i2c / SPI character LCD backpack - STEMMA QT / Qwiic

Character LCDs are a fun and easy way to have your microcontroller project talk back to you. They are also common, and easy to get, available in tons of colors and sizes. We've written tutorials on using character LCDs with an Arduino (or similar microcontroller) but find that the number of pins necessary to control the LCD can be restrictive, especially with ambitious projects. We wanted to make a 'backpack' (add-on circuit) that would reduce the number of pins without a lot of expense.By using simple I2C and SPI input/output expanders, we have reduced the number of pins while still making it easy to interface with the LCD. Only 2 pins are needed for I2C, 3 for SPI. For Arduino and CircuitPython/Python users, we provide an easy-to-use library that is backwards compatible with projects using the '6 pin' wiring. This backpack comes with pre-soldered 2-pin and 3-pin terminal block to make a 5-pin terminal for easy wiring.