A Non-friction bicycle lights generator (dynamo)

Look in the mirror!

In message , ":::Jerry::::" wrote

A bicycle travelling at 5 mph and a car following at 55mph gives a closing speed of 50mph.

That all depends on how steep the hill is!

traditional dynamo. With this innovative, electrical generating system you will not feel any extra weight when you are cycling. "

No drag = no power transfer = no electrical power generated; QED

Perpetual motion? I recall hub dynamos which didn't rely on friction drive.

Unfortunately they didn't put out enough power, especially at low speed. You could see the lamps flicker as they turned :-) Bottom-bracket mounted dynamos are pretty good as they don't scrub like the sidewall-driven ones can, but they can be prone to slipping and/or rapid wear because the back tyre dumps loads of crap on them. You can get toothed-belt drive dynamos that are driven by a pulley attached to the side of the hub. A properly set up high-quality sidewall-driven dynamo can still work pretty well anyway.

Posted on another group:

cheers, Pete.

Just a tad expensive though!

so about 600 yards

applied

Yes but the car has at least 150 Watts worth of headlights....

The point of the flashing is that human peripheral vision is *far* more sensitive to movement (and hence flashing) than it is to static images. The result is that a flashing light makes a cyclist many times more visible when approaching junctions to the side of a driver etc. This is also the time they are usually most vulnerable since they are presenting the least visible "target" area.

So in other words, if you find the flashing irritating then good! That is the whole point.

standard

images.

This is

presenting

So I'll ask again, why are flashing lights not use for tail and head lights on motor vehicles if they make for safer roads?...

In message , ":::Jerry::::" wrote

To avoid confusion with the existing safety lights on a car that do flash. A flashing light on a car warns of a potential hazard. A following vehicle will slow down or take evasive action when the car in front has a flashing light (hazard warning or turn indicators)

Headlights on a car serve two purposes:

1. To illuminate the road ahead to aid safe passage
2. To indicate the presence of a vehicle to other road users.

Now a flashing headlight would do a great job addressing point 2, but I for one wouldn't like to drive a car with flashing headlights.

Taillights basically have a single purpose, that of indicating the vehicles presence to other road users following. In theory a flashing tail light would be fine. But the back of the car also contains turn indicators whichwhen activated display a flashing light, albeit yellow/amber in colour. So flashing taillights could cause confusion. And then there's the added factor of the brake lights to include.

Imagine a car indicating to turn left, at night, whilst braking. From behind you'd see two flashing red taillights, both possibly drowned out by the brake lights, along with a flashing yellow/amber turn indicator. I don't know about you, but I'd find that pretty distracting, especially if the driver of the vehicle in front kept applying the brakes intermitantly.

And then you've got to take in to account the cost of light sources that could stand being switched on and off rapidly whilst still giving acceptable levels of illumination and longevity.

Flashing lights increase cyclists' safety and visibiliy when compared to traditional sources of illumination on bikes, although not as much as the installation of lighting comparable to that found on cars and motorbikes. However, the latter is impractical on a pushbike and so flashing lights provide a compromise solution that improves upon the more traditional solutions.

Cheers Clive

In message , Clive Summerfield writes

I think flashing lights probably help when used in conjunction with constant lighting, well for the rear anyway. I don't particularly like just a flashing light.

While of course 'common sense', and I made an effort to have good effective lights on my bikes There's no evidence really though that lights of any sort on cycles do have any benefit from safety/being seen POV. hoe many times have we heard - or said - 'I see loads of cyclists with no lights.....'

and their ilk are pretty impressive, and in fact intended for night time off-roading really and are totally overkill for the road

That is not an issue...

No one has mentioned the real reason for flashing bike lights.

The battery can last longer with a given degree of (peak) illumination.

Pure and simple, you can be more noticeable per watt hour with a low duty cycle bright light than a dim continuous one.

However outside of the suburbs, where lighting is non existent, cycling without a proper headlamp of a continuous flavour on a moonless night is a recipe for distaster.

OTOH as a kid I often cycled with no lights at all in moonlight...as long as no traffic was around.

Yes, but they're often seen rather later than one might wish.

Actually, most of the "flashing" bike lights are actually "occulting" (i.e. on more than they are off) if one is to be strictly accurate.

Even the LEDs which seem to be on continuously are generally being switched, but too fast to be noticeable, except by the strobing effect if on the move.

Chris

Sorry to wade in here, but to be honest, Jerry, your contributions to this thread appear to be nothing but slagging off other contributors, mis-information and plain old lies.

What's your beef with cyclists? Or are you just a grumpy old man?

Whatever the case, is there any chance you might be doing something other than just trotting out the same 3 replies over and over again?

But it's OK for cyclists to have flashing rear lights. Is that a motorcycle up front with a faulty rear / brake lights or just a cyclist...

giving

That is not a problem, such lighting is used elsewhere.

compared

I agree that high intensity lights are better than what has gone before, I just don't see the need for or any safety gained, from having them flash.