Starfield Ceiling Controller

Looking for advise on how to best connect some items on my Controller Project

I have Push Buttons via Digital I/O Pins and a 20x4 LCD Via I2C Bus located on a paned in the Equipment Rack

I have Multiple NeoPixel devices connected to various Digital I/O Pins

It is approximately 20 Feet from the NeoPixel Light Sources for The Fiber-optics
( Very Limited Access to the LED's in the Ceiling Panels ) to the Panel where the LCD and Switches are located

I can power the NeoPixels from either the Ceiling Location close to the NeoPixels or Close to the LCD Panel Location or Both

I need to have ability to reprogram the UNO Board to be able to make code changes if needed after the Ceiling Panels are closed up

So What do you think would be the best method Mount the Arduino Board Close to the LCD Panel location where I can easily access the Board and then connect the NeoPixel devices via Multi conductor wire.

Or Mount the Arduino Board in the Ceiling with limited access with a USB over Cat5 and connect the I2C LCD and Switches via Multi Conductor wire

If I have the Long runs will I need some type of Driver Board between either the NeoPixels or the I2C LCD board

Thanks
Ed

If I have the Long runs will I need some type of Driver Board between either the NeoPixels or the I2C LCD board

Yes both.

Mount the board close to the devices to avoid drive problems.

I thought that some of the wireless options will allow you to program your unit wireless ?

I think USB has a limitation of 5 meters.

I2C, with the right pullup resistors, can go ~75meters over Cat-6. (51pf/meter, 4000pf devices)

Don't know about NeoPixels.
Leo..

Edit: Saw a neopixel datarate of 800Khz.
That would limit the distance (first Neopixel) over Cat-6 to ~6-8meters without straining the Arduino too much.
I would test that first...

No it is not 4000pF but 400pF.
See this discussion

2012 post...

100khz/400pf is the standard mode
There are several new modes now.

Fast mode, Fast Mode Plus and High Speed Mode.

Leo..

2012 post...

Wow when did the laws of physics change then.

There are several new modes now.

Fast mode, Fast Mode Plus and High Speed Mode.

Any super slow mode? That is what you need.

Don’t be a smartass.

Not easy to find the right info on the net, but this might help.

Drive current for Fast Mode Plus has increased from 3 to 30mA, so pullup resistors can be smaller.
Bus speed has increased to 1 Mbit/s, but can be traded against load capacitance (wire length).
I am using a Mega and two PCA9685 boards (Fast Mode Plus) with 8 meters of Cat-6 between them, running 24/7 at the standard 100Khz.
Leo…

Look speed at 400KHz has been around since the 1990s there is nothing new. It is only available to devices that can use it. Going up in speed when you want a long cable is just stupid. You need to drop the transfer speed to stand any chance of getting what the OP wants. He would be better off using a bus driver to increase the distance. There is no way you can get 75 meters without. Why did you suggest you could go that far?

Sorry, edited post #7. Fast Mode is 400Khz. Fast Mode Plus is 1 Mbit/s.
Theoretical distance of Fast Mode Plus with Cat-6 wire with one twisted pair carrying one bus wire and ground, and the other twisted pair carrying the other bus wire and 5volt.
The Cat-6 twisted pair I'm using is 51pf/m.
I have read somewhere that 4000pf/100Khz was possible.
I am planning to extend my home lighting system soon with another 20meters, so I could keep you updated.
Leo..

In post #3 you said:-

Wawa:
I2C, with the right pullup resistors, can go ~75meters over Cat-6. (51pf/meter, 4000pf devices)

Like to edit that one as well.

When I got time, I will see if it's true or not.
At the moment I have a stable link over 8 meters with 3k3 pullup resistors.
Leo..