As pointed out you likely don't need any level shifting. Most 5V I2C inputs have logic thresholds compatible with 3V logic. But for reference... http://www.nxp.com/documents/applicationĀ_note/AN10441.pdf
@CanyonCasa started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
As pointed out you likely don't need any level shifting. Most 5V I2C inputs have logic thresholds compatible with 3V logic. But for reference... http://www.nxp.com/documents/applicationĀ_note/AN10441.pdf