Microcontrollers are getting smaller and cheaper, but sometimes a bit too limiting when you ‘ve found you’ve run out of digital I/O lines. SparkFun’s solution is this: the Qwiic GPIO expander that uses the the I²C communications standard via the TCA9534 I/O Expander IC to add 8 channels to your project. 8 channels not enough? Daisy-chain up to 8 units for 64 additional channels of data!

Fortunately, SparkFun has made it easy to use in an Arduino library so you can call functions similar to Arduino’s pinMode and digitalWrite, so no “creative coding” is required.

The TCA9534’s pins are broken out to easy-to-use latch terminals; never screw another wire into place! The terminals are relatively roomy themselves, so feel free to latch multiple wires into a ground or power terminal. With three customizable address jumpers, you can have up to eight Qwiic GPIO boards to be connected on a single bus allowing upwards of 64 additional GPIO pins! The default I²C is 0x27 and can be changed by adjusting the jumpers on the back of the board.

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