Lights

I ordered one of these, because for £2.87 with free UK delivery how could I resist ?

G3 CREE Q5 400 LUMEN FLASHLIGHT/TORCH: Amazon.co.uk: Sports & Outdoors

It took weeks to come. It is very bright at first, but quickly runs the single AA battery down.

So I've ordered 6 more, and I'll connect up all 7 in series and use a transistor to drive them at constant current from a bank of 6 AA NiMH batteries.

They've arrived. They're not all exactly the same: the first one has a slide out lens for beam focus, but only one of the other 6 has this. The remaining 5 can only be focus adjusted by partially unscrewing the lens mount.

Test rig for beam evaluation:

I got a beam shape I like with 2 of them focused tight and aimed far, 2 more focused and aimed medium, 2 focused wide and aimed close, and the final 1 focused wide and aimed very close.

The compound beam at 400mA:

Hope vision one beams (on the same camera settings) for comparison:

At 400mA the DIY light has similar power draw to the vision one on high. It illuminated the path significantly less well, as you'd expect with lower quality emitters and optics. Nevertheless, it seemed like plenty of light to see by, so I think this will work.

Next step, mounting the emitters. I'll cut away most of the torch bodies, and embed the business ends in something that I can attach to the handlebars.