About tzf

Tim Z Falconer founded Luma League in 2011 after starting the project as a blog to show how to easily make a bili light. Luma League equipment now is in use around the world. Our mission is to bootstrap local tinkerers into locally innovative production by jumpstarting high-added-value local manufacturing via the use of Luma League kits.

Cones of Blue Light


I’ve been working on the new model of bili light, and got into modeling the cones of light that the LED’s, with their lenses, produce. I came up with four images showing the Luma League 120×5 model – the one that has 120 of the 5mm Cree C503B-BAS LED’s:

C503BAS 5MM X 120 PRIMARY LENS AT 19 INThis lovely thing shows the coverage of all 120 LED’s and how the cones line up… but what are we seeing exactly? How many are showing in any one place?




C503BAS 5MM X 120 PRIMARY LENS AT 19 IN v2-WEB PNG -4cornerI figured that was worth some more investigation, so I created this image, showing how the cones from the four LED’s on the outside corners hit a target at 19 inches (the nominal distance for treatment). As you can see, there is a diamond-shaped zone in the middle – that is an area where all 120 cones from all 120 LED’s will shine.


C503BAS 5MM X 120 PRIMARY LENS AT 19 IN v2-WEB PNG -4centerThis image shows how the cones from the four center corners line up, when the LED’s are arranged as we normally do, with three rows of 10, and then a gap in the middle for wiring, then another three rows of 10 LED’s. The two groups of 60 show the two circuit boards that are standard on this model.


C503BAS 5MM X 120 PRIMARY LENS AT 19 IN-4corner-center-isoFinally, here’s a pair of views from the top – or the bottom – showing the same patterns as the previous two images.





So, you can see that there is a small area where the light from all 120 LED’s shines, and then offset areas where two less or four less LED’s shine, all the way to the edge, where the light falls off dramatically.

Note, these cones are the “FWHM” cones for this model of LED, the Cree C503B-BAS. That means that the light falls off by “Half Magnitude” at the edge of the 15-degree cone, and continues, in this model, to fall off to about 10% in another 15 degrees (30 degrees solid angle). So even at the center where the overlap is, the power is not the full power of 120 LED’s, and even at the edge where I show the dropoff to zero, it’s not quite that extreme of a dropoff either.

(please see the Cree data sheet here for more detailed information on these LED’s)

Kenya Connections


A month ago, I reached out to a local Rotary Club in Fremont. I drive past Fremont on my way to work every day. It was a funny coincidence, actually…

I wanted to write a blog post about Blue Bells Orphanage and could not remember the name of the town or area where they are, so I opened up Google Maps and searched for “orphanage western kenya”. The map zoomed RIGHT IN on Niles Rotary Club in Fremont!  …I said “well, that’s funny” and looked up their web page. It turns out that they have sponsored trips to orphanages in Central America (I forget where, Guatemala?) and also, one member who is an MD makes frequent visits to Western Kenya… so that’s why it turned up in my Google Maps search.

I sent messages and eventually talked on the phone with Manuel and with an MD, Dr. G, the guys from Niles Rotary Club. They’ve invited me to visit, and when I get the new prototype bili light finished, I will go and show it off.

I asked them both about working with Blue Bells, and they repeated some advice that I had gotten from others in the International Health world: don’t get caught up with people who need far more than you can offer. All along I’ve had concerns about Blue Bells:  in the past I have always sent bili lights with MD’s to hospitals where I know they will be used properly. There is a danger with anything you send that instead of helping, even with the best intentions, it will inadvertently delay professional care for a newborn who should be in a hospital. But the descriptions I had gotten from them were not hopeful- it did not sound like the kind of place that would be able to successfully diagnose and treat a baby with acute hyperbilirubinemia.

But I’ve been shy about grilling Chrisphine, the director of the orphanage, to ask him directly – how can I be sure you’re for real? How can I know that this bili light will be used properly?
I was hoping that Dr. G. from Niles Rotary could visit the orphanage, and that may still be a possibility. He’s going to western Kenya in January, and it turns out that his destination is rather near to the orphanage location. But being in touch with Dr. G also means that I don’t want to waste his time – or worse, to send him into a bad situation. So I finally figured out that I just have to ask Chrisphine the hard questions and see how he reacts.

As it turned out, he reacted perfectly, and told me details about the hospital where Dr. Caroline works. Dr Caroline is a Kenyan doctor who I’ve had contact previously, and I think it was through her that I got in touch with Blue Bells. I don’t know why they had not told me about the hospital before, and it’s certainly not a large or well-staffed place by Western standards, but it has a staff of 4 MD’s and 6 nurses, and there are 130 beds. That’s not a great ratio, but it’s apparently a real place. When he told me where it was, for a few minutes I thought it was the very same hospital that Dr. G. is involved with… I emailed him, and it turns out that it’s not, but his hospital is in the same general area – it looks like it’s probably within 20 or 30 miles.

So, I’m making arrangements with Dr. G to have the bili light delivered in January… or so. Dr. G may not have room for the bili light himself, but apparently he’s got his finger on the pulse of a stream of people who make trips to that area. And as you know, my bili lights are small, so I’m guessing once they see them, they’ll be able to see that they do have room to take one along.

Firefly at World Maker Faire and some good stats!


Congratulations to Firefly, who won the Pitch Your Prototype competition at World Maker Faire in New York City this week. The Firefly bili light is a beautiful design that they have obviously worked long and hard to achieve. It’s great to see the problem of neonatal hyperbilirubinemia in the Developing World getting the attention it deserves.

Most fascinating to me, though, were the statistics listed in the article:

[…] every year 5.7 million jaundiced newborns in South Asia and Africa do not receive any phototherapy.

I assume this quote was supplied by the good folks at Firefly. It was misquoted in the Maker Pro article (which left out the word “jaundiced”), but even more interesting once I found the source on Firefly’s Index: Awards nominees page. I checked some facts on the UNdata web site, and I’m not sure it’s correct. If it is, that does not mean that 5.7 million would die without treatment; it does not even mean that they would suffer irreparable harm. But here in the developed world, anything more than the most mild case of jaundice is treated with a bili light. Bringing the rest of the world up to that standard would save lives and reduce the number of people suffering the ill effects of jaundice, which include the form of brain damage called Kernicterus. The article continues:

Global health experts estimate 6-10% of all newborn mortality can be attributed to jaundice and complications caused by jaundice.

Is this a world-wide figure? I have often noted that bili lights are ubiquitous in the developed world, so I have to guess that most of those deaths occur in places where they don’t have bili lights. I found an incredible resource, a spreadsheet of neonatal mortality in 1990 and 2009, which makes some further analysis possible. If I’m using the data right, it looks like there were about 3.2 million live births in Africa in 2009 (and after cross-checking with the UNdata, that does appear to be correct). Out of those, the average neonatal mortality rate was 34 to 36, meaning 3.4% to 3.6% of those babies died in their first year of life – more than a million babies. If 6% of those could have been saved by bili lights, that’s sixty thousand babies.

The average bili light treatment for a neonate is 48 to 72 hours, so sixty thousand babies would need (at 48 hours of treatment) at least 120,000 days of treatment. If each bili light were running 24/7/365, then we would only need 329 bili lights to treat all of those babies – in an ideal world. It’s probably more realistic to give them a 50% utility rate (though I’ve heard that some of my bili lights have been used more like 80% of the time.)  To get to the point where no baby’s brain is damaged by the lack of availability of a bili light, you will have to have enough capacity to meet the peak demand at each hospital and clinic, so the percentage of time each one is used will be less as they become more ubiquitous.

If we max out the numbers, 10% of neonates get 72 hours treatment each, and 50% utility rate, I get 1,645 bili lights for Africa. Now, as I said above, only a certain percentage of the babies that really should be treated for jaundice will die without treatment – but many more will suffer kernicterus and other complications; complications that may not be life-threatening, but are better avoided, especially when jaundice is so easily treated. So maybe 10% of the neonates need bili lights to survive, but another 20% (this is just a guess) would benefit from them: 30% total, almost 5000 bili lights.

So: low end: 658 bili lights, high end, 5000 bili lights. Let’s call it 3500… Let’s call it 3500 and keep in mind that I’m just guessing at one of the factors.

It’s stunning to think that Africa could be saturated with bili lights if we could only get 3500 of them on the ground there! In terms of production, that’s an achievable goal!

Obviously, a lot of things will have to change before we can reduce jaundice deaths to zero – it’s not just a matter of making a lot of bili lights. Babies with severe jaundice need to be under a physician’s care, and physicians need facilities in which to care for their patients. I can do little to tackle these larger problems, but it’s encouraging to think that the basic goal of producing enough bili lights can be met so easily.

(this is version 2 of this article; the original version suffered from the mistake in the quote from Maker Pro. When I came back to edit, I added the number of lights for the babies that are facing not death, but permanent ill health effects. – tzf)

Blue Bells and new technology


I was contacted more than a year ago by Blue Bells Orphanage in western Kenya. The communication with them has been sparse, and when they first contacted me, the orphanage did not have electricity. There is a Dr. Caroline Anyango Odwaro who contacted me and recently got back in touch. She’s apparently in charge of a clinic attached to the orphanage. Now I have a new challenge: I’m done with soldering hundreds of 5mm LED’s to make a light that works, but is certainly inferior to the technology that is not just available, but affordable today. So, I’m working on a new model based on 3 watt LED’s from Cree.

At the same time, I sent the last bili light meter off to Soddo Christian Hospital – I have one meter that I’m keeping to evaluate and calibrate new bili lights, but I don’t have any more to send out. The meter is a more complex product and one that requires a special part – the special photo diode that has a built-in filter so that it reacts to 470nm light, the SLD70E470. I’m out of them and they were a bit hard to get – it was a special order and 6 of them cost me $40. Now I have two questions: one, is it worth it to continue building bili light meters, and two, will the meters be accurate with the wavelengths of light coming from these new 3W LEDs?

The new LED’s produce a slightly higher wavelength than the 5mm LED’s.  The 5mm version produced light centered on 470 nm, which just happens to match the center frequency of the SLD photo diode. The 3W LED’s seem to generally produce light around 455 nm. In terms of efficacy of treatment, this should work better than 470 nm light, since the ideal absorption wavelength for bilirubin seems to be 458 nm (from one of my sources on the topic, the only one that is specific about the wavelength). So the problem is not the efficacy of the treatment, but the ability to calibrate the meter properly to measure the dosage properly.

It’s not impossible, but direct analysis is probably not an option without support from Minolta or someone like that. I can probably get the data from both manufacturers (Silonex, the makers of the photo diode, and Cree, the makers of the LED’s) and compare the power curves and make a few reasonable assumptions. But the scientist in me wants to see direct measurements of the light, to be able to compare it to the readings on my home-made meter, to be sure that the new lights work at least as well as the older ones.

I have not promised that I will be able to send a bili light, with or without a meter, to Blue Bells in September. But having another “client” who needs a bili light has inspired me to start some long-overdue explorations into 3W LED technology.

Technology Marches Forward


It’s been pretty obvious from the start that the 5mm “bulb” LED is not actually the ideal part to use, in this day and age, for making bili lights. But as I said in a previous post titled Project Appeal, way back in July 2011 when Luma League had not even shipped the first 5mm LED-based light yet, the 5mm approach has a set of benefits that go along with the 5mm LED’s; namely: the 5mm LED’s cost less than $0.20 each and they’re fun to solder. The circuit boards are cheap too, we buy the copper-clad project boards for about $2 each. And soldering 120 LED’s and 60 resistors is a lot of opportunity for a lot of kids to do a lot of soldering and have a lot of fun.

On the other side of the equation is the modern SMD – Surface Mount Device – High-Power LED. While the 5mm LED’s consume 20 mA (milli-Amps) and turn that into blue light, modern high-power LED’s turn at least 350 mA into light, and with the new XT-E LED’s from Cree, some can do more than 500 mA. And they’re more efficient than the 5mm type, so they produce a LOT of light.

Today, I’ve been in touch with Cree, and I’m hoping to get some samples of their new Royal Blue XT-E led’s from them. In quanitity, they cost about $1.50 each, but so far, the smallest minimum order I’ve seen is 450 units… out of my price range for now. They also sell star boards that hold one XP-E or XT-E LED for about $1.10 each. So I might be able to solder together a high-power LED star board for as little as $1.60, as opposed to the retail price of about $4. That’s a big difference.

Today I also ordered a couple of pieces of MakersLED extruded aluminum LED housing from LEDSupply. I’ve not been happy with LEDSupply’s customer service in the past, and their prices are high, but this stuff is very cool, and I want some, so I ordered it. It has T-shaped slots to receive fasteners, and the slots are spaced to make it easy to position star boards on the bottom face. There are six T-slots giving you five tracks along which to attach star boards. The design is cunning in other ways too, and they’ve come up with a very intriguing range of accessories to finish, hang, and cool the aluminum and the LED’s attached to it.

Between the XLamps and the MakersLED extruded aluminum, we can come up with a very cool new design for bili lights that will have as much project appeal as the 5mm LED based design. It will not be a platform for a lot of practice soldering, but it will be fun and easy to put together.

New friends in Ethiopia


Seven weeks ago, I got an email via the contact form here on Lumaleague.org from a doctor working in Ethiopia. Tonight, I boxed up a bili light, a meter, a couple of power supplies, and a 9-volt battery to send to them.

The doctor is David Ayer, and the hospital is Soddo Christian Hospital in Soddo, Ethiopia. David’s put me in touch with two other members of the organization, and I believe that the bili light will arrive at the hospital some time next month!

In the mean time, technology has advanced rapidly, and I’m looking into producing a new, much more modern bili light for my next project. Stay tuned, I promise to blog a little more frequently than I have!

Thank You Maker Faire!


Luma League had a great time at Maker Faire Bay Area 2012. Here we see the results of two days of the “Save a baby – help Luma League MAKE a bili light” demo.

Teacher, Student, Solder, Pliers

Special thanks to our

Luma League VOL-LUMA-TEERS ! 

  • Shumit !
  • Penny !
  • Molly !
  • Art !
  • Zan !
  • Kimbrough !
  • Michael !
  • Sayuri !
  • Leona  ! (pictured here)
  • Dante-Luc !
  • Sven  !
  • Addison !
  • Alejandro !
  • Kai !
  • and last but not least – my mom- Karin !

Also a big shout out to SF Brightworks for their support !

Though these boards will need to pass through Quality Assurance, LED’s installed by visitors to the booth will be making their way to Haiti and D.R. Congo within the week!

bili lights made by Maker Faire people! Maker Faire!

bili lights made by vistors to the Luma League booth at Maker Faire!

Please visit our DONATE page to help Luma League cover the costs of the Maker Faire Booth and make it possible for us to continue our efforts.

Then, take a look at the new Photo Album from Maker Faire and see exactly how much fun we had at Maker Faire!