Coil Powered Spoke Mounted Light

bret

the geek-factor of this experiment is cool. but how practical is it?

for $4.99, you can buy a good little blinky from nashbar

nashbar.comprofile.cfmOpen ↗
&estoreid=

and have something light, reliable and waterproof. weight for weight, it's also going to be better
than the coil & magnet solution. i'm sure that with a little enginuity, you could spoke-mount these
like reflectors and have yourself a lightweight reliable solution with very little bother.

if you still want to experiment, i suggest checking into led driver circuitry. led's by themselves
consume a small, but appreciable current. drivers pulse the current to reduce overall current
consumption - to the human eye, the led /looks/ continuously lit, but isn't. and reduced consumption
means less generation capacity is required.

on the subject of generators, if you want to build your own, you're probably better off winding your
own coils than using some lumping great non-specific piece of kit you bought on sale. to make the
generator as efficient as possible, you need to have the coils and the magnetic fields with which
they interact set so that you have the maximum magnetic field for the maximum time for each pass of
a coil. maximizing the magnetic flux means shaped magnets and tight clearance. similrly, this will
also mean shaped coils.

by the time you're done, to be honest, you'll probably end up with something looking too close to a
dynamo hub to be worth the effort. again, this is not dismissing the value of the experiment, just a
comment on the effort/cost equation.

good luck

jb

jim beam <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

bret

the geek-factor of this experiment is cool. but how practical is it?

for $4.99, you can buy a good little blinky from nashbar

nashbar.comprofile.cfmOpen ↗
ku=8686&storetype=&estoreid=

and have something light, reliable and waterproof. weight for weight, it's also going to be better
than the coil & magnet solution. i'm sure that with a little enginuity, you could spoke-mount
these like reflectors and have yourself a lightweight reliable solution with very little bother.

if you still want to experiment, i suggest checking into led driver circuitry. led's by themselves
consume a small, but appreciable current. drivers pulse the current to reduce overall current
consumption - to the human eye, the led /looks/ continuously lit, but isn't. and reduced
consumption means less generation capacity is required.

on the subject of generators, if you want to build your own, you're probably better off winding
your own coils than using some lumping great non-specific piece of kit you bought on sale. to make
the generator as efficient as possible, you need to have the coils and the magnetic fields with
which they interact set so that you have the maximum magnetic field for the maximum time for each
pass of a coil. maximizing the magnetic flux means shaped magnets and tight clearance. similrly,
this will also mean shaped coils.

by the time you're done, to be honest, you'll probably end up with something looking too close to
a dynamo hub to be worth the effort. again, this is not dismissing the value of the experiment,
just a comment on the effort/cost equation.

good luck

jb

I found a neat little gadget called tireflys. Sold in a 2-pack for around $7, they're little
watertight capsules that contain a blinking LED, powered off three pocket calculator button cells,
and screw onto the valve stem. Works fine for car type valves, havn't tried them on prestas. A
simple vibrating spring motion sensor activates them when the wheels spin. On the ones I have, the
sensor wasn't sensetive enough, but tweaking it wasn't too much trouble. They come in many colors,
including a multicolor type. For practical reasons, I chose amber.

"Traveller v.116" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I found a neat little gadget called tireflys. Sold in a 2-pack for around $7, they're little
watertight capsules that contain a blinking LED, powered off three pocket calculator button cells,

and

Quoted message said:

screw onto the valve stem. Works fine for car type valves, havn't tried

them

Quoted message said:

on prestas. A simple vibrating spring motion sensor activates them when

the

Quoted message said:

wheels spin. On the ones I have, the sensor wasn't sensetive enough, but tweaking it wasn't too
much trouble. They come in many colors, including a multicolor type. For practical

reasons,

Quoted message said:

I chose amber.

Those look pretty neat. Do they come with a presta adapter, or do you have to fudge something?

--Josh

"Josh Gatts" <[email hidden]> wrote in
:"]news:[email hidden]:

Quoted message said:

"Traveller v.116" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I found a neat little gadget called tireflys. Sold in a 2-pack for around $7, they're
little watertight capsules that contain a blinking LED, powered off three pocket calculator
button cells,

and

Quoted message said:

screw onto the valve stem. Works fine for car type valves, havn't tried

them

Quoted message said:

on prestas. A simple vibrating spring motion sensor activates them when

the

Quoted message said:

wheels spin. On the ones I have, the sensor wasn't sensetive enough, but tweaking it wasn't too
much trouble. They come in many colors, including a multicolor type. For practical

reasons,

Quoted message said:

I chose amber.

Those look pretty neat. Do they come with a presta adapter, or do you have to fudge something?

--Josh

As far as I know, there's no presta adaptor available; bad oversight of the company that makes them?
Or maybe they didn't see the need, as tubes with car type valves are more common. Which means seeing
what you can DIY.

Quoted message said:

"Traveller v.116" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I found a neat little gadget called tireflys. Sold in a 2-pack for around $7, they're little
watertight capsules that contain a blinking LED, powered off three pocket calculator button cells,

and

Quoted message said:

screw onto the valve stem. Works fine for car type valves, havn't tried

them

Quoted message said:

on prestas. A simple vibrating spring motion sensor activates them when

the

Quoted message said:

wheels spin. On the ones I have, the sensor wasn't sensetive enough, but tweaking it wasn't too
much trouble. They come in many colors, including a multicolor type. For practical

reasons,I chose amber.

Josh Gatts said:

Those look pretty neat. Do they come with a presta adapter, or do you have to fudge something?

Some brands do, some brands do not. At the very worst you'll have to dig in your toolbox and pull
out an extra adapter for the other wheel.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Eventually I'd like to get this system as cheap as possible -- < $2.00/spoke light. How much could
a coil, rectifier, capacitor and LED cost made en

masse?

Quoted message said:

Fifty cents?

I think it was Z-leader that did this. But they used more than one LED. IIRC, it sold for just
under $20.
--------------
Alex

jim beam <[email hidden]> in

Quoted message said:

Message-id: <[email hidden]> writes:

. . .

Quoted message said:

for $4.99, you can buy a good little blinky from nashbar

Too much money. It needs to be in a 99 cent store.

EVERYBODY must get lit.

Bret Cahill

"Traveller v.116" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

"Josh Gatts" <[email hidden]> wrote in
:"]news:[email hidden]:

Quoted message said:

"Traveller v.116" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I found a neat little gadget called tireflys. Sold in a 2-pack for around $7, they're little
watertight capsules that contain a blinking LED, powered off three pocket calculator button

cells,

Quoted message said:

Quoted message said:

and

Quoted message said:

screw onto the valve stem. Works fine for car type valves, havn't tried

them

Quoted message said:

on prestas. A simple vibrating spring motion sensor activates them when

the

Quoted message said:

wheels spin. On the ones I have, the sensor wasn't sensetive enough,

but

Quoted message said:

Quoted message said:

Quoted message said:

tweaking it wasn't too much trouble. They come in many colors, including a multicolor type. For
practical

reasons,

Quoted message said:

I chose amber.

Those look pretty neat. Do they come with a presta adapter, or do you

have

Quoted message said:

Quoted message said:

to fudge something?

--Josh

As far as I know, there's no presta adaptor available; bad oversight of

the

Quoted message said:

company that makes them? Or maybe they didn't see the need, as tubes with

car

Quoted message said:

type valves are more common. Which means seeing what you can DIY.

Looks like you could just use a regular presta-to-Schrader adapter, which are like $1 at the LBS.

--Josh

Alex Rodriguez <[email hidden]> in

Quoted message said:

Message-id: <[email hidden]> writes:

In article <[email hidden]>, [email hidden]

says...

Quoted message said:

Eventually I'd like to get this system as cheap as possible -- < $2.00/spoke light. How much could
a coil, rectifier, capacitor and LED cost made en

masse?

Quoted message said:

Fifty cents?

I think it was Z-leader that did this. But they used more than one LED. IIRC, it sold for just
under $20.

WAY too much money for a populist.

99 Cent store sells a red flashing light that runs on 2 AA batteries. To be sure the mounting
bracket is a piece of [censored] -- it'll break on the first bump -- and batteries aren't included but it
has a sophisticated circuit and 3 LEDs.

Bret Cahill

Traveller v.116 said:

Quoted message said:

Quoted message said:

I found a neat little gadget called tireflys.

Those look pretty neat. Do they come with a presta adapter, or do you have to fudge something?

As far as I know, there's no presta adaptor available; bad oversight of the company that makes
them? Or maybe they didn't see the need, as tubes with car type valves are more common.

I suspect they don't see a large enough market for bicycles, let alone bicycles using a valve that
they've never heard of. Tireflys were probably invented for the ricer crowd. I doubt the market for
presta Tireflys would even be able to support itself if somebody did make them -- but maybe.

Regardless, there's no reason you couldn't use a regular presta->schraeder adaptor (although all
that weight flopping around the end of your valve stem might be undesirable).

Quoted message said:

Which means seeing what you can DIY.

And if you're going to DIY, might as well DIY a way to hook the Tirefly to a spoke rather than
putting it where it's in the way every time you want to inflate...

--
Rick "Now a Flying Tire would be cool..." Onanian

(BretCahill) said:

Quoted message said:

for $4.99, you can buy a good little blinky from nashbar

Too much money. It needs to be in a 99 cent store.

There's a $1 store near me that sells a pack of three or four of them, I think with a strap, for (of
course) $1.

They're not too great, but they're OK. The pack comes with one star-shaped, one heart-shaped, one
arrow shaped, and maybe one other shape I can't remember. They only have one mode, steady blink, and
they come complete with batteries.

They're bright enough to be useful, but if I commonly rode after dark, I wouldn't want to
depend on them.

Quoted message said:

EVERYBODY must get lit.

Bob Dylan feels the same way.

Quoted message said:

Bret Cahill

--
Rick Onanian

BretCahill said:

I got the 120 v coil from a 6 v power supply (50 cents at used stuff store) and a welding magnet
(99 cents at Harbor Freight) and taped the coil and a bi color LED to the spokes and the magnet to
the seat stays. It was very dim but encouraging. I bought a more efficient red only LED, a bridge
rectifier (99 cents), used the 1 m F capacitor from the power supply and broke the magnet and
taped half to the chain stay half to the seat stay. This was a great improvement. The capacitor
actually keeps the LED on for the entire rotation at speeds above 5 mph.

Eventually I'd like to get this system as cheap as possible -- < $2.00/spoke light. How much could
a coil, rectifier, capacitor and LED cost made en masse? Fifty cents?

Bret Cahill

Did you use any kind of resistor to limit LED current? If not, then the LED is probably subjected to
very high pulses of current as the coil passes the magnet. Depending on your setup and how fast you
move, this could damage the LED or at least shorten it's usefull life a lot by dimming it's output.

Adding or increasing the resistance in series with the LED will help protect it, and improve
it's ability to stay lit, maybe even while stopped at an intersection. This also means the cap
has to charge to higher voltage, which could be accomplished with a stronger magnet, more
windings on the coil, using more efficient diodes, or by moving the coil closer to the rim (or
closer to the magnet).

Also I would think that a single rectifier would be more efficient than a bridge, because you
eliminate one diode drop and because your system is by nature DC, so if it's properly oriented two
of the diodes in the bridge are never on anyway and one just wastes power. Also you could use an
efficient schottky diode which is not normally available in bridges. This means you can't light the
LED by spinning the wheel backwards, but oh well.

Interested to hear what you think about this, I have been planning to build something very much
like this.

Adam

[email hidden] (BretCahill) wrote in :"]news:[email hidden]:

Quoted message said:

I got the 120 v coil from a 6 v power supply (50 cents at used stuff store) and a welding magnet
(99 cents at Harbor Freight) and taped the coil and a bi color LED to the spokes and the magnet to
the seat stays. It was very dim but encouraging. I bought a more efficient red only LED, a bridge
rectifier (99 cents), used the 1 m F capacitor from the power supply and broke the magnet and
taped half to the chain stay half to the seat stay. This was a great improvement. The capacitor
actually keeps the LED on for the entire rotation at speeds above 5 mph.

Eventually I'd like to get this system as cheap as possible -- < $2.00/spoke light. How much could
a coil, rectifier, capacitor and LED cost made en masse? Fifty cents?

Bret Cahill

A web search found me all kinds of LED wheel lights. There's a flashing LED reflector - Fairly cheap
and lightweight. A rig that includes four LEDs mounted on the spokes, w/ a small battery box on the
hub via a crappy plastic strap. Lightweight, but not very durable. Sold as one set per wheel, at way
too much cost to justify the cheap construction. A self contained, dynamo powered disc with
multicolor LEDs. Expensive and heavy, but looks reliable. May have mounting issues with disc brake
systems. Hokeyspokes - a spoke mounted system with several multicolor LEDs. Many lighting effects.
Expensive. And about a half dozen variations to the tireflies theme.

(BretCahill) said:

Alex Rodriguez said:

I think it was Z-leader that did this. But they used more than one LED. IIRC, it sold for just
under $20.

WAY too much money for a populist.

99 Cent store sells a red flashing light that runs on 2 AA batteries. To be sure the mounting
bracket is a piece of [censored] -- it'll break on the first bump -- and batteries aren't included but
it has a sophisticated circuit and 3 LEDs.

Check these out: glow-necklaces-light-sticks-raves.comproduct.aspOpen ↗
fireflashers.combody lights.htmlOpen ↗

The button style lights have a wide field of view and are surprisingly visible at a distance. These
may not be applicable to bikes for other reasons such as quirky switching and mounting, but they
offer clues as to how cost effective this stuff can be. Each one has a 2 piece threaded metal
housing, encapsulated printed circuit board with 2 or 3 LEDs built in, 2 or 3 button cell batteries,
and 2 strong disc magnets. That's a lot for an asking price of less than $1.

Chalo Colina

[email hidden] (Chalo) wrote in :"]news:[email hidden]:

Quoted message said:

The button style lights have a wide field of view and are surprisingly visible at a distance.
These may not be applicable to bikes for other reasons such as quirky switching and mounting, but
they offer clues as to how cost effective this stuff can be. Each one has a 2 piece threaded metal
housing, encapsulated printed circuit board with 2 or 3 LEDs built in, 2 or 3 button cell
batteries, and 2 strong disc magnets. That's a lot for an asking price of less than $1.

Chalo Colina

They can be used for biking. At the price, you can stick them all over your favorite riding jacket.
You might look like a space alien or something, but you'de get noticed.

I've just bought an old mountain bike for fooling around on. Its a Giant Cadex ALM1. In nice enough
condition - bonded aluminium frame and with the original Suntour microdrive gearing - so it must not
have done too much work. It has a very basic suspension fork - labelled Giant Zorbers.

In the back of my mind I remembered hearing of them before and did a google groups search (thank you
Mr Google) and found there had been a product recall owing to "Suspension fork could come apart and
cause loss of control" which sounds a little unpleasant.

Can anyone remember these forks and what should I look for to check that they are safe/have been
rectified.

Thanks in advance Hugh Fenton

"Hugh Fenton" <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

I've just bought an old mountain bike for fooling around on. Its a Giant Cadex ALM1. In nice
enough condition - bonded aluminium frame and with the original Suntour microdrive gearing - so it
must not have done too much work. It has a very basic suspension fork - labelled Giant Zorbers.

In the back of my mind I remembered hearing of them before and did a google groups search (thank
you Mr Google) and found there had been a product recall owing to "Suspension fork could come
apart and cause loss of control" which sounds a little unpleasant.

Can anyone remember these forks and what should I look for to check that they are safe/have been
rectified.

Thanks in advance Hugh Fenton

If I recall right, there was a Chinese or Korean made lowbudget suspension fork that had that issue;
something about bad welds near the stem that was subject to premature failure. They appeared under
several brands. Your local bike shop guy should be able to tell you if you have the bad forks.