I am in early stages and planning a 900 LED infinity mirror table. 3 rows, each row consisting of one 5m WS2815 strip. I plan on running FastLED library to run some similar visuals that can be viewed at this link.
I plan a 12V 40A supply for the lighting, 5V 3A for an Arduino Mega running the data line.
A few questions come to mind.
Given the amount of LEDs in the build, should the delay be a concern? I have read several other posts talking about delays down to ~20fps but with this being my first project I cannot visualize if that is going to be a terrible rate.
Can I / Should I look to run a new data line to each strips Din from a new pin on the controller? The wire runs will be very short, like <20cm and equal length. I am new to the coding side for FastLED, would multiple data pins for each strip be obtainable in the code for the desired effects?
I see some posts referencing the use of a resistor in series to the Din of strip 1, but cannot find the reasoning for this? Given the length of my data run, is a resistor suggested, and why? How do I determine the proper size?
Same as point 2 above, but I have seen limited mention of capacitors on the 5Vdc power supply to the arduino. Should I be doing this? Why? Sizing? Or not a concern since I am powering the WS2815 with a separate 12V souce?
Each WS2815 uses 15mA at max power, which means that for 900 LEDs, you would need a 12VDC, 13.5A power supply or more. I think 40A is a little overkill. The Arduino Mega would work with a 5V 1A USB charger port just fine.
I'm not sure about the delay, but I highly doubt it will be a problem.
One data pin for all of them should work.
Usually a resistor of about 470Ω is used on the data line to help filter out noise.
A capacitor on the 5V power supply should not be needed. The Arduino already has capacitors for that on the board.
Thanks for your comments. Sounds like I am on the right track so far. What kind of 'noise' would one expect in this scenario? I see some mention of no resistors, or lower values being used.
Should I start with no resistor and see what happens? I just don't know what to expect for noise and I would hate to jump right in and add a resistor, if its not needed.
Sometimes there is slight variations in the data signal, so the resistor is there to help even them out. You could try it without the resistor, and if you notice anything a little off, like certain LEDs not lighting or lighting the wrong color, or being a little delayed, just add one. Usually a 220Ω, 330Ω or 470Ω would all be fine.