Hi, I have an Arduino Mega 2560 and I've got a Nokia 6100 Knock-off LCD screen and an RN41 Bluetooth module. I'm planning to have the arduino control some motors for a telescope and have a laptop send signals to the arduino telescope controller via bluetooth and to have it display various things on the LCD screen to aid debugging and so on.
I can control both from the arduino using serial communication but my problem is that the i/o pins on the arduino are 5v TTL but the screen & bluetooth are both 3.3v CMOS. A while back I came across an IC that allowed bidirectional communication between the 2 - a kind of buffer / translator thing, with them both being electrically isolated from each other. Now I come to try to do the programming and electronics I can't seem to find the chip I identified a while back as being what I needed.
I want a single IC solution without having to fiddle with putting in any extra resistors / capacitors etc. Does anyone know of any suitable chips ? Do I need something from the 74HCT family or are there any optocoupler type things that would be better ?