If you are like me and backed the Digispark tiny Arduino compatible dev board and got the LCD kit, you have a nice 16 char, 2 lines i2c lcd display which works fine with a digispark. But when trying to use the display with my Arduino Uno I ran in several problems. But to get it working is really trivial if you know how to do it.
The default LCD code in the Arduino samples doesn’t work. You need another library which can be found here under Documents: http://www.dfrobot.com/image/data/TOY0046/LiquidCrystal_I2Cv1-1.rar.
If you’re running linux like me, you have to delete the LiquidCrystal folder in /usr/share/arduino/libraries and put the content in a folder there, maybe correct the access rights to the folder and you’re ready to go!
Connect the SCL pin to analog pin 5 and the SDA one to analog 4 if you’re using an Uno model one, the later versions have dedicated SCL and SDA pins. Connect ground and VCC (5V) accordingly and have fun with your display and arduino :)