
Building DIY LED strips for fun - MindGods
https://a.wholelottanothing.org/2020/07/18/building-diy-led-strips-for-fun/
======
KirinDave
If you came here hoping for _good_ resources on how to set up and control LED
strips, angry that the article linked was bad and devoid of any good details,
here are some useful resources.

#1: AdaFruit loves you and has a guide: [https://learn.adafruit.com/adafruit-
neopixel-uberguide](https://learn.adafruit.com/adafruit-neopixel-uberguide)

#2: Andreas Speiss has a phenomenal youtube channel that offers a lot of solid
tips and tricks for new makers looking to avoid common pitfalls:
[https://www.youtube.com/watch?v=IIl5nDjfkjY](https://www.youtube.com/watch?v=IIl5nDjfkjY)

#3: GreatScott! (another great youtuber) has a really fun article on what I'd
label a very "intermediate" LED project to get a sense of how to put
everything together to make a unique object that is not simply a matrix and a
lot of software:
[https://www.youtube.com/watch?v=tXfMg8y1Fs4](https://www.youtube.com/watch?v=tXfMg8y1Fs4)

Good luck, and one last tip: remember to be careful that your microcontroller
may be fried by the voltage your LED strips needs. It may seem that there is
an obvious solution to that which is, "Just use 2 power supplies" but with
3-wire LED strips group loops can exist and ruin your ability to control the
strip. Don't despair, search for "buck converter board" and then look up how
to tune it. You'll get a system efficient enough that you can drop 12v to 3.3v
and it won't drain your battery or overhead your enclosure. Linear regulators
are _not_ your friend, they're usually cheaper specialist tools for folks who
care about radios.

~~~
conk
As for voltage difference between controller and lights, you can sacrifice the
first led and power it at 3.3v and power the remaining ones from a second
power supply. The first led will be a little dimmer than he rest but this
setup has been very stable in my tests.

~~~
andruby
How does that work? Do I understand correctly that you connect the first led
to a esp32 (+3V, onewire, GND) and then connect +12V and GND to the second
led?

I wonder why it wouldn’t work if you connect +12V on the first led?

~~~
avianlyric
The LEDs in the article are WS2812B LEDs that operate at 5v rather than 12v.
5v is a slightly more "normal" LED voltage, 12v strips are usually going
little tricks like have 3 or LEDs in series and using that to get the required
12v drop.

With the WS2812B you're issue is that they operate on 5v logic for
communications. 3v logic from a chip can _just about_ communicate with 5v
devices. But you can't send the signal very far before the voltage drop stops
communication. The cheat here is to use a single WS2812B LED as logic voltage
converter. You put a resistor in line so it's operating at ~4v, give it a 3v
logic signal it can understand, and it'll then talk down stream using ~4v
logic, which you can then pump into normal 5v LEDs.

You can find detail of this little trick on hackaday[1]. But it's specific to
WS2812B type LEDs that are really microcontrollers that happen to also put out
light, rather than traditional dumb LEDs that have no smarts.

[1] [https://hackaday.com/2017/01/20/cheating-
at-5v-ws2812-contro...](https://hackaday.com/2017/01/20/cheating-
at-5v-ws2812-control-to-use-a-3-3v-data-line/)

~~~
SK6812away
IME, you can use 3.3V logic with 5V WS2812B/SK6812 strips, no trouble.

Each LED reforms the signal before sending it to the next LED in the chain, so
voltage dropping over distance shouldn't a huge issue for the logic line
unless the strip is very far away from the controller.

And the datasheet almost agrees with my experience; the "high" voltage
threshold is listed as 0.7×VDD, and 0.7×5=3.5V. That's a bit over 3.3V, but I
haven't had any issues across several projects. Maybe it's because many USB
supplies provide a little over 5V to account for droop? Maybe the datasheet is
slightly pessimistic? Maybe 0.7 really means 2/3? Whatever the reason, it
simplifies the wiring for small displays.

Here's my favorite reference for the single-wire protocol that these LEDs use,
since everyone seems to be chiming in with one:

[https://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-
so-f...](https://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-
once-you-get-to-know-them/)

~~~
KirinDave
I think maybe folks got the model number confused. There are strips where the
entire signal is passed verbatim without being reformed to every package on
the line, but everyone stopped using them because they're awful.

In my experience, slow microprocessors are WAY more tricky to deal with than a
3V3 logic voltage for these strips; and often lead to crazy hacks. I'd way
rather just put a modestly powerful resistor or a buck converter in my project
than deal with trashy old Atmel chips, given how absurdly cheap ESP32 and ARM
M7 packages are.

------
solarkraft
This is a nice, interesting, useful article, but the title is garbage.

Step 1: Buy some WS2812B strips.

You're not building the strips. You're building the control infrastructure.

~~~
KirinDave
I believe the word you're searching for here is "clickbait."

Controlling LED strips is not a boring project and it's a wonderful entry into
the hobby since it often works with very safe voltages and is happy with cheap
components.

But this article is clickbait, and it's probably the most detail-free article
imaginable on the subject.

~~~
xxs
> works with very safe voltage

True for constant voltage, resistor limited current ones only. With constant
current LED drivers, the voltage is approx 3V per LED. So it adds nicely to
unsafe levels, albeit DC.

Another note is the power supplies can be quite unsafe too - esp. the cheap
off-brand ones.

~~~
KirinDave
Panels and strips using more than 24V are extremely rare, with 12V being
common and 5V existing for the hobbyist crowd. I've never seen a 24V rig for
hobbyist uses (although some Ikea strips run there).

You don't wire them in serial anyways. In general if you care about blocks of
LEDs at all you don't wire them in serial.

------
flywheel
LEDs get a lot of attention from people without any kind of training with
electronics, but they aren't as simple as people think - LEDs consume _a lot
of power_. If someone isn't careful and doesn't know what they are doing, it's
very easy for them to create a fire hazard.

[https://hackaday.com/2018/01/29/the-engineering-case-for-
fus...](https://hackaday.com/2018/01/29/the-engineering-case-for-fusing-your-
led-strips/)

~~~
fock
good to see that! I (physics grad) was eyed very skeptically by a crowd of CS
and architecture (like in houses) people, when I started buying fuses and
caring about fire-safety (all the people were much like: oh light, wow (whilst
I was: power, hot)

------
Tempest1981
This one on "self organizing LEDs" was fun and motivating:

[https://news.ycombinator.com/item?id=23741036](https://news.ycombinator.com/item?id=23741036)

Video: [https://youtu.be/Ueim2Ko8VWo](https://youtu.be/Ueim2Ko8VWo)

~~~
flywheel
Pretty simple to do this honestly, it's been done many times before. There are
phone apps that do this that have been around for a while. After all it's just
assigning an x/y value to a position that a color was detected at.

------
kejaed
That looks really slick. Nice job!

These sorts of projects can be a lot of fun. I did the same sort of things a
couple of years ago on my deck.

I had a rpi and Arduino in the loop cause that’s what I had lying around, the
ESP solution sounds much simpler.

Then we moved a couple months later...

[https://imgur.com/gallery/E4lbU](https://imgur.com/gallery/E4lbU)

------
d33lio
Adafruit is an amazing source, their NeoPixel ecosystem is exceptional. They
also offer an RGB NeoPixel strip variant with modules that ALSO have a
dedicated "warm" or "cold" white LED module. This is great in case you want to
actually use your LED's as non color LED's for some time.

------
Havoc
I found this to be a rabbit hole. e.g. Ideally you want 24V not the 12V most
of the cheap stuff is. And then you really want one that has warm white LED
instead of just RGB'ing the white.

...and pretty soon you're looking at real money

~~~
chrismorgan
Why 24V? What does it improve?

~~~
xxs
Power is proportional to the voltage squared (P = V * V /R), so the power
supplies need less current -- cheaper, more reliable - less heat, less voltage
drop.

The same holds true for the power supply in NA vs most of the world (save
Japan). 110V vs 230V - much less copper needed for conductors. motor windings,
etc.

Flip note: the better option is using constant current drivers, for higher
efficiency (they might have unsafe voltages, though)

