You don't say which library you are using, but most I have seen do not allow the printing of floats with sprintf. You need to use lcd.print() instead. The lcd will show ? where the float is to be displayed.
You don't say which library you are using, but most I have seen do not allow the printing of floats with sprintf. You need to use lcd.print() instead. The lcd will show ? where the float is to be displayed.