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HexBright is a stylish, rugged, high-power compact light you can use as-is or reprogram however you want using open-source code.
HexBright is a stylish, rugged, high-power compact light you can use as-is or reprogram however you want using open-source code.
3,156 backers pledged $259,293 to help bring this project to life.

FLEX Electronics Update 2

A brief update on V0.2:

The buck-boost converter is working beautifully! The LED driver was tested driving at two current modes 500mA (180 Lumens) and 2A (630 Lumens) over the full range of operating voltages (2.8-4.2V). There was almost no variance in current output, which means this driver will guarantee constant brightness over the entire battery life. V0.3 will have the current set at 350mA (100 Lumens) and 1.8A (500 Lumens).

The Buck-Boost driver has an enable line which enables/disables the driver and puts into a low current standby mode. This enable line can be PWM'd effectively to vary the current from 0-100% of each of the two settings (200Hz-2kHz). This proved to be very effective and there is no noticeable flicker even when driving it as low as 3 Lumens @200Hz!

As Christian mentioned in UPDATE #27 V0.3 of the electronics is in the works and more to come about that in the near future!!

Terry @ Hexbright.com


So to head off a few questions...

1) Why limit it to 1.8A instead of 2A?

A: Even at 1.8A the Buck-Boost driver has to mitigate tremendous amounts of heat through the circuit board. V0.3 will have a highly optimized heat transfer path for the Boost Converter. Proving the circuit at higher than design conditions incorporates a factor of safety into the design.

2) PWM only up to 2kHz?? Why not 20kHz??

A: There is a minimum time in which the boost converter needs to stabilize. This is not an issue however because even most sensitive of eyes cannot visibly detect flicker outside of 75hz. FYI.. most TV's update at 24-60hZ!! See the image below.

Comments

    1. Creator T TARARO on March 13, 2012

      hey mate , this is taking soooooo looooooong , when exactly do I get this thing??????? its almost 6 months after your original eta.......

    2. Creator Arun on January 9, 2012

      When are you looking to ship this out?

    3. Creator Scott on January 5, 2012

      Too late to cut heat sink fins into the body and maybe leave out the curvey shape in the foreward-most portion of the light? To leave a maximum ammount of metal in that region for cutting heatsink grooves/fins into? I was just thinking about the heat generated out of the heat sink of these LEDs and if light output and longevity may be affected because of trapped heat. Just wondering... Scott

    4. Creator Anthony Scalzo on January 4, 2012

      I agree with Michael Nunes I have a Surefire X300 and a new Milwaukee LED light that uses the same battery as the drills I have. I've got plenty to hold me over and it will be worth the wait. Consider me patiently excited. Maybe for a feature product I would love to have an option to tether the flex bright to an external power source while its running for continuous operation, I do intend to try mounting this light on my AR.

    5. Creator Michael Nunes on January 3, 2012

      3media,

      I think I'd rather have a finished product than whatever he may rush out just to satisfy you. 6mo-2yrs is really not long to wait when it comes to a custom flashlight...

    6. Creator 3media on January 2, 2012

      Question. When is an anticipated release date for these units?

      I know the level of "awesomeness" is worth the wait but, at some point, a product needs to be produced and shipped

      Having worked with engineers, this saying keeps coming to mind... "An engineer left on their own will never get anything done..."

      There will be rev 1.001, 1.001.1, 1.001.1.5, 1.001.1.5a, 1.001.1.5a RC 1, 1.001.1.5a RC2 etc...

      You've had the dough since July and frankly it's time for a product

      I'm not willing to wait a year for this

    7. Creator 3media on January 2, 2012

      Question. When is an anticipated release date for these units?

      I know the level of "awesomeness" is worth the wait but, at some point, a product needs to be produced and shipped

      Having worked with engineers, this saying keeps coming to mind... "An engineer left on their own will never get anything done..."

      There will be rev 1.001, 1.001.1, 1.001.1.5, 1.001.1.5a, 1.001.1.5a RC 1, 1.001.1.5a RC2 etc...

      You've had the dough since July and frankly it's time for a product

      I'm not willing to wait a year for this

    8. Creator Jonathan Goldsmith on December 29, 2011

      @JonB - I did not take the question to mean that 2kHz would be good enough. I took it to mean that it should be at 20kHz.
      @Martin P - A standard flashlight does not require that many components to be made. A standard flashlight is also not programmable, and also I am not talking about a non-LED flashlight. Even for LED instead of regular bulb, additional components have to be added(a resistor, I think?). A standard flashlight also is not programmable.

    9. Creator Martin P on December 16, 2011

      I still think this is awesome. Take as much time as needed to finish the thousands of flashlights. I don't mind waiting for this great product. I wouldn't have thought that you need that many components for a damn flashlight. Was it harder to design then you thought it would be?

    10. Creator stephen herbert on December 12, 2011

      which 18650 battery are you looking at using?
      i see panasonic has a 3100mah model, the battery itself is protected?

    11. Creator JonB on December 10, 2011

      @Charles- The analogy of using a TV for a flashlight misses the point as much as the refresh rate comparison does. Pretty sure they implied that 2kHz would be good enough, not 24Hz.

    12. Creator Charles Grant on December 9, 2011

      Flicker detectability is much greater when the light source or illuminated object are moving. Stating that "it is not an issue" and quoting TV refresh rates misses the point. Have you ever used a TV as a light source for moving objects? It doesn't work very well because of strobing. 120Hz, 240Hz and 600Hz TVs are built for real reasons (although not for use as flashlights) so implying that 24Hz is good enough for TV so it must be good enough for me is just wrong. That said, 2kHz is probably plenty for the vast majority of flashlight uses.

    13. Creator Richard Kimitsuka on December 8, 2011

      Will $90 backers be able to upgrade to (2) Flexes from (1) Flex and (1) Prime?
      I would be interested in upgrading if this is an option.

    14. Creator Nonolith Labs on December 6, 2011

      Any news on when you'll be releasing preliminary electrical designs?