I finally got my trusty digital power supply back. It must be more than 10 years old by now, but it still works like on the first day ;-) Don’t remember how much I payed for it, but looking at what’s available today it must have been quite a lot.
Here’s a picture of the 3W LED bar I bought at Seeedstudio a while ago. I ‘stole’ the image form their shop. I hope they won’t sue me (would be counterproductive, wouldn’t it ?).
The bar is rated 240mA at 12V. Here are some videos to illustrate the MASSIVE brightness of it. I’m using my power supply in current limiting/auto shutdown mode, so I don’t need a resistor. Don’t use a standard wall wart / power supply without current limiting mode !
Increasing the voltage by 0.1V starting at about 8.7V:
This is filmed through 10 sheets of laser printer paper:
These babies will go on my bike when I have some time to do it. I’ll need to cook up a DC/DC converter to get 12.x volts with current limiting capability. LM3410 seems a good choice. That way I could run it using 4 AAA cells. Riding my bike in the dark will look like a “ray of light” ;-) Maybe I’ll find a person with a camera that can do long time exposure. Too bad my current digital camera can’t do that. The Nikon Coolpix 990/5 I had before could do that no problem. In theory I “could” use my old SLR, but do they still sell film cartridges for these ? Nah, too much trouble with that.
→ Update 1: 18.08.2009:
Switching to LT1618. Includes voltage and current regulation/adjustment. There’s also a LTSpice model for it.