What DIY voltage regulator for DIY bike lights???

It seems I will have to go with the Lightbrain DIY project. What drives me
crazy is the fact that he does not provide the PCB layout for the new one.
The old one is simpler, and has the PCB, but that one works with 12V, and he
does not hive the instruction on how to tweak it for 7.2.

Darn - always problems

Domi

On Mon, 28 Nov 2005 12:48:36 -0800, SMS wrote:

It appears that these need to be customized via the firmware, which
makes such distribution difficult, though a board that took an input of
22-30V, with outputs of 14.4, 13.8 13.2, & 12.0 volts, and a board that
took an input of 11-15V with outputs of 7.2, 6.9, 6.6, & 6.0 volts would
cover the bases for bicycle lighting, including 10%, 15% and 20%
over-voltaging. There might even be enough GPIOs on the microcontroller,
that it could be user customized with jumpers.

Better yet, solder bridges. You're gonna be soldering wires to them
anyway.

Given that this regulator very specifically needs a lower voltage bulb
than the battery, I'd say what you'd need first was one suitable for a
4.5V or so bulb with 6Vnom generator/6Vnom battery.

I wonder if he's considered marketing them as a Mag Lite option. 3D
maglite with 2D bulbs, or some other combination. You would have to design
a replacement switch assembly, but it should be possible to cram the small
board, or at least a redesigned version of it, into that space. At least
on the D-cell mags. For the Cs you could go with an assembly that's
C-size. So 4C mag with 'battery' plus 3 C-cells plus a 2 cell bulb.


Jasper

Jasper Janssen wrote:
On Mon, 28 Nov 2005 12:48:36 -0800, SMS wrote:

It appears that these need to be customized via the firmware, which
makes such distribution difficult, though a board that took an input of
22-30V, with outputs of 14.4, 13.8 13.2, & 12.0 volts, and a board that
took an input of 11-15V with outputs of 7.2, 6.9, 6.6, & 6.0 volts would
cover the bases for bicycle lighting, including 10%, 15% and 20%
over-voltaging. There might even be enough GPIOs on the microcontroller,
that it could be user customized with jumpers.

Better yet, solder bridges. You're gonna be soldering wires to them
anyway.

Given that this regulator very specifically needs a lower voltage bulb
than the battery, I'd say what you'd need first was one suitable for a
4.5V or so bulb with 6Vnom generator/6Vnom battery.

The reason I think that the 12-14.4V and 6-7.2V options would be good is
because the most popular commercial lights are 6V and 12V MR-11 and
MR-16 lamps. These are what most homebrew lighting systems use because
the lamps include a precision matched reflector, and the lamps are
available in many different beam spreads from narrow spot to wide flood.

I've seen 555 timers used as PWM dimmer and motor speed controllers, but
automatically changing the pulse width or frequency based on the
battery voltage would be less precise, though it can be done by using
the little-used Control pin on the 555.