Bright rear red light (DX components)

[atropine1]

Hi,

I have the Ultrafire WF-501B Philips Luxeon K2 Red LED Flashlight which is nice and bright and thought it could make a nice rear flashing light. It's single mode only and probably too directional for maximum visibility
http://www.dealextreme.com/details.dx/sku.20333

Would anyone know of a prism or cone or something I can put over the lens so that the light is visible to all of the rear and the sides?

When I think about it, I probably should have just got a white led light as red cones are probably available somewhere. Due to the red led however I need a white cone or some cone prism type thing to go over the lens
Also want to make it blink, but dealextreme seem to have sold out on all the boards that take 8.4V and strobe. (only have RCR123A's at the moment) & I think that's the only cheap place for that sort of stuff.

 

[Benson]

Hi,

I have the Ultrafire WF-501B Philips Luxeon K2 Red LED Flashlight which is nice and bright and thought it could make a nice rear flashing light. It's single mode only and probably too directional for maximum visibility
http://www.dealextreme.com/details.dx/sku.20333

Would anyone know of a prism or cone or something I can put over the lens so that the light is visible to all of the rear and the sides?

I'm not sure what exactly you're looking for -- there are pure diffusers that will give good visibility of the light, but not as much projection, or lenses that will actually project a good beam, giving more light output, but at the cost of some extreme-angle visibility.

My pick, one of the latter, would be sku 1918 or 1919; unfortunately, neither of them quite fit that light, but either could be adapted. I have the small one, and it'll project over a 45 degree wide beam, but rather narrow vertically (so light isn't wasted as with an overall wide angle); the vertical width is rather sensitive to distance, so you can get it as wide or narrow as you like. The horizontal width is fairly constant, though.

Not sure about diffuser cones -- there's plenty, but I never went shopping for them.

When I think about it, I probably should have just got a white led light as red cones are probably available somewhere. Due to the red led however I need a white cone or some cone prism type thing to go over the lens

Well, the red emitter will be rather more efficient than a white emitter and filtration; I'd definitely do this the way you are.

Also want to make it blink, but dealextreme seem to have sold out on all the boards that take 8.4V and strobe. (only have RCR123A's at the moment) & I think that's the only cheap place for that sort of stuff.

A thought: Cars don't (usually) have blinking tail lights, and are quite visible. Most flashy rear lights need to flash mainly because their 5mm LEDs aren't bright enough to be noticed without it; this design shouldn't have that problem. Blinking's still an option, but IMHO not really needed or desirable to get good performance out of this setup.

Anyway, there's also KD (kaidomain), another site with some historical relationship to DX (I think the partners in a similar now-defunct site, went separate ways and founded KD and DX after it failed?). Similar concept (free shipping and low prices, but not the awesomest service or product quality), some of the same products, and some unique on each side. You could check them for different boards, but if it's the same board, from the same supplier, they probably won't get it in stock any sooner. (Or find a 4.2V board, and use 1 RCR123 and a spacer?)

 

[atropine1]

I'm not sure what exactly you're looking for -- there are pure diffusers that will give good visibility of the light, but not as much projection, or lenses that will actually project a good beam, giving more light output, but at the cost of some extreme-angle visibility.

Well my old rear bike light had multiple 5mm led's facing through 120 degrees horizontally. I really liked the high visibility from any rear facing angle. The red torch ofcourse doesn't have such qualities. It has a tight hotspot and area around the hotspot (I've forgotten the term for that right now). As I see it, that's not really what you want for a rear light. better for it to be equally bright through a 120degree (maybe 90degree is ok) horizontal angle with low vertical angle projection through that range, for as you say light radiating at a broader angle is wasted when you're not trying to light up the road or the sky, but more a beacon so car drivers don't' run you over.

Could you advise which of those lenses would be best for this use?

My main reason for wanting a blinky is because I think Rear flashing red lights on bikes are so widespread that a car driver instantly knows that a bicycle is infront of him, even though he may not be able to see the bicycle or the rider, so can adequately mentally position the rider on the side of the road and prepare to move out onto the road a little to overtake.
I figured a normal red light may not instantly trigger the same recognition and so not be as safe for the bike rider. This mightn't be the case in Europe where I think cycle lights are often regulated by governments & also dynamos are a lot more popular. But in my country it's all flashy led lights that I notice.

Thanks for the other info too.

 

[pe2er]

This is how I built my rear light:


It (the top light) is a 1 watt red Luxeon emitter, with a ~20 degrees lens. It is built into a clear red retro reflector. The lens protrudes through a hole in the reflector.

The buildup is similar to the commercial 'Superflash' light, mounted below my own light in this picture. It makes the light visible from a wide angle, and makes it light up the roadsigns far behind me :D

Over here (Europe, the Netherlands), flashing bike lights are not allowed. All lights must be steady on. Reason for that, I'm told, is that a steady light is easier to position for other (car-)drivers. And I must admit, it is very hard to establish the path of a red flashing rear bike light through heavy rain. Other European countries (like the UK), do allow flashing bike lights. Go figure...

 

[Benson]

Well my old rear bike light had multiple 5mm led's facing through 120 degrees horizontally. I really liked the high visibility from any rear facing angle. The red torch ofcourse doesn't have such qualities. It has a tight hotspot and area around the hotspot (I've forgotten the term for that right now). As I see it, that's not really what you want for a rear light. better for it to be equally bright through a 120degree (maybe 90degree is ok) horizontal angle with low vertical angle projection through that range, for as you say light radiating at a broader angle is wasted when you're not trying to light up the road or the sky, but more a beacon so car drivers don't' run you over.

Could you advise which of those lenses would be best for this use?

Well, neither of them fits exactly; the ripple-lens I have (the smaller one) has between 45 and 60 degree spread -- I'd consider 90 about perfect, so this is really narrower than I like. A plain conical or cylindrical diffuser will give you well over 180, and the same vertically, so it spreads your light over way more area. I don't know that any off-the-shelf diffusers exist to give substantially more light in a single arc like you want for this, and I'm pretty sure none of the DX lenses are quite as wide as you want.

Like I said, my choice, since both fall short, would be one of those two lenses (and I'm not sure which -- I'd probably order both, and try them to figure out which I liked), but the diffuser would be a perfectly reasonable option too.

 

[kombiman]

another consideration is that you want it diffuse as you can get, bright flashy of spots pointing back at drivers can be too bright and really **** ppl off, ever followed a late 90's Hyundai excell with the bad weather light on on a nice clear night? It is like looking into a re headlight.

I prefer a number of stationary and a flasher but not too bright. Also put them on your helmet and pack.

Dunno where you are but here in Oz it is the fine line between being seen or being raged by a car full of knobs

 

[hit4six]

I go for one bright and steady, one low power and 'strobe' ie scrolling from top to bottom. Nice to have a back-up.

I've got the same torch. If you can get a different reflector which sits lower around the emitter you get a diffuse beam with no central 'hot spot'. I use the reflector from another dx p60 dropin. I tried the white diffuser tip from dx and i thought it was not any use in this application.

 

[hit4six]

Very nice peter, good side visibility. I was wondering how you mounted it, i clicked the picture and saw. I've got an idea for a mount for the torch, neater than my last, still think diy would be better.

If ever I can post pics I'll show how I get all round visibility from a red 501b torch with standard aluminium reflector. It sounds very unlikely but one and a half lens covers/filters for trail tech mr11 hid lights works better than anything else I've tried.

 

[hit4six]

Thats the kaidomain red p4 dropin with standard orange peel reflector. Red looks white because of the intensity. ed with the trail tech lens cover as mentionned above.

 

[Offroad'Bent]

Would you mind giving some more details about this?
Can you suggest a small host flashlight for this drop-in with a flashing mode?
Thanks!

Thats the kaidomain red p4 dropin with standard orange peel reflector. Red looks white because of the intensity. ed with the trail tech lens cover as mentionned above.

 

[hit4six]

to answer, a) I'd be surprised if you really wanted this flashing! You'll find discussion of high power blinkes like Planet Bike. If you did want it flashing, I think you would have to make your own drop-in buying the led, driver and reflector seperately. You'll find a project on mtbr forums. and b) I have only used the Ultrafire WF-501B body, these dropins all fit. (As it turns out, the Dx light is also one of the cheapest hosts, I paid around $18 for my others with latest white cree emitters.) I think I'm repeating myself but just in case, you can't mount it on the side of the seatpost by the way, it obstructs you.

And more details - I thought I had edited my post on this thread but obviously I didn't. I meant to report, I used the red p4 with two layers of the trail tech lens cover material and that was just about ok, with one it was definitely too bright. So perhaps the red 18650 philips equipped torch from DX would be a better choice, sku 20333. Surely still too bright without any diffuser despite what I suggested in an earlier post. Among my spare bits I had one white trail tech hid diffuser one amber, so that is what I used. They come in packs of two. If you want to buy them I expect amber would be most suitable. It doesn't have as much effect on the colour as you might think, but it diffuses, dims, and cuts glare well.

 

[Offroad'Bent]

Oh, I want this flashing. I also want something more powerful than my 1/2W Planet Bike. I'm thinking closer to the Dinotte 140 lumen flasher for daylight visibility.

I'll check out the MTBR forums.

Not worried about a seat post- it's going on my rack on my recumbent.
I'm still hoping for a flashing light running on 1 or 2 AAs, rather than 18650 batteries.

to answer, a) I'd be surprised if you really wanted this flashing! You'll find discussion of high power blinkes like Planet Bike. If you did want it flashing, I think you would have to make your own drop-in buying the led, driver and reflector seperately. You'll find a project on mtbr forums. and b) I have only used the Ultrafire WF-501B body, these dropins all fit. (As it turns out, the Dx light is also one of the cheapest hosts, I paid around $18 for my others with latest white cree emitters.) I think I'm repeating myself but just in case, you can't mount it on the side of the seatpost by the way, it obstructs you.

And more details - I thought I had edited my post on this thread but obviously I didn't. I meant to report, I used the red p4 with two layers of the trail tech lens cover material and that was just about ok, with one it was definitely too bright. So perhaps the red 18650 philips equipped torch from DX would be a better choice, sku 20333. Surely still too bright without any diffuser despite what I suggested in an earlier post. Among my spare bits I had one white trail tech hid diffuser one amber, so that is what I used. They come in packs of two. If you want to buy them I expect amber would be most suitable. It doesn't have as much effect on the colour as you might think, but it diffuses, dims, and cuts glare well.

 

[hit4six]

looks like you'll build your own. I should have said, I think that the mtbr post showed someone choosing the led and driver for a flashing light brighter than the Philips, but it could have ended up as a steady, I can't be sure.