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RabbitEatsMoon


stranger


Total posts: 10
Posted:I thought I'd resurrect this old topic mainly, I admit, to try to get some information from the trailblazers who have gone before. But perhaps I can add my own pointers also.

I'm looking to build some LED Poi with a microprocessor (probably an Atmel) driving a Luxeon Rebel Endor RGB Star. Cree seem to be a preferred LED manufacturer but finding RGB Cree Stars is more tricky. The power supply will be a couple of AAAs for weight and simplicity reasons. The microprocessor will use PWM to control the three LEDs and mix the colour.

I have previous experience with an ATMega driving an array of 5V LEDs to make a static POV display, but these power-LEDs (Luxeons and Crees) seem to require a whole new circuit design to cope with constant (and high) current.

Most power-LED projects on the Internet advise some sort of an LED Driver to achieve this, which for our 2*AAA (3V) power supply means a "Boost Converter" that boosts the voltage up to that required by the LED, and outputs a constant current. You specify the current at purchase and so can potentially run your LED at a higher current (brighter, but shorter LED life). The consensus seems to be that by _not_ using an LED Driver (or equivalent circuit) then you risk blowing your LED. The only suitable LED driver I have been able to find that takes our 3V input is the LuxDrive MicroPuck (http://www.luxdrive.com/luxdrive-products/micropuck-2009a-single-led-driver/). Luckily a lot of people seem to want to upgrade their torches with high power LEDs, meaning that there is a market for small LED drivers that run off small batteries. I've found various cheap boards from China with various states of documentation that I may try as well, although "cheap" is a relative term for something that fries a 15 LED.

As an aside: LEDSupply (http://ledsupply.com/led-kits.php) do an interesting kit where you specify a single LED (eg a Cree XP-G), a MicroPuck of your desired current, and a battery pack, and free soldering for a very reasonable price. What you therefore have is a very bright torch (139 lumen even), or, to put it in poi terms: the guts of a single colour Hyperlight. Since it seems one of the big attractions of Hyperlights is the sheer brightness of them, I thought this worth mentioning. For some people a pair of very bright white glowing sock poi that you can see in the daytime might be all they need, given the cost and availability of the alternative.

So the MicroPuck is great, but it seems that to use it in an RGB microprocessor controlled poi we would need to have three of them, together with some transistors to switch them on and off with PWM. This concerns me since although these things are tiny, they _do_ have a weight, and a physical size. Not to mention they cost about $10 a pop. So suddenly our two pois are costing maybe $150 in electrical parts alone. And that's a lot for me to smash into a wall in a moment of abandon.

However, I've found a few projects on the Internet, including in this very forum, that seem to go with the old-skool LED approach of sticking a resistor in series with the LED as a method of limiting the current. Everything I've read tells me that this is crazy and just won't work with the power-LEDs, but _if_ it works at all (maybe at a reduced efficiency, increased heat, and shorter battery life) then it would be _far_ lighter and cheaper to use three resistors than three LED Drivers.

I've gone back through the archives and there have been a surprising number of people that have made their own LED poi, and gone through this very design stage. But information is sketchy. Links to promising "open source poi" websites are dead, and circuit diagram images are frustratingly missing.

So, yeah, I'm hoping for some of this lost information to be resurrected. But also on a less selfish note that we can perhaps update the technology that was around 4 or 5 years ago to that of today. Maybe find more creative uses for that accelerometer, add a mic for beat detection, or bluetooth our colour patterns to our pois via a handy iPhone app. smile

I feel that I must point out my interests here. I _totally_ respect Hyperlights. It's mindblowing that they were first mentioned in 2005, and everyone rates them as the best possible LED poi and desperately wants some, mostly going purely on a couple of YouTube videos and some long-exposure photography. The waiting list is (by my estimation) 4 years to get hold of them, and the price has at least doubled. Yet still they are quite simply a huge leap forward from anything else on the market. I rate myself a very novice spinner (think 5BW and a few isolations) who is likely to either brain himself or smash some expensive LED poi, and yet _I'd_ buy Hyperlights for 300 if I could get them tomorrow. But as I can't, I think it would be a great fun project to make my own programmable poi. Sure it's reinventing the wheel, but also I think it would be cooler to show off your super-bright poi and then be able to say that you made them yourself. Anyway, I have no plans to make commercial poi (hell, it's take Hyperlights the last 4 years to get to that point and I don't imagine all of it has been fun), or to undercut or poach sales from anyone else. I just fancy a little side-project that will encourage me to get on with learning some more poi moves in the process.


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Midkiff
BRONZE Member since Nov 2009

shadow stranger
Location: Carmi, Illinois, USA

Total posts: 462
Posted:well i wish you good luck on your ventures and if you find an easy way to do it please share as i would like to know

"Is God willing to prevent evil, but not able? Then he is not omnipotent. Is he able, but not willing? Then he is malevolent. Is he both able, and willing? Then whence cometh evil? Is he neither able nor willing? Then why call him God?" - Epicurus

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RabbitEatsMoon


stranger


Total posts: 10
Posted:Just a quick followup to some useful forums to look at for more information.

http://www.thecustomsabershop.com/
br>- Lightsaber manufacturer and modding. (sadly not real ones) These guys used to use LED strips and even EL-Wire for the blade. Now use Luxeons. Most often seem to use more battery power than we'd want in a poi and hence 'Buck' LED Drivers. A good many people seem happy with a simple resistor setup since (I imagine) they're not so fussed with battery life or performance. Again, from my understanding, to use a resistor setup you'd need to power with more than, say, 3.5V - which means something more than 2*AA / AAA. A lightsaber at it's heart is just a fancy torch, just like an LED poi. One thing though: most lightsabers (if not all) are single colour, so there are no examples of microprocessor control of colour. However, quite often people use RGB LEDs and resistors to create a specific 'blade' colour. And in my mind just getting a circuit to drive the LED is half the battle.

http://www.candlepowerforums.com/
br>- Torch modders. These guys take high-street torches and stuff power-LEDs and drivers into the tiny space that the bulb used to be. Lots mods seem to be for small torches which run off a couple of AA or AAAs, which is great for our pois, weight-wise. People are usually very concerned about performance (heat, battery life and brightness) and so mostly go for LED Drivers. And because there is a market for this, there is a bewildering array of very small LED driver chips and circuits that will fit into the head of a torch. This is perfect for us...once we can find the right one to use. I've got my eye on one that seems perfect in all respects other than it's an unbelievably small SMD chip, and requires even smaller external components to work (I'm talking something that is 1.5mm * 0.8mm and needs two solder connections...) Since all I've done before is some basic DIP soldering - this scares me. smile Luckily these components are pretty cheap so I plan to destroy a few as I go.


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*HyperLight
BRONZE Member since Dec 2003

*HyperLight

old hand
Location: Great Malvern [UK]

Total posts: 1174
Posted:Hehe.. this brings back some memories of some of the things I looked into when I was getting started with Hyperlights.

Looks like you're starting to realise why high-end equipment is so expensive - there's some complicated technology in there. There are shortcuts you can make to get something similar to Hyperlights, but to get a reliable, programmable, and uber-bright LED toy that lasts more than five minutes on AAAs and doesn't start fading when the battery voltage drops is not an easy job!

The cost and limitations of existing glow technology was what drove me to start down the Hyperlight rabbit hole so I wish you the very best of luck. There are thousands of hours of development in what I have now and most of that time has been really interesting. It's definitely worth investing time in a project like this - I've learnt sooo much since I started on the first prototypes! If you think we're using 4-5 year old technology though, you're very wrong; the Hyperlight design has been anything but static. A fair number of the components we now use in the toys weren't available even 2 years ago wink

...and finally, if you're after a pair, I should probably mention we'll have a batch of 50 pairs ready fairly soon. This is the start of us gearing up to make more and more poi so people may have been waiting 5 years for their toys, but the waiting list is going to diminish rapidly over the coming months..

Don't be scared off by SMD components. It's amazing how good you get at solder ~1mm square resistors after the first 10! Just make sure you buy more than you need because even picking them up with tweezers you'll still drop / launch a few into the carpet never to be seen again.

Good luck! grin

EDITED_BY: *HyperLight (1286332998)


Cake or Death?

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happyinmotion
SILVER Member since May 2007

newbie
Location: , New Zealand

Total posts: 42
Posted:Good luck indeed. There's immense potential here now that the tech is getting close to to doing what we'd like it to do. However, yeah, it's hard to get brightness AND long battery life AND durability AND affordability. Still, good to know there's now N+1 people working on it.

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RabbitEatsMoon


stranger


Total posts: 10
Posted:A fun link I stumbled on today setting the goalposts higher. I'm sure you can imagine the possibilities in the technology for poi.

http://appadvice.com/appnn/2010/10/led-lights-control-wifi-connection/


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RabbitEatsMoon


stranger


Total posts: 10
Posted:Just wanted to post a follow-up to my earlier rambling to say that "torches in sock" poi are really fun and simple to make. Commercial torches are not so good because ones of the correct dimensions (flat and round) use bog-standard LEDs which are too dim, so you have to roll your own from super-bright LEDs, as I mentioned in a previous post.

I finally got round to assembling mine, using a Cree LED and Micro-Puck, driven by 2 AAAs. I say "assemble" - mostly this involved metal spice pots I found in the house, packing foam, and lots of gaffer tape. smile For an initial experiment I was interested to see how well the sock lit up, so I bodged the components into a case, taped it all up, and was pleasantly surprised.

Of course there's quite a leap from sticking the guts of a torch in a sock to designing a circuit with a micro-controller PWM driving an RBG LED (and everything else on your personal wish-list), but this is a simple diversion while you're waiting for that next batch of Hyperlights to become available.

And, I emphasise again, just having a pair of static white glowing sock-poi is really fun!


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JaredW
SILVER Member since Oct 2009

JaredW

enthusiast
Location: Flying south for the winter., ...

Total posts: 375
Posted:Rabbit, are you on Facebook?
There's a poi hardware group started by Drex, there was quite a bit of discussion on making LED poi in there. One topic actually got big enough they split off and started another group specifically for people working on poi to share information.

It's a closed group to keep it all on topic, and easy to find info, but just ask about it on the poi hardware form and I'm sure somebody there can point you to it.


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RabbitEatsMoon


stranger


Total posts: 10
Posted:Thanks for that, Jared. Although I don't have a Facebook account. smile

I got as far as ordering a few hundred dollars of components on this (taking the huge Customs and FedEx charges of importing to the UK), made some pretty cool bright white pois with 2 overdriven Crees in each. Very easy to buy/make as detailed above, brighter than any RGB LED (I think - certainly the power makes a couple of AAAs nice and toasty), and quite fun. As I said before, half the attraction is in having brightly lit sock poi at night. RGB LEDs would be nice too, of course, but I think would involve a whole lot more R&D, a much more complex circuit, and not to mention a lot more individual shipping and Customs fees.

I can tell anyone interested though that when you factor in the cost of the LED, driver circuit, heatsink, microprocessor and programmer, casing, various epoxy resins, international shipping and so on... you are talking about a quite considerable cost for components alone. And that's without the cost of time to build them. So although the prices being quoted for commercial pois of this sort seem expensive - they're really not.

If, of course, you could actually buy them and/or receive the delivery. smile


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*UltraPoi*
GOLD Member since Feb 2007

*UltraPoi*

Ultrapoi.com
Location: Texas, USA

Total posts: 49
Posted:Amen to that Rabbit, If you ever decide to go further let me know if you need any advice on the technical side of things.

<br />Ultra Poi, LLC<br />Member

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Udo_Rabe
SILVER Member since Feb 2010

Udo_Rabe

stranger
Location: Germany, Bayern, Grfenberg

Total posts: 2
Posted:Hi Rabit,
how is your project going?

I started a project as well some 3 month ago.
What still drives me cracy is the housing for the self-made POI and the question how to fix the battery.

I use a PolyCarbonat tube - which still can break !
The electronic set-up seems to work so far:
- battery charger circuit
- one switch
- atmega C
- resistors for the LEDs
- usb port (charging an ISP programming)
- freeware program for programming
- self developed PCB board
- PC tube for the housing

-> I will remove the currently used power booster chip when using LiPo batteries in the next version as the power booster chip draws to much current off the nimh battery even when the POI is off.

Programming seems to be challanging:
- faing is not easy
- colour mixing for RGB seems to be fun
but I am progressing
-> Currently I have 6 modes that can be toggled by the switch

Of course HyperLight is right:
- it is challenging
- it is not easy (you need quite some time)
- you have to spend some mony to get something that is usable and will not break on the fist hit

But I am sure you/we can do it...


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RabbitEatsMoon


stranger


Total posts: 10
Posted:Well thankfully for the sake of my real work I sort of lost the urge to make these things. smile It's still a cool "art" project, should you want to persevere, and I don't see any sign of a commercial alternative (STILL!), so merely owning something that flashes still has street-cred.

It'll certainly cost a few hundreds of dollars, months of time, and a lot of trial and error. But like any art project, that's half of the point in doing it.

Parts are not cheap, so even a mass market commercial product (and I mean by that something made in bulk, available from multiple online outlets, and _available_ smile ) is not going to ever be bought for pocket money.


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*UltraPoi*
GOLD Member since Feb 2007

*UltraPoi*

Ultrapoi.com
Location: Texas, USA

Total posts: 49
Posted:Hey guys,

There is still hope! Ultra Poi is on track for a "real" summer release of our poi as well as a couple other items of LED gear. We want to kill the stigma of pro LED Poi being unobtainable/break the bank expensive. Check our videos to get a good feel of what ultra poi has got, we are dealing with some really awesome modes and some serious pulse width modulation. If you want any more information visit Ultrapoi.com and join the ultra poi presale list or shoot us an email at ultrapoillc@gmai.com


<br />Ultra Poi, LLC<br />Member

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Jameth
GOLD Member since May 2008

Jameth

enthusiast
Location: NSW, Australia

Total posts: 378
Posted:I'm going to hold out for the final version of your pixel poi.

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2346


stranger


Total posts: 1
Posted:Originally Posted By: happyinmotionGood luck indeed.
flexible led strip lighting There's immense potential here now that the tech is getting close to to doing what we'd like it to do. However, yeah,led outdoor lighting fixtures it's hard to get brightness AND long battery life AND durability AND affordability. Still,mini led light bars
good to know there's now N+1 people working on it.


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