H&M Contest Class 2 Entry: The LightPipe

Here is my Class 2 entry: The LightPipe (I'm not too fond of the name).

Here it is next to a modded 2D mag:




This is an MR16 based light, built into a section of 2" schedule-40 PVC pipe, with low-profile endcaps, and a rocker power switch.

The bulb is a 35W, covered, 12 degree MR16 bulb.



I needed a portable 12V power source. The bulb draws 35W at 12V, so the power source needs to be able to supply 2.8A of current. I wasn't about to torture any of my AA batteries with such a task, so I built this battery pack:



That's a 12V, 3Ah, SubC NiMH battery pack (10 cells). I made it by combining two 7.2V RC racing packs. It's zip-tied to a piece of board (underneath the pack), to give it rigidity, and center it within the body tube. I should get an hour of runtime with this battery pack.



Here's the bulb holder and the cross piece I made to mount it within the pipe. With this setup, I can drop any MR16 bulb in here. With a 20 watt bulb, I can get almost 2 hours of runtime. There are a wide range of MR16 bulbs. So I could stick a 20W flood, or a 50W, 8 degree spot bulb in here for different tasks.


BEAMSHOTS!!!! /ubbthreads/images/graemlins/grin.gif

Here, the LightPipe is compared to the 5W Mag mod in the first picture. The 5W is a V3T at 1A. 5W on the left, LightPipe on the right.

First, the corner of my garage, about 32':



Next, the door rail at about 24':




The 5W is throwing out about 120 lumens, while the LightPipe, supposedly about 700 lumens.



Of course, a big battery pack needs to be charged. I didn't have a charger capable of charging a 10 cell pack - so rather than go buy one, I decided to build one instead (it's an engineer thing).



This is a Maxim Max712-based NiMH charger. It's set for 1A charge current. The switch allows me to switch between 6 and 10 cells, so I can charge those 6AA packs all at once, rather than swapping out batteries 4 at a time.

So, can anyone think of a better name for this thing? /ubbthreads/images/graemlins/tongue.gif

BTW - ignore the red Xs for now, my web host is broken again (and this is one I pay for /ubbthreads/images/graemlins/mad.gif )

In a word: awesome... that thing is 'the bomb' which coincidentally... since it looks like a 'pipe bomb' maybe light bomb might be a cool name considering HOW MUCH FREAKING LIGHT that thing puts out.. hand out some solar shields before showing that to people... very cool.

Now you got me thinking... hmmm. since my battery pack can handle 200W... i could have gone the incandescent route and plugged 3 of these bulbs into my light and... 2100lumen? of course that would only last 30 minutes or so but wouldn't that be fun? /ubbthreads/images/graemlins/wink.gif

great! and the name is ok, too, it's just a bit less cool /ubbthreads/images/graemlins/cool.gif than the actual light, which is a bomb!
/ubbthreads/images/graemlins/thumbsup.gif
bernhard

Thanks, I wish the pictures were showing up.

I discovered something disturbing last night - after about 5 minutes of constant running, little whiffs of smoke came from the light. Apparently, PVC has a low melting temperature, and the MR16 bulb gets REALLY FREAKING HOT!

I think I'm going to rebuild this, instead using 2" copper or aluminum pipe. No big loss, as everything else will transport over, and the PVC body parts cost me about $2.

Anyone know the rules for the H&M contest about modifying entries? Is that legal, and just has to be done by Jul 17, or does it count as a new light?

Evan,

I think the "rules" were intended to be flexable. Maybe you could unenter this version and make a new entry with the moded "mod." Modding the mod within an entry is fine too. Your choice. /ubbthreads/images/graemlins/smile.gif The contest is really about the lights with their accompanying threads.

Larry

tvodrd,

Cool, I think I'll update the pictures when I get it a new body that won't melt after 5 minutes, that'll be the "final" version.

Pictures appear to be back.

Yep, the PVC starts melting. I had a 75 watt bulb (car driven) in a pvc shell. Did the same thing.

Your light looks fairly yellow. It is because you are running it with 10 cells. You should have kept the 2 7.2 volt packs and gone with all 12 cells. That will "properly" drive the bulb. MR16's have something like 2000 hour or more bulb lifes. Run them at 14.4 and you reduce this to 100-200 hours, which is still PLENTY. The upside is you will get a LOT more light. I would say your light is probably 500-600 since it probably isn't QUITE receieving 12 volts from a 12v nominal pack. Run it from 12 cells and I'd say you'll get above 800 lumens, and if you had osram decostar IRC bulbs (dang hard to get here, I STILL wish I had a couple, a 35 and 50 watt) you'd be probably over 1000 lumens.

Actually, the bulb is getting full voltage - I just measured it, 12.65V. Remember, these are SC racing cells, designed to deliver high current, so there is very little voltage drop under load. Also, fresh rechargables have a terminal voltage of about 1.35V/cell

The bulb looks very yellow because I locked my camera's white balance to daylight - I find this achieves the best balance when comparing lights - LEDs don't appear too blue/green, and incandescents don't appear too yellow.

how about calling it the HaloPipe? you know, HALOgen PIPE

neg