I'm WAY out of my depth

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rudimentaryrobonoids
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I'm WAY out of my depth

Not totally sure if this is the best place to post this so please bear with me!

So, I’ve found myself in an area where I have ZERO knowledge. I know nothing about what I’m trying to do here so I’m anxiously crossing my fingers hoping that after several youtube videos and articles that I’m on the right path. But now I need some more specialized expertise.

I’m attempting to build an LED flow wand. For those who are wondering:https://shop.astralhoops.com/collections/wands/products/atomic-v-levitat...

It’s basically a shock resistant poly-carbonate tube with a strip of programmable LEDs inside that you spin around for fun. I’m just trying not to shell out $300. It seems simple enough, but this would be my first project of this kind and I’ve quickly found myself out of my depth. WAY out of my depth. I don’t understand the jargon or how to make a proper diagram or anything. But I’m stubborn and I don’t give up easy. My husband told me to find a subreddit so I posted this there. Then it was recommended in a comment to try this forum.

Here’s what I’ve come up with so far (Please see super ghetto unofficial diagram https://imgur.com/a/GBKMZTY ):

A. Power Boost 500 Charger https://www.adafruit.com/product/1944?gclid=Cj0KCQjwm6HaBRCbARIsAFDNK-jJ...

A1. F Micro USB-Power In

A2. F 2 Pin-Power Storage

A3. F USB-Power out

B. Rechargeable 3.7V Battery- https://www.adafruit.com/product/3898

C. M USB to M DC https://www.amazon.com/dp/B00YEI1TG8/?ref=idea_lv_dp_ov_d

D. Mini RF https://www.amazon.com/dp/B01HCHHM04/?ref=idea_lv_dp_ov_d

D1. F DC

D2. M 3 Pin JST-SM

E. LED Strip https://www.amazon.com/dp/B019DYZNU0/?ref=idea_lv_dp_ov_d

E1. F 3 Pin JST-SM

F. Polycarbonate Tubing https://www.amazon.com/dp/B000OMJ578/?ref=idea_lv_dp_ov_d

? 3.7V to 5V Converter? https://www.amazon.com/Converter-Output-Voltage-Step-up-Module/dp/B0183L...

My main concerns are:

I don’t want to start buying things unless I think they’ll work together. Since these are all unfamiliar components to me I have no clue what is compatible with what… or if I’m making this too complicated or not complicated enough.

The LED strip requires a 5V power source and I can only seem to find a 3.7V rechargeable battery pack that will fit inside a 1“diameter tube (I’m willing to compromise on a larger tube but it couldn’t be much larger).

It needs to be an even weight in order to flow properly. It can be slightly heavier on one end if needed. I can weight the other side if it gets too wonky but I’m unsure what would be the best method.

Shock resistant. I’m not going to be beating anyone with this thing, but it needs to be able to handle some sudden stops and drops. I’ll probably end up adhering all of the parts together inside of the tube so nothing is lose in there… but will that make it shock resistant enough?

I’m sure there are unforeseen issues with this design that a more experienced and knowledgeable person will be able to point out! This has turned out to be such a fun challenge-any and ALL help is welcome and appreciated. Smile Thank you for reading and contribulting!

ToyKeeper
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Hi, I’m the same person who answered on your reddit thread. Just commenting here to make sure I get notified about updates and replies. Smile Responses will probably take a while, but hopefully someone can help.

One vaguely similar project here is a lightsaber driver which Texas_Ace designed, and I made some firmware for. It’s not really the same thing, but if you were okay with a single-color wand instead of having pixels, it could perhaps be useful.

I also maintain the community’s firmware repository, and made some of the firmware used in a few products here. But I’m not an electrical engineer so I’m not sure how best to build what you’re trying to make.

At a glance, the design looks physically pretty large for a flow wand. It appears to be lightsaber sized, but flow wands are usually a lot thinner and lighter. So the extra size might make it difficult to use, though it’ll also make the electronics a lot easier.

rudimentaryrobonoids
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Hello again! Thanks for the recommendation. I’ve owned the Atomic wand previously and the poly-tubing they used is the same size as the tubing I posted. It’s definitely one of the heaviest on the market, but usable never the less. This might end up being something I have to invest in-but heck it’d be a lot funner to make my own! Thanks for sharing that thread-I can see where certain elements are similar and can be useful.

I have a little extra cash so I can do some trial and error just to get the ball moving. I’ll be sure to post photos and updates Smile

aginthelaw
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After you complete this project, can you make me a pair of led nunchucks ?

never fear shadows…it means a light shines nearby

Marc E
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From a battery point of view, if you’re going 3.7v li-ion it seems simpler to use an 18650 in a ready made battery tube, of which there are many around 1” diameter, and use an external charger for the charging, again of which there are many.
(Edit: I will post some pics to show you what i mean when i get a chance, taking me longer to find some online than i thought.)

As for the driver, i have no idea! Is the wand you linked to programmable on the fly or can the modes only be changed via a PC?

ToyKeeper
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If I understand correctly, the actual LEDs are controlled via bluetooth. So the driver needs to receive bluetooth data and convert it to something the LED strip can use. It doesn’t need to have the logic and the patterns onboard.

Here’s how that looks during use (pic is from the store in the OP’s link).

Anyway, if you can avoid the need for a boost converter, it’ll make things a lot simpler. Hopefully it can run at 3.7V instead of 5V.

As for the actual battery, pick a tube size, then pick a li-ion cell which fits. For a tube with a 25mm inner diameter, even a relatively large one could fit, like a 21700 cell. And those come in capacities up to 5000 mAh. But an 18650 cell is a lot more common, and capacity runs as high as 3500 mAh in those. Or for a smaller wand, the 14500 size may be good (it’s the same size as an AA battery), and those have around 900 mAh.

For the size I normally associate with flow wands, a tiny 10180 cell is probably more appropriate. Perhaps one in each end, with a driver at each end, controlled independently. One LED shining from each end into a translucent tube. But that won’t do any fancy pixel displays… just a solid color. And nowhere near as bright, or for as long, since the capacity is only like 80 mAh. But it sure is small and lightweight. Smile

For charging the thing, it’s probably a good idea to just put a charge port somewhere which directly exports the + and – ends of the battery. Then hook up a normal charger to it. At least, that’s how I handle charging in a lightsaber. It’s just a common 2.1mm jack and some extra bits to allow me to connect that to a battery charger. The visible “battery” in this picture is just an inert cylinder that I attached wires to. Inside, I have a single 18650 cell plus some electronics to make it light up the blade.

ToyKeeper
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I’m a little surprised people haven’t had more ideas yet.

joechina
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I know this things under the term POV Display.
Googling for: POV and
- make magazin or
- adafruit or
- arduino
should bring a few results.

Our forums light painter Stephenk may know more, just PM him.

Light Painting – Overview from Stephenk
Lightpainting
http://budgetlightforum.com/node/55011

kikkoman
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You can omit the 3.7 to 5V boost converter, the Adafruit thing has everything on board. (You could rip out the circuitry of one of those cheapie powerbanks for a fraction of the cost btw.)
As for running everything directly off a battery, I don’t know. The WS2812 strip and the controller require 5V as per the datasheets, they may or may not work below that.