LED Headlamp

[Ian]

The "safe" circuit adds a transistor and 2 resistors to each chain which is far more complicated than simply feeding each chain through a resistor from a common voltage regulator, itself a tried and tested method.

I don't quite see the logic behind the safe circuit as it would use less components to provide a regulator for each chain.

 

[Jeremy]

But you wrote:

care must be taken to ensure that the current remains within limits throughout the full battery voltage range

I suspect you think I was trying to be a smart arse, from the tone of your response, when in fact I was really just addressing the point you yourself had made in the first place....................

Jeremy

 

[flecc]

How often I've seen this, two engineers arguing with equally valid but different positions.

No matter how long it's argued, you'll both end up where you started, because you're both right.
.

 

[Ian]

I suspect you think I was trying to be a smart arse, from the tone of your response, when in fact I was really just addressing the point you yourself had made in the first place....................

Jeremy

No offence was intended Jeremy. As is so often the case with purely written communication with its absence of body language there has been a something of a misinterpretation of my "tone".

Of course Flecc is right, there is more than one way to crack an egg, neither of them being necessarily best.

 

[Haku]

Hmm, that's really quite something Ian, makes my effort look a little err amateur. I used my multimeter to get a rough idea of the current draw, powering 21 LEDs draws about 0.05A from my battery - definitely have to re-do my front reflector with double the lights cause I want much more light and to angle some of them down so I can have a high/low beam setup where the low beam points to the ground and can see it well without bothering other cyclists/pedestrians along unlit cycle tracks, using the high beam when nobody's about.

 

[Ian]

Hmm, that's really quite something Ian, makes my effort look a little err amateur.

Not at all Haku, a different approach that's all, I went for sheer weight of numbers to beat the darkness into submission! It's reflected in the current consumption of 180mA though, but still negligible really.

You point about positioning LEDs at different angles is a good one, I slightly dished the mounting plate to achieve a wider spread, I also used LEDs with 2 different beam angles, supposedly 12 and 25 degrees although the 12 degree ones have the widest spread! Anyone who likes a lottery should try buying direct from Chinese suppliers.

 

[giguana]

would love a picture of the beam shape on a wall.

 

[Ian]

would love a picture of the beam shape on a wall.

No sooner said than done...

 

[Haku]

Was idly doing an eBay search for some UV LEDs to make some sort of add-on for my Asus Eee laptop to light up the keyboard (the keyboard looks whitish under UV and the surrounding 'pearl' coloured plastic doesn't react to UV light) and amongst the multitude of UV LED torches there was a bike light.

A UV bike light?

Would that be of any use?

Surely it would have to be quite powerful and only UV reactive things will glow under it, perhaps someone with some spare time & curiosity could test a pure UV bike light and a hybrid white/UV LED bike light setup ?

 

[keithhazel]

front lights and back lights tell me the best please

i have a Quando which although has a front light i want "real" lighting for badly lit streets, i dont ride much in the dark but when and if i do i want as good as i can get without breaking the bank... ..oh i forgot i already have getting the bike..... ...i want either 1 or 2 front lights that are bright enough to not only let cars know im there but good enough to let me see the road well enough, on the back again i have a light but i want more as the rear is most important, i have just bought a set of "basil" panniers, my thought was to get 2 more good rear lights and fix them to the pannier with possibly the battery on the inside if needed...i have looked on the net but there are so many to choose and as i have no experience i dont want to buy a bargain and find its not bright enough to be safe, but on the other hand im not paying stupid sums of money either....i also think a bike could do with some sort of side lighting so that cars or people can tell from a side you are there..unless im just getting paranoid.. ...can anyone come up with a shortlist that will cost me say no more then £60 to be lit so i can see where im going and they can see me...have found the odd link but not up to date on this forum so with new things on the market every day might as well have up to date info.
my gratitude is overflowing as i cannot trawl the endless pages no more without my head going meltdown