Do you have a 3.3V I2C or SPI sensor that might go up in smoke if connected to a 5V Arduino? Or a 5V device that needs a workaround to be compatible with your 3.3V Raspberry Pi, Arduino Due or pcDuino?
To get over this obstacle you need a device that can shift 3.3V up to 5V or 5V down to 3.3V. This is called logic level shifting. Level shifting is a dilemma so common we designed a simple PCB assembly to make interfacing devices a little easier: the Bi-Directional Logic Level Converter.
Though they’re share the same shape and size, this bi-directional logic level converter shouldn’t be confused with the more “uni-directional” version. This converter can pass data from high to low and/or low to high on all channels. It’s perfect for level-shifting between devices that are sharing a data wire, like I2C or a one-wire interface.