entry level lights to see by

On 04/01/13 12:30, datakoll wrote:
On Thursday, January 3, 2013 8:11:22 PM UTC-5, James wrote:
On 04/01/13 10:59, datakoll wrote:

OK OK but how goes the costs comparisons to commercial systems analagous to what yawl put together ?



How hard would it be to leave at least the person's name to whom you're

responding in your reply?



From a reputable (??) supplier, about $7.24 per CREE XR-E that comes

mounted on an aluminium base.



http://www.digikey.com/product-detai...TAR-ND/2360955



(You can likely find a cheaper source, and there are cheaper copies

available, but they may not be up to spec.)



I used 4 of these, so about $30.



Lenses range in price from about $1.60 to $3.20 or so. I don't recall

which ones I got off hand, but let's say the lenses cost me about $15.



I mounted the LEDs on a piece of Al angle that I had in a scrap bin -

cost nothing.



I have wire, solder and an iron to wire them together - cost nothing.



I reused and slightly modified an old bike light mount to attach the Al

angle to my handlebars - cost nothing.



The dynamo was in my old parts box - cost nothing.



So for $45 I got a dynamo powered LED headlight that has been used

through cold, wet, dirty, hot and dry conditions for about a year already.



I never have to recharge it or buy batteries for it. Just eat breakfast

and drink coffee ;-)



The heatsink does not get hot, in fact it barely gets warm. Why?

Largish piece of Al that is in the air flow and only dissipating 3W or

so when you're moving.



Even when I've tested it riding on rollers on a winters night, at 60

km/h for long periods (compared to the heating time constant of the Al),

the heatsink only got warm - I'd guess 25 - 35 degrees C at most.



--

JS.

.......


DEAR ALVA,

and the price of a comparable commercial rig ? I imagine the various control components are nickle and dime. So what did your dyno cost.

Usually when I plan DIY projects I may see a 40% savings in parts over commercial but yawl go bonkers with these LED DIYs.

Off course when i add in the commericla labor costs the savings goes waaaay over into big green,

Bartfarst

The Google King is asking _me_ to search for a comparable commercial rig?

*IF* you include the dynamo, I guess a few hundred bucks.

--
JS.

wrote:
:On Thursday, January 3, 2013 4:53:47 PM UTC-5, David Scheidt wrote:
: Frank Krygowski wrote:
:
:
:
:
:
: ptics, too.) The taillight is actually _too_ bright, so I plan to
:
:
:
: Not likely. A bog standard automotive taillight bulb outputs 300
:
: lumens. Cars have at least two of them, and pretty good optics
:
: pointing backwards, and they're still hard to see in fog or other bad
:
: visibility conditions. I'll bet quite a lot that you don't have
:
: anything approaching that. Observers telling you anyting at all is
:
: totally without merit. Get a meter, tell me that at useful distances
:
: and angles, then I might believe.

:I'm basing my evaluation on observing the light myself. Sorry I can't

Eyes are horrible observers of lighting, because they and the brain
they're attach to adapt to different situations, and it's very, very
hard (and often physiologically impossilbe) to put object rankings
down correctly. So in a very dark situation, you can be be blinded by
a not terribly bright bit of light, particularly one that's narrow
angle (bad optics!). But in real world traffic situations, you might
even be able to see that same source over the background clutter.

: tell you the model of LED (it was given to me by an LED product engineer)
:but I judged it to be blinding. Your evaluation may be different, but it
:might be wise to wait until you have a chance to actually see my bike at
:night!

A motorbike is displaying at least 300 lumens to rear. If you've got
less than that, making it dimmer is the wrong solution. It might be
the easiest, but it's not the safest. it's much better to use some
optics to more appropriately direct the rathe meager number of photons
you're shedding somewhere they can do you good.


:
:
: If you want to be dumb, sure.

:You mean, evaluating my design based on actual observation?

I see no reliable observation reported.

--
This is not a randomly numbered sig.

Jeff Liebermann wrote:

:Personally, I think the whole dynamo power LED light is done wrong and
:reeks of ultra conservative design. The dynamos were originally
:designed to power incandescent 6V lamps, which they do reasonably
:well. The voltage and power output nicely match several 6V 0.2A bulbs
:in parallel. However, nobody but kids and department store bicycle
:shoppers buy incandescent bicycle lamps these daze. Time to
:re-examine the assumptions.

:The requirements for running a 2 watt LED are quite different. It
:needs brightness regulation, dimming, and flashing. The circuitry
:needed to do all this is inherently lossy when running a low voltages.
:The solution is to build a dynamo that produces more voltage and less
:current at the same power level. For the 3 watts, instead of 6V at
:0.5A, it should produce 24V at 0.125A. This would go to a DC to DC
:inverter to run the LED. While the forward voltage drop of the bridge
:rectifier and saturation voltages of the switching components
:contribute substantial losses in a low voltage system, they are far
:less significant in a higher voltage system. If you want efficiency,
:you need higher voltages. (As an added bonus, the copper losses in
:the wiring will be less with higher voltages).

In another post, I posted a link to the disassembly of a B+M Cyo (if
you're not familiar, it's the bottom of high end lights. It's about
100 bucks US retail.) It's just pictures (the website is german, there
may a forum post about it somewhere with some text, but since it's
likelyt to be in german, itwouldtn' do me much good), but there are
some shots that show the circuitry. It's a lot more complicated than
you'd expect, I'd think (it's more than I expected, and I've got one.)


--
sig 27

Lou Holtman writes:

Op 30-12-2012 7:22, Phil W Lee schreef:
Sir Ridesalot considered Sat, 29 Dec 2012
17:59:55 -0800 (PST) the perfect time to write:

[ ... ]
The advantage of Dan' lights is that they are easily transferred to different bikes.

So is the Busch and Muller Ixon IQ, which runs on 4 x AA NiMH cells,
and gives 5 hours on high (only necessary of unlit roads),

That is another marketing 'lie'. I have one and it runs max 2 hours on
high of which the last half an hour dangerously low for unlit
roads. Again I was disappointed in the battery life of a battery
powered light. Plenty of light but only for a short period of time
that is the deal. Charge before every ride, that sucks for me.

I concur -- when using the battery operated version with NiMH cells
two hours on high was the most I could manage.


--

SMS wrote:
Quite rare around here to see a cyclist with lights where the
front light is not a strobe.

Strobes are illegal in Germany, which happens to have a rather high
density of day and night bicycle traffic and no reasons to advocate
or allow strobes, thank you very much.


The increase in the cyclists daytime visibility is incredible.

Yes, incredible irrelevant.


--
Best regards
helmut springer panta rhei

On Jan 4, 8:30*am, Helmut Springer wrote:
SMS wrote:
Quite rare around here to see a cyclist with lights where the
front light is not a strobe.

Strobes are illegal in Germany, which happens to have a rather high
density of day and night bicycle traffic and no reasons to advocate
or allow strobes, thank you very much.

The increase in the cyclists daytime visibility is incredible.

Yes, incredible irrelevant.

I'm not an advocate of daytime strobes, but they do make cyclists more
visible on gloomy/stormy winter days here in PDX. Bright colored
jackets also work well -- which is my preference.
http://www.flickr.com/photos/cmkeiner/6697564547/

-- Jay Beattie.

On Jan 3, 1:01*am, Phil W Lee wrote:
James considered Thu, 03 Jan 2013 09:21:05
+1100 the perfect time to write:









On 02/01/13 17:01, Phil W Lee wrote:
*considered Wed, 02 Jan 2013 08:06:14
+1100 the perfect time to write:

On 01/01/13 05:33, Phil W Lee wrote:
* considered Mon, 31 Dec 2012 09:17:17
-0800 the perfect time to write:

* * * * With LED lamps things have improved somewhat since as long as the
LED lamp has sufficient thermal dissipation you can run it at higher
voltages without incident.

It's even better than that, actually - both LEDs and dynamos are
constant current devices, so they match each other perfectly, once you
rectify the AC dynamo output to a DC LED input.

Better still, with multiple LEDs (2, 4, or 6 depending on their
electrical ratings), it is entirely feasible to rectify the AC *using*
the LEDs themselves, thereby eliminating any losses attributed to
rectifiers - which can be substantial unless a hybrid MOSFET rectifier
is used.

My headlight uses 4 CREE LEDs. *Each has a forward voltage drop of about
3.? volts, and can withstand 5 volts in reverse. *It has been in
operation now for over a year now with zero defects, several
compliments, and was mistaken by a policeman as an approaching motorbike!

The downside of multiple LEDs is that none of them will be at the
focal point of the reflector/lens assembly, unless you duplicate all
the optics as well - which are the most expensive parts of the light.

$8 ea from the local supply shop is not budget breaking, and I'm sure
they're available cheaper elsewhere.

To road vehicle lighting standards?
I'd find that rather surprising.



So great if you just want to increase the light output, but not so
great if you want to retain some control over where it goes (which
many jurisdictions insist on, including the one I happen to be in).

Well, as I said to Frank, I like side spill. *The beam patterns I saw on
Peter White's site didn't inspire me much that they were wide enough,
nor high enough to read street signs.

You can't tell much from a photograph - the human eye responds
differently to light.
The people who've actually used them tend to keep on using them, which
is the best recommendation I can think of.
The overwhelming majority of the critics seem to be people who have
not, and refuse to even entertain the idea.

Cycling is full of impressionable fashion victims to whom every BUMM
lamp is the the greatest lamp ever — until the next one comes out. The
Cyo could be due for a fall in esteem when the Luxos gets some more
exposure.

So Phil is partially right. But there are quite a few people, me
included, who are longtime BUMM lamp users, and also critics of the
most stupid of the German laws, which often have a negative effect on
the lamps we all use, and of the physical manifestations of BUMM's
roadie pretentions, among them the focus (heh-heh) on throwing the
light a long way up the road instead of in front of the wheel (not so
bad now that there is lots of light to play with) and to the sides, so
that the 97% of users who aren't riding at 30mph can also see.

Andre Jute

On Jan 4, 1:11*am, James wrote:
On 04/01/13 10:59, datakoll wrote:

OK OK but how goes the costs comparisons to commercial systems analagous to what yawl put together ?

How hard would it be to leave at least the person's name to whom you're
responding in your reply?

*From a reputable (??) supplier, about $7.24 per CREE XR-E that comes
mounted on an aluminium base.

http://www.digikey.com/product-detai...-00D02-STAR/XR...

(You can likely find a cheaper source, and there are cheaper copies
available, but they may not be up to spec.)

I used 4 of these, so about $30.

Lenses range in price from about $1.60 to $3.20 or so. *I don't recall
which ones I got off hand, but let's say the lenses cost me about $15.

I mounted the LEDs on a piece of Al angle that I had in a scrap bin -
cost nothing.

I have wire, solder and an iron to wire them together - cost nothing.

I reused and slightly modified an old bike light mount to attach the Al
angle to my handlebars - cost nothing.

The dynamo was in my old parts box - cost nothing.

So for $45 I got a dynamo powered LED headlight that has been used
through cold, wet, dirty, hot and dry conditions for about a year already..

I never have to recharge it or buy batteries for it. *Just eat breakfast
and drink coffee ;-)

The heatsink does not get hot, in fact it barely gets warm. *Why?
Largish piece of Al that is in the air flow and only dissipating 3W or
so when you're moving.

Even when I've tested it riding on rollers on a winters night, at 60
km/h for long periods (compared to the heating time constant of the Al),
the heatsink only got warm - I'd guess 25 - 35 degrees C at most.

--
JS.

Back when I first built my own lights, it was still in the Days of
Halogen. They put out quite a bit of heat. I glued the MR11 and MR16
shells and glass I was using for the good optics into small Roma
tomato puree tins, and never noticed them getting unduly hot, as long
as the bike was moving. That's good enough for me. (I did actually
have a meter on it for a while, but I could have eyeballed it with my
fingertips, to mix a metaphor; total waste of time fixing the meter so
it wasn't dropped and damaged.)

Andre Jute

David Scheidt wrote:
Frank Krygowski wrote:

ptics, too.) The taillight is actually _too_ bright

Not likely. A bog standard automotive taillight bulb outputs 300

- white, unfiltered source ones, presumably, maybe 1/4th of them "red" -

lumens. Cars have at least two of them, and pretty good optics
pointing backwards, and they're still hard to see in fog or other bad
visibility conditions. I'll bet quite a lot that you don't have
anything approaching that. Observers telling you anyting at all is
totally without merit. Get a meter, tell me that at useful distances
and angles, then I might believe.

He's obviously talking about excessive luminance. Do try leaving the
extravagant ignorance to sms.

On Jan 4, 3:37*am, David Scheidt wrote:
wrote:

:On Thursday, January 3, 2013 4:53:47 PM UTC-5, David Scheidt wrote::

A motorbike is displaying at least 300 lumens to rear. *If you've got
less than that, making it dimmer is the wrong solution. *It might be
the easiest, but it's not the safest. *it's much better to use some
optics to more appropriately direct the rathe meager number of photons
you're shedding somewhere they can do you good.

What I actually did with that taillight on that 3 speed was to angle
it downward by bending its mounting bracket. (It's mounted at saddle
height.) There was no electrical penalty in doing so. I did it simply
because I really did judge the light to be blinding to anyone behind
me.



:
:
: If you want to be dumb, sure.

:You mean, evaluating my design based on actual observation?

I see no reliable observation reported.

Well, I didn't see any need for formal documentation, especially since
I can't even tell you the model of LED I'm using. Again, it was given
to me (with its heat sink and a nice constant current source for bench
testing) from the spare parts box of an LED engineer.

What I can say is that this LED is FAR brighter than any other bike
taillight I have. And as I've reported here many times, not only have
I never experienced a conspicuity problem at night, I've even gotten
many spontaneous compliments on my light and reflector setups.

BTW, this particular 3 speed bike generated a rather nice spontaneous
compliment last winter. I serve on a certain local committee, and one
woman who's also on that committee asked me at a meeting "Was that you
on that bike with those space shippy lights? [her words.] That was
really impressive!"

I'm not trying for "space shippy" whatever that is. I figure as long
as I'm noticed at night as readily as in daytime, I'm fine. And I
think I exceed that by a nice margin.

--------------------

I probably shouldn't mention this, but this summer I crammed another
LED from the same source into another old taillight, to be driven by
my utility bike's Shimano hub generator, the bike with the B&M Cyo.
When I hooked it to the output terminals on the Cyo, the taillight
was, again, blinding, but I was disappointed to see the Cyo get much
dimmer. Some trial and error showed that about 33 Ohms in series with
the taillight returned the Cyo to full brightness, and the formerly
blinding taillight on _that_ bike was still much brighter than the
battery blinky I'd been using (and still have mounted).

- Frank Krygowski