1. Light Therapy Overview & Introduction
Sunlight simulation and light therapy light boxes are commonly used as light therapy for treatment of Seasonal Affective Disorder (SAD). My mom has SAD and after seeing her wimpy light box I thought there had to be something better out there, after some research I was really surprised at the underwhelming sunlight simulator light therapy options on the market. When I started this project my parents lived in the Northern Virginia \ DC area of USA where there are many overcast days in the winter months. I love bright work lighting and lighting in general so part of me was happy that was not there was not a good option available on the market so I could be creative and make my own for her. Most light therapy boxes use fluorescent lighting which I have never liked due to its spikes in a few bands on the spectral power distribution (spectral distribution or emission spectra, discussed below). I love the full spectrum light of incandescent and halogens but to get a light bright enough to work for light therapy I needed a bulb in the 1100 watt halogen or 1500 watt incandescent range at minimum (likely much higher for ideal lumens) which is impractical in its power consumption and heat output. The best all around option is a high intensity discharge (HID) light such as a ceramic metal halide which have some of the best Color Rendering Index (CRI), spectral distribution, lifespan, and cost of any non-incandescent light source.
When picking which light source to use for a light therapy box build it is worth noting the other options other than fluorescents and why I did not choose to use them. First LEDs; the LED market is changing so quickly that whatever I say about the current LED options here will shortly be obsolete. When I started this project in 2013, high end, high power LEDs with very good spectral distribution were exponentially more expensive per lumen. To build or buy a high quality LED lamp that outputs 15,000+ lumens would use multiple extremely expensive high power high CRI LED modules and would actually be less efficient lumen output per watt than ceramic metal halide in 2013. Also LEDs have higher output in the blue spectrum than metal halide which is less natural compared to sunlight. LED technology is changing quickly and with time LEDs will likley overtake ceramic metal halide as the go-to choice. The second option was arc lamps like xenon arc or similar. While this is a very appealing lamp in terms of its emission spectral distribution characteristic (just about the best it gets and why they are commonly used in video projectors), metal halides are better from a practical and value standpoint. Xenons arc lamps have short bulb lifes (about the same as an incandescent), are very expensive compared to metal halide, output large amounts of UV, have relatively low luminous efficacy (~40lm\w), and ballast are much harder to find and are more expensive. If money was no object and heat was not an issue a well engineered xenon arc lamp would be the best option.
Metal halides are rarely seen in residential \ consumer lighting mainly due to their long startup times and higher prices but are the logical choice for sunlight simulation when startup times are not critical and will be turned on for long periods of time. Ceramic metal halide lamps are superior over traditional quartz metal halides due to their higher CRI and luminous efficacy which is obtainable from higher internal temperatures. When picking a metal halide bulb for a DIY lighting project there are some important things to keep in mind. Most bulbs are not rated for open enclosures and need some form of protection from a bulb blowout. This and all the bulbs specifications are listed in the bulb choices section. To give some background on what all the terminology is in the bulb comparison table, I have discussed a few keys points in the below section.
2. Terminology, Photometrics
I will not spend too much time discussing this because frankly Wikipedia and other sources do a better job of explaining it than I can but I wanted to explain a few of the terms used in this post. First here are some quick definitions of the terminology used when specifying a light source.
– Color Temperature: The temperature at which a black body would emit electromagnetic radiation of the same visible color as a given object. You can think of this as an indicator of how “warm” (yellow, orange, red – lower numbers) or “cold” (blue – higher numbers) the color of the light output is. This is complicated by the fact that many light sources (including fluorescent, metal halide, and LED) primarily emit light in a process other than thermal radiation which does not follow the form of black body radiation. This is corrected for and as the emission color of a black body that is perceived to be the same as the emitted light under test, you will sometimes see this color temperature listed as correlated color temperature (CCT).
– Color Rendering Index (CRI): The ability of a bulb to reproduce the colors of various objects in comparison with daylight. It is important to note that there are different standards for measuring this. A high CRI does not always correlate with how you perceive the color rendering quality of a light source, the color temperature of a light source plays a key role in this.
– Spectral power distribution: Light consists of electromagnetic radiation of different wavelengths. Each wavelength has a different intensity which can be measured with emission spectroscopy to create a spectral power distribution (SPD) curve. When combined with all other visible wavelengths emitted by a light source, this determines a light source color, color temperature, and CRI. Spectral power distribution is sometimes called emission spectra or emission spectrum.
– Lumen: Measure of the total amount of visible light emitted by a source.
– Lux: Luminous power per unit area, not the total light output of a light source, but the amount of light in a defined area, for example, a one meter square. A flux of 1000 lumens, concentrated into an area of one square meter, lights up that square meter with an illuminance of 1000 lux. However, the same 1000 lumens, spread out over ten square meters, produces a dimmer illuminance of only 100 lux.
3. Light Therapy 10,000 Lux Misnomer and Ambiguity
The gold standard in light therapy lights is 10,000 lux but this is a very misleading figure given without other critical measurements. 2,500 lux to 10,000 lux is stamped on almost all light therapy lights from a few watt LED lights all the way up to the multi-bulb fluorescent fixtures. As mentioned in the terminology section above lux is a measurement of illuminance per unit area so unless the distance from the light source to where the measurement was taken is also given, the lux rating should be disregarded. Many products are purposely misleading customers, leading consumers to believe their product produces enough light for effective light therapy. The manufacturer can just place the light meter at point blank on the bulb to achieve the desired 10,000 lux reading. I have also seen references online to 10,000 lumen, this is also incorrect as lumens is a measurement of the total light output by a light source not the intensity at a given distance from a light source.
I built two lights, a directional and a omni-directional light. The directional light has roughly a lux of 10,000 @ 20″, 5,000 @ 28″, and 2,500 @ 48″. The omni-directional light has a lux of 10,000 @ 15″, 5,000 @ 21″, and 2,500 @ 32″. If I bounce the directional light off the ceiling it produces an ambient room lighting level of about 500-1,200 lumens in a small room depending how close to the light you are which works well if left on for a few hours a day. The measurements were taken with a Sper Scientific 840022 broad range lux/FC meter.
4. Spectral Power Distribution of Common Light Sources
This section breaks down visible light into the individual wavelengths of electromagnetic radiation (colors) we see. Looking at what frequencies of the light we see is comprised of, gives a better understanding of why some light “feels” or seems “cleaner” than others. It was hard to find the emission spectra of different light sources graphed the same way using the same scales. I may build a spectroscope sometime in the future to illustrate this better but for now what is important in the illustrations below is to look at the difference between the highest peaks and the lowest valleys, not how high the wavelength peaks. I have modified some of the images below to try and make the differences between the light sources more clear. What I like most about ceramic metal halide over all the other gas-discharge bulbs is its emission spectra. Ceramic metal halide emission spectra gives the closest match to daylight in its emission spectra. This all becomes clear when you look at the emission spectroscopy of common light sources below.
4.1 Sunlight (Full Spectrum Light)
Sunlight emits its peak power of radiation in the visible spectrum of light, i.e. the part of the electromagnetic spectrum that is visible to humans which is a wavelength of 390nm (violet) to 700 nm (red). We have evolved to see the sun’s electromagnetic radiation in the region of radiation that is most intense as this prolongs our vision longer into the night or dark places.
4.2 Fluorescents
The spike at about 400nm and 440nm with fluorescent bulbs is from the mercury in the bulb.
4.2.1 Philips 80W, 4000K, 82 CRI
4.2.2 Philips 55W, 5000K, 90 CRI
4.3 LEDs
4.3.1 Philips 3.5W, 4000K, 80 CRI, 310 Lumen
4.3.2 Philips 4W, 4000K, 90 CRI, 314 Lumen
4.4 Ceramic Metal Halide
4.4.1 Philips 150W, 4100K, 96 CRI, 12,000 Lumens
The Ceramic Metal Halide bulb used in this project.
4.5 Incandescent Light Bulb (Full Spectrum)
Below is the spectral distribution of a halogen bulb which has a color temperature of 2700K-3000K. You can see how there is more power output in the red part of the spectrum giving it more of a “warm” color temperature than sunlight.
5. Bulb Choices & Ballast Choices
There are two main types of metal halide bulbs – quartz and ceramic. Ceramic bulbs in general, have better color rendering, color stability, and efficacy (higher burning temperatures), so they are the logical choice.
Metal Halide Bulb Choices
A list of a few metal hailde bulbs that would be good candidates for a light therapy light.| Brand | Bulb | Part # | Open Rated | Source | Watts | Market | Bulb | Base | CRI min/nom | Color Tempature | Initial Lumens | Mean Lumens | Life (hours) | Lm/W | Volt | Current EM/EL | Datasheet | Product Family Datasheet | Product Family Page |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GE | CMH150TU/830/G12 | 20017 | T6/T19 | G12 | 82 | 3000K | 14000 | 11000 | 12000 | 93 | |||||||||
| GE | CMH150TU/942/G12 | 20018 | T6/T19 | G12 | 94 | 4200K | 13000 | 11000 | 12000 | 87 | |||||||||
| GE | CMH150TD830RX7S | 92589 | T7/T25 | Rx7s | 80 | 3000K | 14000 | 11500 | 15000 | 93 | |||||||||
| GE | CMH150TD942RX7S | 92590 | T7/T25 | Rx7s | 93 | 4200K | 14000 | 11500 | 15000 | 93 | |||||||||
| Philips | MasterColor CDM-T 150W/830 T6 1CT | 928083705115 | No | 1 | 150 | America | T6/T19 | G12 | 88 | 3000K | 13600 | 9600 | 12000 | 95 | 96 | 1.8 / 1.62 | Family Datasheet | Family Page | |
| Philips | MASTERColour CDM-T 150W/830 G12 1CT | 928083705176 | No | 150 | EU | T6/T19 | G12 | 88 | 3000K | 13600 | 9600 | 12000 | 91 | 96 | 1.8 / 1.62 | Family Page | |||
| Philips | CDM-SA/T 150W/942 1CT | 928086605103 | No | 1 | 150 | EU | T6/T19 | G12 | 95 | 3900K | 14000 | 9000 | 91 | 1.8 | |||||
| Philips | MASTERColour CDM-T 150W/942 G12 1CT | 928084605175 | No | 150 | EU | T6/T19 | G12 | 96 | 4200K | 12700 | 12000 | 88 | 90 | 1.9 / 1.7 | Family Page | ||||
| Philips | MASTERColour CDM-TD 150W/830 RX7s 1CT | 928083605177 | No | 1, 2 | 150 | EU | T7/T25 | RX7s | 88 | 3000K | 13250 | 16000 | 91 | 98 | 1.8 | Family Page | |||
| Philips | MASTERColour CDM-TD 150W/942 RX7s 1CT | 928084805177 | No | 1 | 150 | EU | T7/T25 | RX7s | 96 | 4200K | 13750 | 16000 | 87 | 103 | 1.8 | Family Page | |||
| Philips | MASTERColour CDM-TP 150W/942 PGX12-2 1CT | 928086209230 | Yes | 150 | EU | T31 | PGX12-2 | 95 | 4200K | 12000 | 81 | 96 | 1.8 | Family Page | |||||
| Philips | MasterColor CDM 150W/830 Med ED17P CL ALTO+FB | 928601132301 | 150 | ED17P | E26 | 85 | 3000K | 12900 | 9545 | 16000 | 86 | 95 | 1.8 | Datasheet | Family Datasheet | Family Page | |||
| Philips | MasterColor CDM 150W/940 Med ED17P CL ALTO+FB | 928601132701 | 150 | ED17P | E26 | 92 | 4000K | 12000 | 9000 | 20000 | 80 | 95 | 1.8 | ||||||
| Philips | MasterColor CDM 150W/830 Med ED17 CL ALTO | 928601132101 | 150 | ED17 | E26 | 85 | 3000K | 14000 | 10500 | 16000 | 95 | 95 | Family Datasheet | Family Page | |||||
| Philips | MasterColor CDM 150W/940 Med ED17 CL ALTO | 928601132701 | 150 | ED17 | E26 | 92 | 4000K | 13000 | 9000 | 20000 | 88 | 95 | |||||||
| Philips | MasterColor CDM-T Elite 210W/930 T9 1CT | 928601164702 | No | 210 | America | T-9 | PGZ18 | 87/90 | 2950K | 24150 | 27000 | 115 | 100 | /2.1 | |||||
| Philips | MasterColor CDM-T Elite 210W/942 T9 U | 928601164902 | No | 210 | America | T-9 | PGZ18 | 85/92 | 4120K | 23000 | 30000 | 108 | 98 | /2.1 | |||||
| Philips | MasterColor CDM-T Elite 210W/930 T12 U P 1CT | 928601167002 | Yes | 210 | America | T12 | PGZX18 | 85/90 | 2950K | 23300 | 20000 | 111 | 100 | /2.1 | Family Datasheet | Family Page | |||
| Philips | MasterColor CDM-T Elite 210W/942 T12 P 1CT | 928601167202 | Yes | 210 | America | T12 | PGZX18 | 85/92 | 4040K | 22800 | 20000 | 108 | 105 | /2.1 | |||||
| Philips | MasterColor CDM-T Elite 315W/930 T9 1CT | 928601164602 | No | 315 | America | T-9 | PGZ18 | 85/90 | 3100K | 38700 | 30000 | 120 | 100 | /3.15 | |||||
| Philips | MasterColor CDM-T Elite 315W/942 T9 U | 928601164802 | No | 315 | America | T-9 | PGZ18 | 85/93 | 4200K | 35500 | 30000 | 113 | 100 | /3.15 | |||||
| Philips | MasterColor CDM-T Elite 315W/930 T12 U P 1CT | 928601167102 | Yes | 315 | America | T12 | PGZX18 | 85/90 | 3100K | 36200 | 20000 | 115 | 100 | /3.15 | |||||
| Philips | MasterColor CDM-T Elite 315W/942 T12 U P 1CT | 928601167302 | Yes | 1 | 315 | America | T12 | PGZX18 | 85/90 | 4200K | 34300 | 20000 | 109 | 100 | /3.15 | ||||
| Philips | Mastercolor CDM-T Elite 315W T12 CL Agro | 415216 | 315 | T12 | PGZX18 | 92 | 3100K | 33000 | 20000 | 105 | 98 | / 3.15 | Family Datasheet | Family Page | |||||
| OSRAM | HCI-T 150 W/830 WDL G12 | 150 | G12 | 88 | 3000K | 15100 | 15000 | 103 | 1.8 | Datasheet | Family Datasheet | Family Page | |||||||
| OSRAM | HCI-T 150 W/942 NDL PB G12 | 150 | G12 | 96 | 4200K | 14700 | 15000 | 100 | 1.8 | Datasheet | |||||||||
| OSRAM | HCI-TS 150 W/830 WDL RX7S-24 | 150 | RX7s | 90 | 3000K | 15000 | 15000 | 1.8 | Datasheet | ||||||||||
| OSRAM | HCI-TS 150 W/942 NDL PB RX7S-24 | 150 | RX7s | 95 | 4200K | 14800 | 15000 | 101 | 1.8 | Datasheet | |||||||||
| OSRAM | HCI-E/P 150 W/830 WDL PB CO E27 | 150 | E27 | 90 | 2990K | 13700 | 12000 | 102 | 98 | Datasheet | Family Datasheet | Family Page | |||||||
| OSRAM | HCI-TM 250 W/930 WDL G22 | 250 | G22 | Family Page | |||||||||||||||
| OSRAM | HCI-TM 250 W/942 NDL PB G22 | 250 | G22 | 96 | 4120K | 25300 | 100 | 3 | |||||||||||
| Sylvania | MC150T7.5/U/G12/830 | 64359 | 150 | 89 | 3000K | 15500 | 12400 | 15000 | |||||||||||
| Sylvania | MC150T7.5/U/G12/940PB | 64337 | 150 | 95 | 4200K | 14500 | 11600 | 15000 |
I put a few higher wattage (above 150 watt) bulbs in the table above but it is tricky to go above 150 watts with ceramic metal halide. The ballast options get limited and the few electronic ballasts available for these high wattage lamps generally require 240v or 480V supply voltage. Magnetic ballasts work on some high wattage ceramic metal halide bulbs but are loud, inefficient, and reduce bulb life, however, the biggest reason I am not use them is the 60Hz transformer noise/buzz.
Other bulbs that could make good lights:
Philips 250w Ceramic ST 90 CRI, 23000 lm, 3200K
Philips MSR Hot Restrike 125W – 18,000W, 6000K
| Brand | Part Number | Notes | Source | Watt | Input Volts | Bulb # | Power Factor | Operating frequency | ANSI ballast code | Length | Width | Height | Weight | Other features | Datasheet |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GE | 87576 GEMH150-SLJ-MV | 150 | 120-277 | 1 | 130 | M102, C142, M142 | 7.3" | 2.6" | 2.2" | Datasheet | |||||
| Philips | IMH-150-H-LF IMH-150-H-BLS | 150 | 120-277 | 1 | 0.9 | C102/M102 C142/M142 | 5.7" | 3.6" | 1.5" | Datasheet | |||||
| Philips | IZTMH-150-C-LF | 150 | 120-277 | 1 | 0.9 | C102/M102 C142/M142 | 7.2" | 3.6" | 1.5" | Dimmable | Datasheet | ||||
| Philips | IMH-175-C-LF IMH-175-C-BLS | loud | 150-175 | 200-277 | 1 | 0.9 | C102/M102 C142/M142 M137, M152 | 7.2" | 3.6" | 1.5" | Datasheet | ||||
| Philips | IZTMH-210315-R-LF | 210-315 | 208-277 | 1 | 0.9 | C182, C183 | 7.5" | 4.9" | 2.2" | 4.5 lbs | |||||
| Philips | IMH-210-T-LF IMH-210-T-LS | 210 | 208-277 | 1 | 0.97 | C183 | 6.5" | 3.9" | 2.4" | 3.1 lbs | |||||
| Hatch Lighting | MC150-1-F-120U MC150-1-J-120U | F - With feet J - Bottom feed with studs | 1 | 150 | 108 - 132V | 1 | Datasheet | ||||||||
| Hatch Lighting | MC150-1-F-277U MC150-1-J-277U | Full Size | 150 | 220 - 277V | 1 | Datasheet | |||||||||
| China Eletronics (CES / Orido) | NL-H150/UBN1A NL-H150/UBN1B | Side / Bottom wire | 150 | 120-277 | 1 | Datasheet | |||||||||
| China Eletronics (CES / Orido) | NL-H150/230BN4A | 150 | 230 | 1 | Datasheet | ||||||||||
| Universal Lighting Technologies | M15012-27CK-5EU-F M15012-27CK-5EU-J | 150 | M/C102/E M/C142/E | 5.51" (140mm) | 3.62" (92mm) | 1.57" (40mm) | |||||||||
| Universal Lighting Technologies | M15012/27CK-5EU-JT3 | 150 | M/C102 M/C142 |
6. The Build
I ended up building two lights, a omni-directional light and a directional light as I had a lot of fun with this project.
6.1 DIY Omni-Directional Full Spectrum Sunlight Simulator Lamp Build
Since the bulb I chose is not rated for open enclosures and I did not want anyone touching it I looked around online for something to put it in. I decided to use a hurricane candle holder. I didn’t like many, but I settled on the Crate & Barrel “Mica Hurricane candle holder” which I picked up on sale locally for $15 and is no longer sold. They do now sell metal halide bulbs rated for open enclosures some of which are listed in the bulb choices table.
6.1.1 Parts for DIY Omni-Directional Light Fixture
- Crate & Barrel “Mica Hurricane candle holder”, no longer sold
- Philips MASTERColour CDM-T 150W/942 G12 1CT bulb
- G12 base lamp holder with leads,
from Ebay
- 5kV+ rated test lead wire – Pomona 6733-0 10kV, Pomona 6734-0 5kV
- 5kV+ rated banana plugs – Pomona 5169-2
- Tubular Tinned Copper Braid, 1/8″ Diameter, 25′ (not required)
6.1.2 Parts for Ballast Enclosure
- 203mm x 144mm x 68mm external (8″ x 5.7″ x 2.7″) aluminium enclosure from Ebay
- Ballast, I used Universal Lighting Technologies M15012-27CK-5EU-J
- LCR 081M low leakage EMI filtered IEC320C13 power entry module (overkill, any IEC320C13 chassis mount power plug will work)
- 19mm 12V white LED ring push button switch from Ebay
- LCD Hour Meter from Ebay, used to track bulb life (optional)
- Silicone Tubing as extra insulator (optional)
- Thermal Compound Paste Grease to thermally bridge ballast to enclosure
- 12VDC power supply for hour meter counter and lighted switch (optional)
6.1.3 Ballast Enclosure Build
6.1.3 Sunlight Simulator Light Therapy Lamp Fixture
6.2 DIY Directional Full Spectrum Lamp Build
6.2.1 Parts for DIY Directional Light Fixture
- JC2212 Aluminum Enclosure from Ebay
Internal dimensions: 203.5mm W x 112mm H x 300mm D
External dimensions: 220mm W x 120mm H x 311mm D - RX7s lamp holder fixture from Ebay
- Philips MASTERColour CDM-TD 150W/942 RX7s 1CT bulb
- Ballast, I used Universal Lighting Technologies M15012-27CK-5EU-J
- LCR 081M low leakage EMI filtered IEC320C13 power entry module from Ebay (overkill, any IEC320C13 chassis mount power plug will work)
- 19mm 12V white LED ring push button switch from Ebay
- LCD Hour Meter from Ebay, used to track bulb life (optional)
- 12VDC power supply for hour meter counter and lighted switch (optional)
6.2.2 Directional Light Build
7. Conclusion, Lessons Learned, Future Improvements
1) It’s hard to go too bright. One 12,000 lumens 150 watt metal halide lamp will work if you have it close by you or in a small room but I really recommend going brighter with multiple 150 watt lights or a higher wattage bulb and ballast, I think the sweet spot is 24,000-50,000 lumens.
2) I prefer the directional full spectrum light over the omni-directional lamp. It allows you to put it on top of a piece of furniture such as a bookcase and bounce all the light off the ceiling and it has a higher lux rating as the light is focused. The omni-directional light tends to create too much glare if you are trying to work on the computer and use the light at the same time.
3) Don’t use magnetic ballast, they are loud. The 60hz hum is really annoying to me.
4) Bouncing light off the ceiling is definitely the most pleasant way to produce a low glare work environment for computers work and task lighting. It would be interesting to try and build a light bright enough to bounce off the ceiling and still meet the studied therapeutic levels of light output needed for light therapy, to do this you will have to go brighter. The 150w directional lamp bounced off the ceiling definitely produces a pleasant bright warmth to the room. I did consider building a light with a 315 watt, 35,000 lumen ceramic metal halide bulb but the philips electronic ballast to drive this lamp is in excess of $300 and the bulb is about $85, there may be other sources of ballast to drive these bulbs.
Disclosure: Some of the links to products and supplies on this page go through my Amazon Associates and/or Ebay partner account in hopes of helping to pay for web hosting and maybe even allow me to start a new project. If you are going to purchase any of the supplies listed here and if you found my site’s content useful, please consider purchasing through my links it will not cost you any more, thanks!
Great project. Any chance of getting a wiring diagram for 6.2? Thanks.
Hi Robert, I will try to draw up something in the next few days.
Great article, do you know any other source for the directional fixture other than ebay? I have been searching and not having a lot of luck. I don’t (won’t) use ebay.
Hi Zach, you may be able to find some on the foreign trade sites like alibaba. Make sure it is rated for metal halide which needs conductors that can handle the 5kV starting voltage. Rx7s are metal halide fixtures while R7S are halogen bulb fixtures.
Hi, Luke, this is cool!
I built a 30,000 lumen LED light recently, and wrote a similar blog post about it: http://meaningness.com/metablog/sad-light-lumens
We came to many of the same conclusions—among them that the commercial products are radically inadequate!
The last section of my post is about the possibility of using metal halide bulbs—where you mentioned the possibility of using LEDs!
I first experimented with LEDs two years ago, but the parts available then were not adequate without more engineering than I wanted to do. But now I think they may have the edge (and presumably will continue to improve).
LEDs are rapidly becoming a contender but the biggest issue still is the high output LEDs are extremely expensive for high CRI and most of the ones I am finding are lower color temperatures. I have not found many sources of a reputable, high quality, high lumen LED that has a high colors temperatures (cool) and high CRI. I still think for the next few years a 315w-400w ceramic metal halide is the best bet, LEDs are quickly catching up.
I have been eyeing the Luminus XNova studio series LED, they may just be the ticket: 12,000 lumens, 5600K, 95 CRI. Part number: CVM-27-56-95-36-AA00-F2-2 – $73 each from digikey and probably would be best to go with three. Then you need heatsinks and power supplies (I mention a power supply that will work below)
http://www.luminus.com/products/Luminus_Xnova_Studio_Datasheet.pdf
Here is also a snippet from my reply to a comment on Hack A Day about Bridgelux LEDs…
Great projects Luke. You really have done a nice job. Have you looked into the safety of using a Metal Halide bulb without a UV filter? Metal Halides emit lots of blue, which is cancer causing. I’m sure you know this but worry about eye and skin safety. Most commercial light boxes have UV filters. I think the problem with metal halide bulbs as SAD lamps is the UV exposure. Have you noticed your skin dries out or your eyes itch after use? I hope I am wrong on the UV exposure, and don’t want to rain on your parade. I just know UV exposure is bad stuff. Let me know your thoughts. Thanks!
Hi Jim,
The bulbs I am using are made from UV blocking glass and have UV filter coatings build into the bulb to address that. They do not output any dangerous UVC or UVB. Fluorescents on the other hand generate UVC and have a phosphor coating on the glass that convert the UVC generated by the florescent bulb to visible light but some UVC does leak out and I have seem the phosphor coating breakdown with time on some CFLs. With ceramic metal halide bulbs most of the light emitted is in the visible spectrum to begin with but you do get the spikes in the UV spectrum from the mercury in the bulb which can be mostly blocked with the bulbs glass and coatings. The ceramic metal halide bulbs I am using do output a small amount of longwave UVA close to visible light (350-400nm) but far less than you get from sun exposure and not dangerous.
Hi. Great project and write up. I want to build something similar, but unfortunately I have a tight budget. I’m wonder if you could help me with some questions I have. Do you think this used ballast will work? http://www.ebay.com/itm/PHILIPS-150W-HID-PV-150-S-MH-CDM-T-for-HQI-Metal-Halide-Ballast-/222000846274?hash=item33b04815c2:g:VbgAAOSwo0JWKTl6
Also the all the G12 holders I can find on eBay says 1000V but the lamp and ballast is 5kV, right? Last, is it possible to just hard wire the switch and turn it on and off with the outlet plug?
Thanks
Hi Jens,
I can’t find any information on this exact ballast part number but is appears to be the correct ballast to drive a 150w CMH bulb, it is 220-240V rated so it will not work on standard 120V US branch circuits.
The voltage rating is confusing but the sockets rated for 1kV should be fine as that is the max operating voltage rating not starting (ignition) voltage. If you look in the datasheet of the OSRAM G12 lamp holder I used it lists the max lamp voltage of 1kV but max ignition voltage of 5kV http://www.osram.com/appsinfo/pdc/pdf.do?cid=GPS01_1028324&mpid=ZMP_1007498&vid=PP_EUROPE_Europe_eCat&lid=EN
You can plug the ballast directly into the wall without a switch.
I’m in the EU so that’s ok. Thanks a lot.
I just skimmed this article so I could of missed it. According to all medical literature on the subject of light therapy the light source has to be placed above eye level since the receptors activated by light therapy are only at the bottom of the retina. You don’t have to get super technical with it just roughly a 45 degree angle down from center of pupil. I’m sure you’re correct about the bulb manufacturers lux reading. The scholarly medical journals do take the reading in front of the pupil which is where the 10000-12000 lux requirement comes from. Ideally you should be able to get that reading from three feet no less than a foot or it would just be obtrusive for daily tasks. Also beware degenerative retinal diseases will progress more rapidly around light boxes and can also trigger manic episodes if a person is bipolar.
Awesome job Luke!
I’m considering building SAD LED glasses that I can wear while preparing my smoothie before work. I’ve been looking at commercial ones but they cost hundreds and don’t look like they would last long enough for the price. I’m thinking 2500 lux (at 5cm from eye), preferably blue-green, uv-free LEDS.
At 43 seconds into this video: https://www.youtube.com/watch?v=c9XTY-jWBcw a rudimentary pair is shown. I wear prescription glasses so I thought I could modify an old pair to wear in the mornings.
I have no idea about the circuitry required or where to source the components. Any help here is greatly appreciated!
I have not done any research on this but you can buy extremely high CRI LEDs (96+) in the much lower output needed for direct exposure using them mounted to glasses and they are not too expensive for the low output needed. I am of the approach of trying to replicate the sun spectrum as it’s what keeps SAD people from experiencing symptoms in the summer instead of just using blue and green light.
When using LED, CRI could be meaningless, has it check light output at some specific color (frequency), and it is possible for a manufacturer to choose LED and coating to target those frenquency. What you need is the Spectral Power Distribution, LED output a lot of blue light and the coating emit toward yellow making it look white.
Have you ever looked into Philips Graphica? They have almost no spiking and I’m thinking that compared to metal halide, at least their color temperatures (either 5500K or 6500K) would make for a better sun light replacement?
They are less efficient though…
Is it possible to wire the light for the Omni-directional lamp, straight into an outlet plug? I want to build one with just a switch plug on it, if possible.
Hello. Was looking osram cera which is 4200lm with e27 socket, which means no ballast. Was wondering if 4x4200lm is the same as 1x16800lm.
As far as LEDs, I listed to Dr.Mercola and he warns against using these.
How LED Lighting May Compromise Your Health
https://articles.mercola.com/sites/articles/archive/2016/10/23/near-infrared-led-lighting.aspx
Hi ! Great project. It’s now 2018 and still, high CRI LED lamps cost 40$ and 1500lumen bulbs have CRI = 80, which is poor.
I am decided to build my own version of this lamp. However, in the picture, the lamp does not look like it is outputting the 12700 lumens(10,000lux). Is the lamp actually that much bright, and it’s just an effect of the camera light adjustment?.
For reference, a 100W replacement led (~14W ) is 1500 lumens.
Also, have you had any issue so far (2015 – 2018 ) or update to the lamp?
Thanks in advance!
I decided to do something very simple,
I just bought 2 UBERHAUS 500W halogen working lamp at 19.19$CAD each from Rona, the kind of light use in construction site, no construction needed, just plug them in.
I just check with my light meter and they produce 10,000 Lux at 24 inches, but they produce a lot of heat too of course, but I just feel like I am down south under the sun
at 500 watts that is a lot of electricity, how long do you have them plugged in? when do you use them in the morning just when you wake up?
Yes it is a lot of electricity and I am using 2 of them. But here in québec, electricity is very cheap so after one hour of use, I would have used 1000W; but at 7 cents a kilowatt, it only cost 7 cents!.
I do not have musch time in the morning, so I use for only 15 or 20 minutes, but in the evening , I may use it for an hour
How are they working for you?
Yes, it work very fine, normally when november comes around, i feel so bad that I have the impression that I will not see spring (I am not kidding about that).
So a bit of exposure in the morning before going to work and a bit more in the evening (a have more time) is perfect for me
I cannot find this lightbulb on amazon. Can you suggest a similar product that is available on amazon?
I am in the US.
Hey, I’m using your guide for a cool budget build! Very excited about it. I’m doing 3x 70 watt lamps under 100$ total.
I have a couple questions for you. I’m using NAiS m7012-27CK ballasts, and they are marked as “thermally protected” which as I understand simply means they will shut off if they overheat. My question is, how much cooling do ballasts needs? I’ve worked on computer cooling systems, so I can tell your builds with big hunks of aluminum casing should be cooling them down quite a bit. Do you think it’s necessary to have a large aluminum or copper sink like that? It occurred to me I could treat the wattage as a CPU TDP and get a desktop heatsink for it rated at 70 watts.
Thanks for this guide and sending me off on a new project.
Hello I would like to know an information and what do you think of that? I did some research and found that CMH bulbs emit UV light. However does the type of UV light emitted by these bulbs are dangerous for the eyes? I also want to know if I can use them continuously for permanent lighting?
info taken from:
https://www.epicgardening.com/cmh-grow-lights/
MH grow lights provide UV (ultra violet) radiation, which although being outside of our range of vision is beneficial (at certain ranges and intensities) to plant growth and development. They produce UV-A, UV-B and UV-C Light, but UV-C is generally very harmful to human eyes. So most high quality manufacturers use a glass filter to block the UV-C output while leaving UV-A and UV-B output intact.
Hey Luke,
Thanks for this piece.
I am looking to build a sunlight simulator at work that will fill uniformaly a 3.5 by 3.5 meter room.
What would be my best bet for light fixtures, and possible placement?
Appreciate your answer in advance.
Hello Author researcher fabricator,
I was extremely lucky to find this site while looking to improve our lighting for the second time in 5 years.
My wife has macular degeneration & I must improve our lighting & one step was to make a start with solar simulation since we are elderly & locked down for more than a year.
You have pointed my search in a direction since what I learned from your site has very much enlightened me.
I hope this site is still monitored and that I can seek further enlightenment if you are able to let me know if your R & D is still ongoing.
I look forward to hear from you.
Vincent Gonelli
Hi Luke, Your webpage and project inspired me to build my own SAD light. For higher wattage, I found a place that sells deeply discounted electronic ballasts. I am using a 600W Eye Hortilux Blue with a CRI of 95 and color temp of 5000K and also Eye Hortilux 400W Blue with a CRI of 90 and color temp of 6500K. These are mounted in the same fixture, an arch floor lamp with a 15″ shade. It puts out a beautiful light that I believe is very close to natural sunlight. Being horticultural metal halides, it also emits a fair amount of UV which is great for vitamin D production, which plays a large part in SAD. That being said about UV, caution most be exercised in exposure time and NEVER staring into the light source.