Sorry in advance if my description is not clear but I am quite new with arduino.
I would like to use your expertise and hear from you what you believe it is the best solution for my installation.
I am working in a light installation where I will have 300 LEDs that will be controlled individually by Arduino, so as far as I understand each LED will be connected to a pin is that right?
so
What would be the best option to have 300 LEDs controlled individually considering all the LEDs should respond to the same sketch? one arduino board or multiple arduino boards?
If it is one arduino board, how do I extend the number of outputs? using a Shift Register?
If it is multiple arduino boards, would this allow me to have the LEDs responding to the same sketch? I mean would be possible to connect one arduino to another?
What is the best arduino board to use in this case?
Use a set of 5 MAX7219 chips, each will control up to 64 LEDs.
I have this little breakout board that provides two connections for each LED. The MAX7219 takes care of current control. The boards are designed to be daisychained.
Matrix was not mentioned. 2 wires per LED out to wherever they are going is not hard to manage. Can be 30 guage wirewrap wire on the LEDs back to male pins on the board (or stuck in the female headers). Twisted pair pulled from CAT5 cable for something a little sturdier. (26 guage)
Individual brightness was not mentioned. Each MAX7219 also offers 15 levels of overall brightness control.
I would look at WS2812, really easy to use. Can be bought on a self-adhesive strip which makes installation easy, or on carrier boards for ad hoc layouts. Only need one IO pin.
Could work out same price or cheaper than multiple MAX7219 etc, and with individual RGB control a better solution.
First of all I just want to thank you all for a very quick response. This is what I call a collaborative community.
Ok now answering to some questions:
fungus:
a) Do you need RGB?
b) Do you need brightness control?
c) How are they arranged physically? in a long string? A neat matrix? Randomly?
a) at the moment they are one colour only (white) and I don't need RGB but I would like to hear what are the options in case I do. I mean does it affect how they will be wired up?
b) Yes, brightness control is essential
c) I haven't made a final decision on the design yet but hey will be arranged either in a neat matrix or randomly
The Adafruit and WS2812 are indeed great options, Is there a difference between them in terms of controlling each LED individually?
If it makes easier for you guys to picture what I am doing and therefore easier to give an opinion about what I am trying to achieve,
The basic idea is that I will have either a IR Range Sensor or a Ultrasonic HC-SR04 to detect people presence when approaching a specific place, once the person reaches a specific point one LED will light up and once the person moves away the light fades away, once a second person reaches the same triggering point the first LED will light up and also a second (new) LED will light up and as the person moves away they will fade away., this will carry on and on until 300 people pass by the installation and all the 300 LEDs will light up. I hope that is easy to understand.
The Adafruit and WS2812 are indeed great options, Is there a difference between them in terms of controlling each LED individually?
Not sure what you mean. The way you control them is you send a bunch of numbers out. The numbers get shuffled along each LED chip and when they stop being shuffled up the individual LEDs gets to light up according to the number that ended up in that controller. You can lay out these strips either as a random meandering of the strip or in rows.
As far as I know the strips you can buy are all RGB because each controller chip, each WS2812, can control three LEDs. So you could make your own strips using a monochrome LED and have three chips per controller, but that would be a lot more work than buying strips.
This picture is part of a project I did earlier this year that had about 300 LEDs in a matrix behind a diffusing screen. It features two of my collaborators on the project.
