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Forums > Technical Discussion > Ideas on how to mount/arrange LEDs

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The Misguided Oracle
GOLD Member since Aug 2005

The Misguided Oracle

the floor is a sea of tigers...
Location: Brisvegas

Total posts: 404
Posted:Just wondering if anyone has any ideas on something that has been bugging me for quite a while. I'm was trying to find a way of putting x number of LEDs in column kinda like an LED strip, but i need the light to shine in all directions (not just from the top of the board) & for each LED to be controlled seperately. (this will eventually be mounted on a staff and/or poi)

I've though of soldering wires to them & then sticking them into a transprent tube & progressively filling it with either hot glue or silicone, but the problem with that is I'll probably loose the "pixel seperation" between a lit & unlit led. And also I haven't figured out a way that'll deal with the "shadows" that'd be caused by the wires.

Another idea which I'm leaning towards at the moment is using surface mount LEDs on both sides of the board. From what i've been reading, soldering surface mount components isn't as hard & expensive as everyone else seem to make it out to be. however this would mean that I'd be using double the number of LEDs = higher cost & lower battery life...

I don't think arranging 3,4 or more LEDs around the staff would help much either...

I think there might be some glow toys that do that on a smaller scale, but I haven't started amassing a collection yet (not that i have that much spare cash lying around)... so if anyone has any ideas plese do share. or if one of your glow toys seem to resemble what I'm trying to do, please do tell (and maybe a pic or 2 smile )

Thanks!


"My body is a well tuned machine... It just needs a competent driver." - ?

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polarity
SILVER Member since May 2005

polarity

veteran
Location: on the wrong planet

Total posts: 1228
Posted:My current mountings for poi have the LEDs mounted pointing up towards the handles, which works OK as the LEDs have a 140deg viewing angle. There are 12 wires running past the bottom LED though, using 4 LEDs and two control buttons on the handle. Shadows aren't noticable, firstly because the cases are sanded on the outside to diffuse the light, and secondly because the LEDs are so bright.

If you run the wires as far as possible from the LEDs, up the inside of the casing, it reduces the angle that they obscure. The metal cages on my first prototypes were used partly for this reason, but the wires ran up the outsides.

The next prototypes (more like stick poi/fire swords in polycarbonate tubes) are going to have LEDs mounted on 3 long strips of circuit board, so they can be wrapped around a central core of wires, and have a full 360deg viewing angle and no shadows. I'm looking at having 32 rings of 3 LEDs, and was thinking of putting the transistors/resistors and shift registers on another board behind groups of 8 rings. By putting the shift registers closer to the LED groups I can cut down on the huge number of wires that all meet up at the PIC, and I could also make the design more modular, adding more 8 long LED strips if I wanted to make longer staffs.

Another alternative I've come up with is to make the rings from EL string, taking a wooden dowel as the core of the strip, cutting a groove down one side for the power wires, and wrapping EL string around the dowel to make rings of light. Using that method would give a very high resolution if needed.


I don't like sealing everything in, as there are a huge number of connections that can break, and digging them out of hot melt or silicone is a real pain when it comes to fixing broken connections. Instead I just put hot melt over the soldered joints, so the strain is put on the wire sleeve, instead of the wire core, and I always make sure there is enough slack in the wires. I use teflon coated 7 core wire, which has good flexibility, doesn't stretch, and doesn't melt and creep back from soldered ends. The downside is that it's hard to strip, as it's quite slippy. I'll be getting automatic wire strippers if I start using EL string though.


You aren't thinking or really existing unless you're willing to risk even your own sanity in the judgment of your existence.

Green peppers, lime pickle and whole-grain mustard = best sandwich filling.

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The_Magnesium_Master


journeyman
Location: Brisbane, Queensland,

Total posts: 97
Posted:The best solution is to hope someone brings out a factory produced device with small surface mount components and a fancy IC to run them. Constructing LED gear sux if you want it bright (ie Luxeon LED with up to 1 amp of current per LED) or multi LED equiped. If you still want to continue try and adapt christmas lights or something already miniturised into your device, forget trying to do it from scrach as it probably wont fit into a twirlable item.

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*HyperLight
BRONZE Member since Dec 2003

*HyperLight

old hand
Location: Great Malvern [UK]

Total posts: 1174
Posted:That's a very defeatest attitude! Just because it hasn't been done before most certainly does not mean it can't be done smile

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polarity
SILVER Member since May 2005

polarity

veteran
Location: on the wrong planet

Total posts: 1228
Posted:I'd say it has been done already. I've seen plenty of other designs using high brightness and multiple LEDs, and while they may weigh more than sock poi, they're certainly no heavier than fire poi, and the same can be said for staffs.

My own design is very lightweight, and still manages 2 hours use with 4 X 3W RGB Luxeons.

With a single RGB Luxeon the design is about twice as wide as a glowstick, and half as long.


You aren't thinking or really existing unless you're willing to risk even your own sanity in the judgment of your existence.

Green peppers, lime pickle and whole-grain mustard = best sandwich filling.

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*HyperLight
BRONZE Member since Dec 2003

*HyperLight

old hand
Location: Great Malvern [UK]

Total posts: 1174
Posted:you could probably fit it in a glowstick tbh.. just takes some very clever circuitry!

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The Misguided Oracle
GOLD Member since Aug 2005

The Misguided Oracle

the floor is a sea of tigers...
Location: Brisvegas

Total posts: 404
Posted:ooo Polarity, 3x32 RGB LEDs is gonna be exxie$$$

anyway, in your 1st reply, when you were talking about how your leds were mounted, they are all not on the same pcb right? I can't seem to access your site to look at piccies of your glow poi

Written by: *HyperLight

you could probably fit it in a glowstick tbh.. just takes some very clever circuitry!


and probably surface mount components smile
or if you aim to fit it into a 15" glowstick wink

ooo, I also think I might have found a way to dectect hand positions (can be one or 2 hands) along the whole length of a staff without funky gloves and what not... I bet if that could be used for something nifty...


"My body is a well tuned machine... It just needs a competent driver." - ?

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polarity
SILVER Member since May 2005

polarity

veteran
Location: on the wrong planet

Total posts: 1228
Posted:My webserver is playing up again, and we're moving house soon, so I don't have time / can't be bothered to fix it. May be working again in a couple of weeks, as it's one of the first things I'll be doing once ADSL is available at the new house.

I don't use PCBs at all, they just add to the weight and size, although with surface mount things might be different.

The Luxeons (clones as Luxeon don't do RGB in a single LED) are just mounted on heatsinks, and are pretty much floating in polycarbonate tubes, only held in place by a couple of pins above and the mountings for the chains below. The star shaped baseplate of the Luxeons has 6 slots around the edge, two for screws and another two are over holes in the heatsinks for the wires to go through.

The chip has 12 transistors and 24 resistors glued on top of it, and fits in about the same space as an LED/heatsink assembly. Funny thing is, the heatsinks aren't even necessary, and they're the biggest parts.

The whole design is a lot like a fire poi, with 4 wicks (LED/heatsinks) mounted on a chain. The bottom one just has the chip/transistor/resistor 'lump' and a battery, so it's about 3 times as long as the others.


12v camera battery (1/2AA size) or button cells
1 X 18pin DIP
3 X TO92 transistors
6 X resistors
2 X RGB Prolights (Luxeon clones) with stars removed
2 X new heatsinks to fit tube
1 X standard glowstick case, with some holes for airflow.
solder and wire to connect everything
hot melt glue to insulate joints and stop everything falling apart


The 3x32 LEDs (thats 192 for a pair) shouldn't be too much (SuperFluxes at 85p each) considering how much better they'd look than Aerotechs. I spent 85 on 10 RGB Prolights already. My total for tools, parts and equipment is over 500.


You aren't thinking or really existing unless you're willing to risk even your own sanity in the judgment of your existence.

Green peppers, lime pickle and whole-grain mustard = best sandwich filling.

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The_Magnesium_Master


journeyman
Location: Brisbane, Queensland,

Total posts: 97
Posted:To run 3W Luxeons at anything like full power you do need a heatsink. I used a ground down tap washer soldered to about 100mm of 19mm copper pipe glued into the aluminium centre of my staff, and they run at at least 40degrees above ambient temperature at around 750mA, although they also have a resistor around 2-2.5 ohms to cool aswell.



To maintain distinct coloured sections should be easy if you put a black cardboard or relfective foil spacer between each one. Alternatively use a strip of white cutting board about 10-13mm square and mount LEDs shining into the side of this strip as a diffusing mechanism. The light only scatters about 20-30mm , most of it less than 15mm, so pixel separation will be maintained by keeping LEDs 30mm apart



I made a 12 LED light head with flat pcb mount LEDs drilled into a strip of white cutting board plastic but they were mostly in series, not 13 wires as 12 individually switched LEDs will need.These will bunch up when you try to get them into a tube if the clearance is not far greater than visual inspection would lead you to think will fit.



If you realy want to continue with this I sugest a metal tubed staff with ends at least 50mm diameter to fit the electrics into, and probably do it by setting the light head up in a mould then epoxy filling it. Use rechargable batteries so you dont have to have acess to them over the life of the device.



I deffinitly stand by my recommendation to avoid making this from scratch, and I can guarentee it will cause much frustration if you want it small, narrow and easy to insert into a tube.


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The Misguided Oracle
GOLD Member since Aug 2005

The Misguided Oracle

the floor is a sea of tigers...
Location: Brisvegas

Total posts: 404
Posted:Written by: The_Magnesium_Master

I deffinitly stand by my recommendation to avoid making this from scratch, and I can guarentee it will cause much frustration if you want it small, narrow and easy to insert into a tube.


Ah, but some people do get their jollies from making things from scratch anyway (dispite the effort and occasional fustration) smile


"My body is a well tuned machine... It just needs a competent driver." - ?

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polarity
SILVER Member since May 2005

polarity

veteran
Location: on the wrong planet

Total posts: 1228
Posted:Some of us are just nuts ubbloco

You aren't thinking or really existing unless you're willing to risk even your own sanity in the judgment of your existence.

Green peppers, lime pickle and whole-grain mustard = best sandwich filling.

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*HyperLight
BRONZE Member since Dec 2003

*HyperLight

old hand
Location: Great Malvern [UK]

Total posts: 1174
Posted:Some of us have too much time on our hands *looks at polarity* wink 'tis a lot of fun building things (HyperLights for example).. I just wish I had more time to play with the desgin - stupid job! frown

Cake or Death?

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UCOF
SILVER Member since Apr 2002

UCOF

Carpal \'Tunnel


Total posts: 15414
Posted:I wear my pants on my head.
This sekam me lamron.

smile


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*HyperLight
BRONZE Member since Dec 2003

*HyperLight

old hand
Location: Great Malvern [UK]

Total posts: 1174
Posted:Only if they're inside out though! ubbrollsmile

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solar_bear
SILVER Member since Feb 2006

solar_bear

journeyman
Location: Kent, UK

Total posts: 78
Posted:I can highly recommend the following forum for anybody seriously interested in working with LEDs...



CandlePowerForums A US forum for torch / flashlight collectors, with a lot of in-depth technical knowledge on LEDs and electronics.



In particular, have a look at...

Homemade and Modified Lights

Materials / Mechanical / Mechining

Electrolumiescent / Headlamps / Hybrids

Flashlight Electronics - Batteries Included

LED (this mainly about torches)

Lasers


It may stop, but it never ends.

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The Misguided Oracle
GOLD Member since Aug 2005

The Misguided Oracle

the floor is a sea of tigers...
Location: Brisvegas

Total posts: 404
Posted:wow! lots of info for me to look though.
thanks for that site solar_bear!


"My body is a well tuned machine... It just needs a competent driver." - ?

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daize
SILVER Member since Dec 2005

daize

member
Location: Falmouth, Cornwall

Total posts: 175
Posted:Yeah, cheer for the links. I'm in the process of making some LED poi's as I'm not so keen of the ones on the market. The hardest part was finding some sort of casing to hold the LED's and circuitry. I'm trying out a couple of weird cat toys for my first prototype...Though I don't suppose I'll get it right first time.

Thanks again for the useful info biggrin
Sam cool


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solar_bear
SILVER Member since Feb 2006

solar_bear

journeyman
Location: Kent, UK

Total posts: 78
Posted:You're welcome smile

FWIW here's a couple more...

Don Klipstein's LED Main Page
featuring...
LEDs 101 - basic electronics
LED resistor calculator page The LED FAQ Pages

The LED Center
featuring...
Another resistance calculator
LED array design wizard
Another forum

The LED Museum


It may stop, but it never ends.

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