A simple and cheap LuxIII bikehelmet lamp idea?

OK, so I've been using a PT Aurora headlamp while bicycling to work in the morning (60min one way). It's ok, but I need occasionally more throw when there's no streelights around. I like headlamps because it lights exactly the area I'm looking at unlike mounted bike lights and it's easy to make myself visible to cars by just looking to that direction.

I had been thinking of getting PT EOS, but they seem to be ridiculously priced in Europe or out of stock where cheaper. So I thought maybe I could make something; maybe not stylish, but cheap, easily found parts and not a lot machining needed. I have no experience with modding lights other than one direct driven 3D Mag with Hotlips, so I'd ge grateful for some feedback.

So to the point, the (very rough) idea I have, would this be workable or > dev/null?

The casing would be a cone shaped 1/2dl or 1dl steel measuring cup used in kitchen. The handle would be bent and somekind of attachment thingie rigged to clasp it to the helmet.

Light source would be LuxIII emitter or star. I can get locally LXHL-PW09 or LXHL-LW3C for a fairly reasonable price, specs given are Imax 1000mA and Vf typ. 3.70V. It's a K bin I guess?

As a reflector I'd use a camless D-Mag reflector or some other from some cheap C/D-cell light. Though the Mag reflector makes such tight hotspot I'm not sure it's usable.

I don't know if somekind of heatsink would be necessary? The outside operating temperature will be 0C +-15C, so fairly cool, and and the windchill would make it even cooler. The led would be attached to the bottom of the cup or if it needs to sit higher, on top on some washers or something which might also act as a heatsink.

To protect the led from the elements, a standard Mag lens epoxied/sillyconed inside the cup. Maybe Scotch-tape to diffuse the thight spot from Mag-reflector.

The powersource would be NiMH AA's or AAA's which I have at hand, C's or D's could be an option later on. Either attached to the helmet or on a belt pack. If I interpret the DD reference sheet correctly, 3xAA would be ideal, 3xAAA doesn't give enough current. All 4 cell configurations need to be resistored, would that make 4xAAA unusable because AAA capacity is so low compared to the bigger cells?

If the Mag reflector gives too tight focus, maybe a 25degree collimating lens from Polymer Optics instead. 6degrees would be way too tight I think.

I know there are some (several?) difficulties, like aligning the emitter (star would be a little easier) and the reflector, but this could be a fun project, if it is doable. What say my more experienced colleagues?

ps. Sorry for long and winding post.

Im not sure if they exist anymore but we used to buy effervescent Vitamin C tablets in small aluminium tubes, each tablet used to be wrapped in foil and the tube had an orange plastic top. These tubes would be ideal for your application. Some cigars are found in aluminium tubes too.

You would stick your emitter or star to a copper disc ( money coins are good ) of the right size. solder a long wire to the emitter/star. drill a hole for the wire to pass through at the bottom of the tube, and then stick all of it to the bottom of the tube. Optics would be best for this as you could then cut the tube to the right height and just silicone the optics to the tube.

You could use another tube of this kind as battery housing maybe using a 3AA-to-D adapter.

there you go a 10 minute job. (maybe not)

Amonra said:

Im not sure if they exist anymore but we used to buy effervescent Vitamin C tablets in small aluminium tubes, each tablet used to be wrapped in foil and the tube had an orange plastic top. These tubes would be ideal for your application. Some cigars are found in aluminium tubes too.

Click to expand...

Thanks, that's a pretty good idea. I just happen to have such a tube laying around somewhere, I thin'k I'll try that. I'll pick up the parts today and start working on it.

good just tell me how it goes

Sorry to drag up an old thread but I totally forgot to follow up on this last fall. Here's the end result.



As you can see, the scrap box was heavily used. Only items bought were the luxeon star, a 6 degree collimating lens and the batteryholder. The body of the lamp is cut from an old aluminium felt pen. The star, a coin as a "heatsink", the body and a light Alu L-profile for the leg is joined together with pop rivets. A spacer is epoxied on top of the lens to make the assembly more rigid and weatherproof. I used duct tape to fasten the lamp to the helmet, now I'm testing velcro glued to the helmet and the lamp leg.

I've been very happy with the result, it's good enough fo my use. Ofcourse it could have more throw, more output overall and a better beam pattern.. the usual stuff