Megasonic 12W Luxeon

The new face of Megasonic.



before:


after:


I finally got my upgrade and just in time for laborday weekend (camping trip with the family... there is always a face-off of portable lighting).

Anyhow, since the design stage of Megasonic, I had intended the possibility of an upgrade to more emitters.. (4 or 6 being the highest probability)... After some deliberation i decided to go with 4 with an 'ace'...

Went with 4 because the buck puck driver i'm using can just barely handle 4 emitters at nearly max power.. at fully power they are drawing a total of 880mA at 13.3V.. or 11.7W... apparently getting near the limits of the driver, because i can get over 3W/emitter with 3... however saved $25 only using one more emitter 'cause no add'l driver needed.

The ace, you might ask.. picture worth at least a dozen words... rather than using the awesome but small S017XA reflector, i opted for the S027XA... and to quote monty python.. "you chose wisely"... I couldn't be happier.. i wouldn't want to have all 27s but having (3) 17s and (1) 27 works perfectly..

Initially though bright as the sun (pretty much literally)... the center was a pretty bright flood, but some bright incandescents i went up against (namely a 14.4V dewalt light and an 18V crafstaman light) had a brighter hot spot (even though they sucked as a work-light in comparison... spotty, ringy)..

Well I was not going to stand for my brother's 14.4V light bein' brighter... so i ordered up the parts and upgraded my 9W megasonic to 12W... however with the 27 in there... BANG this thing is bright.. can't wait to do a test with a light meter.

After the upgrade... ended up with a problem.. perhaps due to the new power levels.. there was a turn-on voltage spike that would sometimes cause the voltage checker to think the battery was dead and it would blink and shut off :-(... after taking apart the 'sonic and measuring here n there with the precious fluke 87 (can measure a 1ms spike).. it caught the reference voltage from the buck puck spiking to 5.5V, which made my halved reference spike to 2.75 and is supposed to be 2.50. Since i reference that up to 14V to turn off the light, the cut out voltage went from 14.0 to 15.4V, and when the battery is only mostly dead (princess bride fans out there?) it would shut off... but if it turned on, it would stay on 'cause the spike only lasted a few milliseconds.

I only needed to add a capacitor to the leg of the op amp that was tied back to the reference (hysteresis loop) and the ref. voltage now sticks at 2.500, it was amazingly stable.

I had upgraded the switch a few weeks ago so i have a much better control and the dial also includes the switch.

Beamshots ya say?



Well that's one... It's about 15' to the wall.. notice how the entire room is illuminated from the bounce! To see the rest go to the Megasonic Webpage and click on the 12W upgrade

Adding my own reply... I forgot to mention... for a flat-heat sink like this design where there is no PCB to mount the emitters... the new design of the S0XXA reflectors sucks... it used to be a very simple thing to attach them and wire them up, now there is work involved.. the 17s might be sorta ok but the old can design was way better, not even the same ballpark.

The 27... while designed to work perfectly with the star, was sucky with the emitter, though i do like the look (looks like a rocket motor).. the wires are all visible and you have to mess around to make the leads not short out on the heat sink... with the 'old way'... you simply bend the emitter leads straight up... line them up with holes in the heat sink, and solder straight on.. the lead goes up into the 'can' and you can't see it and gluing the can down with silicone hides everything. Anybody have any of the 'good ole 17s'?

one more note: i didn't shave down the 27... that either made for a sharper or a softer focus on the center beam, 'cause it's designed to be over the star pcb from what i understand.. however i was very happy with the beam, and didn't want to risk making it worse by changing things... anybody played with the 27 and know the difference with the feet shortened... it didn't look like it would clear the leads if i shortened the feet was another reason i didn't go there.

-awr

Looks good. /ubbthreads/images/graemlins/thumbsup.gif

beamshots update...

I finally got to use megasonic for its original intended purpose: camping..

I took some nice sample beamshots and they are here

here is a sample image:



that's the 12W light... beaming down a gravel road.. the last reflector seen is on a car 65 yards away.

I made another wonderful addition to megasonic today... i cut circles using a quarter as a guide from the plastic i used earlier for a diffuser and placed them directly over the three small emitters... NOW i can simply turn the bezel 60 degrees and it goes from flood to spot.. it works incredibly well.

-awr