Have you added pullup resistors on SCL and SDA? That's the No.1 problem with I2c usually :)
@Gordon 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.
Have you added pullup resistors on SCL and SDA? That's the No.1 problem with I2c usually :)