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DIYed headlamp on Kickstarter - Bosavi
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Devin Montgomery
(dsmontgomery) - MLife

Locale: one snowball away from big trouble
DIYed headlamp on Kickstarter - Bosavi on 05/26/2012 19:57:30 MDT Print View

Something I'm backing and wanted to share. Bosavi headlamp: up to 110 lumens (life: 23 hrs at 60, 70 hrs at 4), 2.1 oz w/ lithium battery, rechargeable by usb, not sure if it's regulated. Open source, DIY by the designer, Dan Freschl. $65 for the base model, funding ends June 15.

Cody Lebow

Locale: Orange County
headlamp on 05/27/2012 09:51:11 MDT Print View

Very cool, I'm going to back it.

Daniel Freschl
(djfreschl) - F
Re: DIYed headlamp on Kickstarter - Bosavi on 05/27/2012 16:19:38 MDT Print View

This is Dan Freschl, the creator of Bosavi.

First of all I have to say that you are all awesome!!! I have been working on the ultimate headlamp for almost two years and your feedback is showing that it has all been worth it.

Secondly, I tried not to load the Kickstarter page up with technical details. I figure the Backpacking Light crowd would appreciate it. I really geeked-out on this project. Here are some of the highlights:

1. PWM: The Cree LED is regulated with PWM (pulse width modulation). So basically the LED is turning on and off 400 times/second, which is much too fast for you to see. PWM is a more efficient way of driving an LED than using a resistor.

2. Feedback: The microchip is constantly reading battery voltage and modulating the duty cycle of the LED. As the battery voltage falls, the LED is left in its "ON" state more often. This provides a constant brightness.

3. Battery Indicator: By holding the button for three second the headlamp displays a battery level indicator. It flashes four times either all white, all red, or somewhere in between.
4 white= 100%, 3 white/1red = 75%, 2 white/2red = 50%, and so on.

4. The boost mode! You can get up to 70 hours of light if you leave the headlamp on dim. The HB LED can really drain battery quick. The solution is a second button that boosts the headlamp up to full brightness for 1 minute and then slowly fades back down. Your eye adjusts so you hardly realize the dimming and then you are back on the dim mode. You can also set it to bright but be warned if you forget it on this mode you can burn through the battery in less than 2 hours.

If you look at the page, be sure to look through some of the updates for other info. And if you have any other questions please send me a message. I've been trying hard to respond to everyone.

Thank you all again,

(Joomy) - M
Backed on 05/28/2012 21:18:51 MDT Print View

Looks great. Backed.

/A .
(biointegra) - MLife

Locale: Puget Sound
Re: DIYed headlamp on Kickstarter - Bosavi on 07/28/2012 16:03:48 MDT Print View

Bummed I missed it, but I signed up for notice on the website here:

Hopefully they will make it to production soon. Great job, Dan.