output on INT pin for rising or falling signals, and built-in debouncer for noisy tactile switches\n\nGPIO Outputs – Set pins high or low for basic LED driving\n\nInterrupt Support – Configurable interrupt output on key press or release, no need for constant polling\n\nSTEMMA QT / Qwiic Compatible – Solderless STEMMA QT connectors on both sides, compatible with SparkFun Qwiic\n\n\nOnboard Voltage Regulation – Built-in 3.3V regulator and I2C level shifting for 3V or 5V microcontrollers\n\n\nIdeal For\n\nCustom keypads and button matrices\nExpanding GPIO on pin-limited microcontrollers\nLED control arrays\nProjects requiring interrupt-driven button input\nI2C sensor and peripheral chains\n\n\nPackage Contents\n\n1× Adafruit TCA8418 Keypad Matrix and GPIO Expander Breakout\n\n\n\nNote: A STEMMA QT / Qwiic cable is required for solderless connection and is not included. Browse our range of Qwiic cables to find one that suits your setup.\n\n\nResources\n\nArduino Library (GitHub)\nCircuitPython / Python Library (GitHub)\nLinux Kernel Driver Module\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":1922,"title":"Default Title","sku":"AF-4918","price":12.24,"on_sale":false,"in_stock":true,"available_quantity":100,"option1":"Default Title"}]}