Environmentally friendlier Cyalume(TM) substitute.

For the longest time, I've been searching for "the right" LED-based light stick that can be used in place of chemical light stick at Japanese-style concerts. I think I'm going to settle with these... for now.

They're Happy Camper LED Light Sticks. There's a link on that page, listing stores that sell them, so if you're interested, you'll be able to pick one (or many) up. Surprisingly, these are made in Korea, *not* China. And here I thought *everything* is made in China these days.

Here are some quirks with them, and how I worked around them.

• First, "yellow-green" actually uses a blue LED. With the green casing, it sort of looks like greenish yellow, but it's not as good as real green. I have no idea why they did it that way, but it's trivial to replace the LED with a proper green one, so that's what I did. In fact, since I was messing with them anyway, I replaced all of them with higher efficiency (brigher!) LEDs of correct colors.
• Red version uses two batteries whereas others use three. This is due to the lower forward voltage drop inherent in red LEDs. There's obviously nothing wrong with this as it actually saves you money, but I like consistency. I'm weird that way. Anyway, this leads to the real problem below.
• LEDs are driven directly from batteries without any circuit in between, not even a resistor. Battery's internal resistance is the only thing that's keeping the current in check. I measured over 40mA with fresh batteries. 5mm LEDs used in these devices are usually designed for 20mA continuous current. In reality, it's probably not a big deal for the LEDs themselves, but it's completely wasteful to be driving the batteries at full power. These little AG13 batteries have less than 150mAh worth of capacity. It's more likely to be around 120mAh. 40mA only gives you 3 hours worth of run time. Of course, as the batteries wear out, current will also naturally be reduced, but it doesn't change the fact that a lot of power is wasted in the beginning. Thankfully, there's enough room in the device to add a resistor. See images below for details.
• End of the sticks are clear and so the light has a tendency to get projected out the end, like a flashlight. It's not all that bright, but it's still bright enough to annoy anyone looking straight at it. Obviously, it wouldn't be nice to annoy the performer, so, I popped the cap and carefully put aluminum foil in it to block the light. It's somewhat shaped like a reflector, so it actually reflects the light back into the stick. Two birds with one stone!

I expanded the internal path for one of the LED leads, so that a resistor will fit in it. I used a 1/4 watt resistor because I had them, but 1/8 watt version should be more than enough, with the additional benefit of requiring smaller hole. Note the black dotted lines. Avoid drilling too deep, as you don't want to damage the exit hole for the lead. Beyond that, it just requires carefully soldering the resistor to the LED's shortened lead. I used 35-ohm resistor for green and blue. Green could've used 30-ohm, I guess. Current draw went to 18-21mA after the modification.

Here's a picture of the red one. I used a 90-ohm resistor for this one because I wanted to put the extra battery in there. Technically, I'm just wasting power through heat, but I like consistency. I told you I'm weird. If you want to stick with 2-batteries for the red, you can use the same 35-ohm resistor in this one, too. The key is to solder the resistor as close to the LED body as possible, without damaging either.

Here's a picture of the red version with another LED light stick. I got the one on the right for free long time ago when I bought stuff from cheaperthandirt.com. It's kind of basic, but it's got a very nice consistent glow to it. I'm keeping it around as a backup.

Here's a comparison between the upgraded Happy Camper Light Stick and a standard 12-hour Cyalume brand 6-inch glow stick. I put them on my photography grey card. It should be *obvious* that Happy Camper is much brighter. Note that I upgrade mine with 8000 mcd 30-degree LED. I believe even the stock LED would be brighter than Cyalume stick, but not quite as much. Also note that this Happy Camper will maintain the brightness for over 6 hours, with many more hours of useful output past that. I don't have an Ultra Orange with me, so I can't do a comparison there. If I feel like it, I can shove another LED in the stick to compete. This isn't a competition of brightness, though. After all, if it's too bright, it'll just annoy everyone around you and get in the way of enjoyment of the concert.

Here's another comparison shot, on black fabric. Again, it should be obvious how much brighter the Happy Camper is compared to the 12-hour Cyalume.

For orange version, I'm going to make one up by picking up a white stick and then putting an orange LED in it. However, pink is a bit of an issue. Pink LEDs currently available are not very sturdy. I'm going to try to make one at some point by putting a high-power red on the bottom, and then a weaker blue on the other side. I think I can get something working for pink (or close to it) one way or another.

Which brings us to Ultra Orange. As far as I know, there is no non-exotic orange colored LED bright enough to compete with UO stick, by itself. Well, if one is not enough, how about 2, 3, or... nine of them?

It's hard to take a descriptive picture of a glowing object by itself because it tends to saturate the digital camera's sensor. This one shows it lighted up at slightly less than ideal current of around 16mA per LED. I'll shoot for 20mA per LED on the final version, of course.

Here it is inside an empty 6-inch Cyalume(TM) casing, next to my upgraded Happy Camper Red. Remember, this Happy Camper stick is already brighter than a regular 12-hour or 6-hour Cyalume(TM) stick. Also note that the orange light has already saturated the camera's red sensors. The real question is, how does it compare with an Cyalume(TM) Ultra Orange? I don't have one with me at the moment, so I can't make the comparison.

Also, there's no way to drive this many LEDs using the LR44/AG13 button batteries. My plan is to use a single Lithium-Ion 14500 (AA-sized) 3.6V cell. It's going to be embedded inside 12-inch Cyalume(TM) casing, cut down to about 8.5-inches, with Micro Deans connector sticking out at the bottom. If you're familiar with R/C (Radio Control) airplanes, you've probably heard of Deans connectors. Anyway, this design is definitely not for everyone because Li-Ion batteries require special handling. It should be able to run for about 4 hours on a full charge. As a bonus, it's rechargeable!

In conclusion, these are sized just right (comparable to 6-inch Cyalume), *very* light weight, quiet (no broken glass slushing around), decently constructed, bright enough with long battery life, and hackable enough to allow me to fix up some flaws with them. With some additional work and specially made Ultra Orange replacement, I think I'll be all set for practically any concert settings.

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