Help With Hobby Project- LED array

Thread Starter


Joined Dec 7, 2023
Hello there,

I'm currently trying to get a massive greatsword to light up using an LED array that goes up the blade controlled by a hold button. This isn't my first lighting project, but it is my most ambitious so far. I'm in the pre-prototype phase right now. I'm still trying to work things out on Tinkercad.

I've successfully gotten the vision I wanted in terms of a slow fade-out upon the release of the button. However, I just can't seem to figure out how to get it to fade-IN.

I know I should be using a capacitor in some capacity (ha) and transistors too, but no matter where I put them in the circuit it seems to break the array.

I would be ever so grateful for some assistance. I've tried getting some tutorials, but they all use breadboards or are explained in a very confusing way. Tips, pointers, and suggestions would be greatly appreciated. Clear pictures would be extremely helpful.

Thank you in advance


Joined Mar 30, 2015
Welcome to AAC!
What is a "greatsword"?
the blade
Need some context. If it's not important, why mention it?
I've successfully gotten the vision I wanted in terms of a slow fade-out upon the release of the button.
How did you do fade-out?
However, I just can't seem to figure out how to get it to fade-IN.
A schematic would be helpful. As would a bounds on solution complexity (area constraints, complexity, supply voltage, current draw of the LEDs being faded, etc).

I'd go for a PWM based solution. A single comparator solution could do it. Frequency varies, but it sounds like you only care about duty cycle.

How is fade-in initiated? How long to you want it to take?


Joined Jan 27, 2019
Welcome to AAC.

There are quite a few possible solutions the way the problem is presented. I get the impression you are trying to “simplify” the solution—but a naïve simplification may actually be a complication and also miss an opportunity to include more (future) functionality with very little effort.

For example, a small MCU (microcontroller unit)—you might say “Arduino” but that’s very misleading—and some WS2812 or similar RGBW addressable LEDs, and a single 8-pin chip (e.g.: ATTiny 85A) along with a few passives (resistors, capacitors, etc.) and some MOSFET transistors could provide the functionality you describe in software as well as reactive color changes (add a small sensor) and any other thing you can imagine having the lights do.

Yes, there is a learning curve, but—oh boy–do you get magical powers in return for the investment. I really think it is worth you consideration, and of course, you can get copious help here. (It’s also an amazingly fun and satisfying thing to have so much control over how your projects behave).

In any case, you should write up a “user story”, that is, what does using the sword as you conceive it look like to an end user.

Then describe any (real) constraints (physical sizes, ruggedness requirements, components that must be used, &c.).

Then provide a description of what you have tried, including schematics or at least wiring diagrams, and a BoM (Bill of Materials) with the part numbers of the components you are using and supplier links where possible.

Sharp, well lit photos are always a huge plus as well.

Good luck with your project, please consider taking the leap into the scary but amazing modern world of cheap and powerful MCUs and all of the amazing modules, hardware, and example code at the fingertips of those who dare to challenge themselves. I promise you the fearsome aspect of learning it is an illusion.


Joined Jan 27, 2019
Yeah, if you and I can do it, any genius can. :)
I’m not basing it on me. I am basing it on my experience teaching people who have a purely practical need to use MCUs and the Arduino IDE.

I’ve found that for a person who does other craft-oriented things, the biggest stumbling block to success is an erroneous belief they are simply unable to, or it will take more effort than they are willing to muster.

But for purely practical applications understanding the principles, while very useful, is not mandatory. Knowing how to stick the bits together and use other people’s electromechanical designs and code makes using the whole Arduino ecosystem entirely possible.


Joined Oct 2, 2009
"greatsword" - I had to think about this twice. I think he meant "great sword".
LED fade-in fade-out.jpg

I cannot give you specific component values because it depends on supply voltage and LED currents.