LCD and Digital Input


sorry my english is not so good.

I use an Arduino Mega with LabView.

I have a LCD-Display.
The LCD alone is okay and the Digital Input alone ist okay.

If I use the LCD-Display and the Digital Input together, then the Digital Input change 0,1,0,1,0.... (In LabView) constantly.
The Digital Input is over a 1k Ohm Resistand with Gnd connected.

Is the pin floating (set as INPUT and not connected to anything trying to set it one way or the other)? Floating pins will transition in response to local electromagnetic fields (effectively at random).

Are you trying to read a pin that's also being used to communicate with the LCD? That won't work.

There isn't much we can do to help you, since you have not posted your wiring or code.

The config in Labview with Arduino - LCD-Config

Is here Nobody who can help me?

In my Post bevore this one, i have included a Picture of my circuit.

Digital input pulldown resistors should be no less than 10 k ohms. You have 1k (R1,R2).
Replace R1 & R2 with >= 10k ohm, like 20 k.

What is your 5V power source. What exactly IS that 5V ? Is a jumper wire coming from the arduino 5V pin or is that an external 5V power supply ? What is it ?

Your life might be a lot easier if you use the internal pull-ups and wire the switch directly between the pin and the ground.

Note that in that case the logic is inverted (switch closed gives low, not high).

As simple as I can say it. Your drawing does not match what you want to do.

I use the 5V Pin from the Board and I have replace the 1k with10k.

The problem is still there.

I don´t know how i activated the internal pull-ups, because I program with LabView.

Sorry I am beginner with Arduino :wink:

The Digital Input and the LCD only is okay, too.
LCD and Digital Input together I get Problems.

If I use the LCD-Display and the Digital Input together, then the Digital Input change 0,1,0,1,0.... (In LabView)

We're not interested in what happens in Labview . This is a General Electronics forum. Is there or is there not a physical LCD display ?
Is there or is there not a physical arduino ?

Where is your code ? Post your code .
If you load the sketch into the arduino and DO NOT use LABVIEW, what happens on the display ?

Post a photo of your circuit and test it without labview and then report back.
We cannot help you with Labview issues. You will have to find a Labview forum for that.
If you can post for an issue that exists using only the arduino and the LCD WITHOUT LABVIEW, then we can address that issue. As it stands now , we can not help you until you eliminate Labview from the equation by testing the hardware (arduino, switches and LCD ) without using LABVIEW.