Max cable length for LCD touchscreen?

I was wondering if I could remote-box a screen for a project im making with mega 2560.

More specifically, this one.

There's a lot of modules involved that turn the mega into a bit of a bulky lump, and having the screen right on it would be a bit clunky to operate. So I want to use a 40 pin cable to move the screen somewhere more convenient. Only the question is, how long can I make it before it goes funny?

Has anyone ever tried putting an LCD on a wire? How did it go?


I have successfully used connection cables about 20cm to 30cm, standard flat cables with self-cutting connectors. Maybe even 40cm. But this was some time ago.

For longer cables you would need damping resistors on both ends against reflection spikes.

I once tried 20cm at both ends, with jumper wires in between, with horrible result.
The same worked with the jumper wires at one end, to adapt wiring.

A HF-engineer could tell you more, I think the hf-impedance "Wellenwiderstand" of the flat cable is about 600ohms. But I may be totally wrong.


I've read that lengthening the cable would screw with the clock speed of the screen, and that you would have to slow it down to prevent it clashing. In other words, for the 1 meter I was looking for, it would be too much trouble to be worth it.

So I've decided to move the whole control unit, mega and all, to its own enclosure. It's not as pretty as the handheld remote I wanted, but it will do.

One meter is a critical length. Think about the frequency a wavelength of 1m corresponds to.
But 1m IDE or SCSI cables inside PC cabinets did work, so it could also work with displays.

But for remote, SPI or even UART connection is a better choice.