Now, for my latest creation....
BEHOLD!
(showing the carrying handle)
This is a fully adjustable, quad-luxeon camping lantern. Output can be adjusted from a dull glow to spot-inducing brightness, or anything inbetween.
It runs off 6-D batteries.
It is constructed from aluminium. The lower body is a 4.5" piece of 4" aluminium square tube, 1/8" thick. The top part of the body is a giant heat sink to keep the luxeons cool. It's probably massive overkill (more info about the heatsink below) - but IMO, you can never keep your luxeons too cool.
The luxeon stars sit on a pedistal that's attached to the bottom side of the heat sink. The pedistal is a 1" square piece of aluminium bar stock, 2.5" long. Here's a closeup of the luxeons:
There are two strings in parallel of two luxeons in series (series-parallel setup).
Here's where this thing gets its name - the heat sink:
It is a round pin-fin design, which works really well for any direction airflow, or still air. It has 48 pins, in a 7x7 grid - there is no pin in the centermost spot due to the pedistal attaching to the plate at that point on the underside
The heat sink starts out with a base plate of 3/8" aluminium, 4" square. Into that, I drilled 48 holes and tapped all of them. The pins are 1/4" aluminium, 2.25" long. They are threaded for 3/8" and screwed tightly into the base plate using some thermal compound on the threads to aid heat transfer. Overall, it took me about 12 hours of drilling, tapping, cutting, and threading to get this built.
The heat sink performs very well. I measured 1.5C/W in still air, 0.5C/W with a weak 80mm fan (~20cfm) and 0.3C/W with a huge 5" 135CFM fan. Given the paltry 7W (max) of heat this thing needs to dissipate, these luxeons will stay cool as a cucumber.
Here's the underside with the bottom cover removed.
There's an internal bulkhead that separates the battery compartment from the electronics. The 6D cells sit in a 2x3 battery holder. Pay no attention to the mix of Ray-O-Vac alkalines (blue/silver) and Sanyo NiCD cells (green) - I couldn't dig up 6 identical D cells...
You can't really see it, but the regulator circuit is stuffed in here. I'm using an LDO op-amp controlled linear regulator. Using the pot, the total current can be adjusted from 20mA up to over 1A. The current is split between the two luxeon series strings, so each luxeon gets from 10mA-500mA.
Some "beamshots" (not much of a beam since this is an area light)
20mA (lowest setting)
200mA
500mA
800mA
1A+ (highest setting)
Approx. REGULATED runtimes:
The 20mA level is perfectly acceptable for reading or finding your way around in the dark - and you get nearly 40 days of continuous light!
BEHOLD!
(showing the carrying handle)
This is a fully adjustable, quad-luxeon camping lantern. Output can be adjusted from a dull glow to spot-inducing brightness, or anything inbetween.
It runs off 6-D batteries.
It is constructed from aluminium. The lower body is a 4.5" piece of 4" aluminium square tube, 1/8" thick. The top part of the body is a giant heat sink to keep the luxeons cool. It's probably massive overkill (more info about the heatsink below) - but IMO, you can never keep your luxeons too cool.
The luxeon stars sit on a pedistal that's attached to the bottom side of the heat sink. The pedistal is a 1" square piece of aluminium bar stock, 2.5" long. Here's a closeup of the luxeons:
There are two strings in parallel of two luxeons in series (series-parallel setup).
Here's where this thing gets its name - the heat sink:
It is a round pin-fin design, which works really well for any direction airflow, or still air. It has 48 pins, in a 7x7 grid - there is no pin in the centermost spot due to the pedistal attaching to the plate at that point on the underside
The heat sink starts out with a base plate of 3/8" aluminium, 4" square. Into that, I drilled 48 holes and tapped all of them. The pins are 1/4" aluminium, 2.25" long. They are threaded for 3/8" and screwed tightly into the base plate using some thermal compound on the threads to aid heat transfer. Overall, it took me about 12 hours of drilling, tapping, cutting, and threading to get this built.
The heat sink performs very well. I measured 1.5C/W in still air, 0.5C/W with a weak 80mm fan (~20cfm) and 0.3C/W with a huge 5" 135CFM fan. Given the paltry 7W (max) of heat this thing needs to dissipate, these luxeons will stay cool as a cucumber.
Here's the underside with the bottom cover removed.
There's an internal bulkhead that separates the battery compartment from the electronics. The 6D cells sit in a 2x3 battery holder. Pay no attention to the mix of Ray-O-Vac alkalines (blue/silver) and Sanyo NiCD cells (green) - I couldn't dig up 6 identical D cells...
You can't really see it, but the regulator circuit is stuffed in here. I'm using an LDO op-amp controlled linear regulator. Using the pot, the total current can be adjusted from 20mA up to over 1A. The current is split between the two luxeon series strings, so each luxeon gets from 10mA-500mA.
Some "beamshots" (not much of a beam since this is an area light)
20mA (lowest setting)
200mA
500mA
800mA
1A+ (highest setting)
Approx. REGULATED runtimes:
Code:
20mA 900 hrs (37.5 days)
100mA 150 hrs (6.25 days)
200mA 70 hrs (2.9 days)
300mA 45 hrs (1.9 days)
400mA 30 hrs (1.2 days)
500mA 21 hrs
600mA 15 hrs
700mA 12 hrs
800mA 9 hrs
900mA 8 hrs
1000mA 6 hrsThe 20mA level is perfectly acceptable for reading or finding your way around in the dark - and you get nearly 40 days of continuous light!
and diffuse the light...
48 hand drilled and tapped holes and 48 hand cut and threaded rods ! This could be a shop class project for a whole semester :lolsign: 
