Rear flashers for My Bike Light Project

[mkrabach]

Forget all the commercial rear flashers, Do Your Own! Finally got more parts from dealextrene.com and did three more prototypes in My Bike Light Project. See Prototype 10, 11, and 12 in the link below. L2 Optics with 8x25 deg sub-lens gives a fantastic wide angle flasher. But favorite turned out to be modifying an old Vistalite VL500. Looks just like the original, but does not act like the original. Included beam shots comparing them with the old Vistalite VL500 and VL700, and videos of the flashing modes. Used 3 watt Cree LEDs so they are good enough for daylight, at night you want to be the last in a group of bikers.
http://www.kayakaccessri.info/krabachwebsite/bike_light/bike_light_project/intro.html

 

[mckevin]

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and reported...

 

[TheWalkman]

Mkrabach,

Very impressive.

I had an old Vistalite die the other day and this looks like just the project to bring it back from the dead.

If this thing is as bright as it looks, I wouldn't want to ride behind you!

A couple of questions:

What kind of runtime are you getting off of your AA?

From your pictures and videos, it appears the optics aren't adding alot of difference between Proto 10 and 12. Any thoughts?

(I have a feeling my friends with Dinottes will lust with envy.)

Thanks!

 

[mkrabach]

Yes, it it bright from the back but, I tend to ride the back of the pack. So cars see me first. For prototype 10 and 12, I get about 6 hrs runtime. When the battery drops to about 1.15 v the flashing stops and the light stays on steady. I think it is from the fact that I set the regulator to the lowest output voltage (1.4v) when the flasher is in low mode. I do go into detail in the web page. But hold onto the old vistalite, I have a new variation that I will put up which is a different regulator (no pot but the same operation) with two red LEDs. The leds are a cheaper DX SKU 11017 and are I think 1 watt versions. I use the 2 LEDs in series to drop the voltage so the regulator which outputs 3.7v or thereabouts, does not have to be adjusted via pot like Prototype 10, 12. It also draws the battery down below the 1.15 v to something under 1v, better utilizing the battery, and giving a runtime of over 24 hrs. I ordered new parts from DX and will do a flasher with two Cree red 3 watt LEDs in series with the same regulator that I will do up in prototype 13 (coming soon). With two LEDs the beam pattern from the Vistalite optics is different that the single LED, sort of a wide diamond pattern. Since the regulator DX SKU 7302 is a 500 ma (325ma measured on high) on that flasher, the Cree version should not pull any more and the result should be brighter but with about the same runtime. Stay tuned. There is the usual wait for parts from Hong Kong.

The differences between the proto 10 and 12, is such that proto 12 is a better bet because I can fit it in a Vistalite case. I have not yet found a case I can hack for Proto 10 with the L2 optics with the wide diffuser sub lens. The L2 optics also has the added fuss of filing channels for the power wires, as described first in Proto 2.

I am running out of old Vistalite flashers to convert. I have many bikes all with flashers mounted on them. So looking around for cases or cheap modern flashers that can be converted. Ordered one from DX and will see how that works, but is AAA so might be a little tight.

 

[Steve K]

Nice to see some tinkering and experimentation!

I have a question regarding the taillights, though. why use a white LED when you want amber or red light? You can get LEDs that produce just these colors, resulting in much better efficiency than generating a fairly complete spectrum of colors (i.e. white), and then thowing away most of that energy by using a color filter.

Steve K.

 

[mkrabach]

The white LED on proto 11 was to check out a non adjustable regulator and fitting components into a Vistalite case. It was the result of Proto 10 being great, but not finding a case for it. I had assumed that I could use a red cover plate with the white. Note that the regulator used has an output for a 3.7 vf LED, so using that on a red (2 vf) would kill it by overdriving it. As it turned, out a white has so much blue end of the sprectrum that the red coverplate dimmed it considerably. So I switched to a amber cover which passes much of the sprectrum. The photos dont do the brightness justice. In real life you dont dare look at it close up, the amber lets thru alot of light. This flasher is so bright that you could be used as a emergency highway flasher to carry in your car. Remember all these lights are prototype experiments for various combinations. Prototypes 10 and 12 are red and my new ones will be red LEDs.

 

[TheWalkman]

Mkrabach,

Did you consider using DX sku 3393 or 13613 for your prototypes?

http://www.dealextreme.com/details.dx/sku.3393

http://www.dealextreme.com/details.dx/sku.13613

I'm assuming the 13613 could be mounted directly to the heatsink in the Vista with some Arctic epoxy and it would be electrically isolated. This would certainly eliminate all the grinding you describe on your website.

Granted, since they're white, these LEDs might not be quite as bright through a red lens but mounting would certainly be easy.

Too, do you have any more details on wiring the 7882 regulator? DX doesn't seem to offer any details and I can't seem to find anything specific on CPF.

(I'm a relative novice to mods and would hate to fry the board. I've been hoping to see some bike light projects from from someone with more electronics knowledge than I. Great job.)

Your projects are really interesting. I'm thinking it might be time to retire my SuperFlash with these.

Cheers!

 

[mkrabach]

From my experience with proto 11 and the white LED thru red cover, I will stick to the red LEDs. The grinding is probably difficult if you dont have a bench grinder. It is pretty easy to grind the aluminum base, but is a very slow process since alot of heat is built up. And the star LED is being held in my fingers. Ouch! Takes about 3-5 minutes. I guess you could do it with a file, but it would be a fuss.

Info on the 7882 is split between my proto 10 and 12 pages. The wiring is seen in proto 10. The only difference I can see between the KAI and DX versions is the color of the board and you have to jumper the DX version. The KAI is already jumped.

You won't fry boards if you observe the voltage input limit stated in the DX or KAI pages. Some have found minor differences as noted on the respective comments pages on DX and KAI. All white, blue LEDs have the same forward voltage vf of 3.5-3.7 The red are from 1.8-2.2 depending on the brand. So you will not fry the board but could fry the red LEDs. That is why I used the potted version on the single red LED to reduce the output voltage. But on my new one Proto 13 (soon) I used two red in series to share the voltage drop. That is exactly what I do in Prototype 2 for 3 LEDs, if you dont realize it already. I have no knowledge how much electronics you are familiar with. Maybe all this helps. Note that in the flashing modes I have never got the heat sink (1/8"x width of Vistalite case) even warm. So if you have a thinner Al sheet for a heat sink to mount the LEDs on, you will be ok.

 

[mkrabach]

Another rear flasher prototype (Prototype 13) finished with more beam shots. Added Prototype 14 a variation on triple Cree 3 watt front light. Added note: these experiments document all the parts that I have purchased of the internet, mostly dealextreme.com, ledsupply.com, and taskled.com. So if you are curious on how different LEDs and regulators and optics perform, check out the site.
http://www.kayakaccessri.info/krabachwebsite/bike_light/bike_light_project/intro.html