For background, I am a complete noob with Arduinos and have yet to program one. I am currently completing my major project for my electronics course in high school. I am making a stereo system which includes non music reactive LED effects. The LED strips purpose is to illuminate the acrylic sheets that will be on the front of my speaker cabinets. I am looking for a bit of guidance and opinions on the circuit design for the LED's. I made a quick design using paint for lack of better software, using information I gathered from other forums and such. [arduino led] The LED strips will be ws2812b's @30LED/m and the Arduino will probably be a Nano (open to suggestion). I also want to include a switch somewhere to turn the LED's on and off but wasn't sure if the Arduino should be included. The power and data cables for each is going to have to be around 1m length as the speakers and amp are in different boxes, so I want to try and avoid voltage drop. Just to add, I am aware that the power consumption of each LED is 60mA at full brightness and have already made sure to consider that on top of the amplifier when buying the power supply. Also as an extra, is it possible to have programmed pre-set LED effects that can be cycled with an external button hooked up to a data pin rather than changing it through fast LED software? e.g. rainbow cycle -> press button -> blue/purple gradient cycle...

[image] davidw2: ws2812b I am confused, when I look up the WS2812B I get a variety of LED products. It can be an individual smart LED chip, but they are also sold as strips with up to 300 LEDs, and panels that has a 16x16 array, maybe more if I kept looking. Perhaps you can provide more detail on exactly what the LEDs will be. I assume you are using an Arduino to generate the serial data to control the lights, so that control function can effectively act as an on/off switch where the LEDs go dark and draw almost no power. The switch can be used to kill power to the Arduino, but then don't expect it to remember what color pattern or speed it was using. You can input the switch to the Arduino and tell it to drive the lights to dark, and it will still remember what it was doing. I'm not sure if you have something particular in mind when you write "programmed pre-set LED effects". I assume you want to pre-program them in the Arduino, and in that case you can have your program read switch inputs to determine what pre-set LED program to display. I guess what I really don't understand is your mention of "fast LED software". As for the programming, you can pretty much get the LEDs to do any patterns you want as long as you learn how to do Arduino programming. I think the challenge will be generating the serial data for the LEDs, but after that it might actually be fun creating color patterns!

Hi, @davidw2 Welcome to the forum. Please read the post at the start of any forum , entitled "How to use this Forum". [image] How to get the best out of this forum IDE 1.x See also FAQ - Arduino Forum for general rules on forum behaviour and etiquette. Hello, Welcome to the Arduino Forum. This guide explains how to get the best out of this forum. Please read and follow the instructions below. Being new here you might think this is having rules for the sake of rules, but that is not the case. If you don’t follow the guidelines all that happens is there is a long exchange of posts while we try to get you to tell us what we need in order to help you, which is fru… If you google arduino neopixels You will find all sorts of tutorials and projects using the WS2812b strips. Thanks.. Tom.. :grinning: :+1: :coffee: :australia:

The WS2812B in simple terms is a type of LED with a certain chip that allows the LED's to be individually addressable, and in my case I plan on using these in the form of LED strips. Pretty much 2 sets of 1 meters worth of 30 LED's in a single, long line. The "fast LED software" terminology I mentioned was incorrect, my bad. I was referring to the Fast LED library which can be used on the Arduino to control these LED's, with most of the work already done. You mentioned killing the power to the Arduino, potentially creating problems, or setting it up so the lights are set to dark/light, which is fair enough. But to me it makes more sense to kill power to the LED's instead, and as soon as they are turned back on they continue to what the Arduino is telling it to do. Or better yet cutting the power to both?

Believe it or not I found a guy who explains how to cycle between different colour pre-sets with a button. Thankyou for the obvious but great suggestion! :australia: :call_me_hand:

OK, so you specify two strips each of one meter with 30 LEDs per metre, so just 30 LEDs in each. Maximum current draw at 55 mA per LED would be 3.3 Amps. You want a supply rated at 5 Amps to be sure. If you power down the LEDs, when you turn the power back on, they should be dark. Now when dark, they draw 1 mA per LED, so 60 mA total. Since you are powering this from the mains, it makes no sense to actually switch them off, just use the program to set them to dark. 60 mA is similar to the current drawn by the Arduino. 120 mA total at 5 V is 600 mW - less than a Watt. I think you can afford that power drain. (If you cannot, you should not be using any appliances at all!) Your "Voltage Dropping Circuit" however needs to be a switchmode "buck" converter, not a linear regulator. Use at least 2 mm² cable to power the strips and keep both power wires and the data wire together wherever they run. Maybe 1 mm² power cable would suffice. [image] davidw2: Believe it or not I found a guy who explains how to cycle between different colour presets with a button. It is an extremely common desire. :sunglasses:

Appreciate the input :+1:. Just a question about the voltage stuff, my teacher had designed a circuit for a previous student who was also using 5V LED's with a 12V power supply. From memory it had two voltage regulators, can't remember if there was anything else but I assume this is a linear regulator. Why use a a switch mode buck converter instead? From a google search, switch mode buck converters step up the output current rather than dissipate the extra power as heat, so I suppose that's why?

[image] davidw2: From a google search, switch mode buck converters step up the output current rather than dissipate the extra power as heat, so I suppose that's why? Indeed. Switchmode converters are efficient. (i was about to say "far more efficient" but that is wrong. You simply cannot call linear regulators "efficient" in any respect. :roll_eyes:) To drop 12 V to 5 V at 3.3 Amps would dissipate 23.1 Watts, you waste much more power in the regulator than the circuit proper uses. And you requite a large heatsink, if not a fan. Switchmode "buck" converters are now cheap and small. Using a linear regulator is just ridiculous.

Well you learn something new everyday huh. Thanks for that :grin:

Maybe WS2815 diodes directly at 12 volts. Here https://www.derunledlights.com/the-difference-between-addressable-rgb-led-strip-ws2811-ws2812b-ws2813-ws2815-sk6812-sk9822/ is more info.

[image] davidw2: From a google search, switch mode buck converters step up the output current rather than dissipate the extra power as heat, so I suppose that's why? The way I summarise it for beginners is to say they swap voltage for current; so high voltage low current in becomes low voltage high current out.

Powering and Controlling Separate LED Strips

Projects General Guidance

TomGeorge May 23, 2021, 6:34am 3

Hi, @davidw2
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".

If you google

arduino neopixels

You will find all sorts of tutorials and projects using the WS2812b strips.

Thanks.. Tom..

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