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149CommentsBoston, MA USAJoined May 10th, 2006
Light seems to be a dominant theme in my interests.

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  • starphire commented on sjowett's instructable Mega Torch - the ultimate guide1 month ago
    Mega Torch - the ultimate guide

    This appears to be a well-thought-out design; you are right to take cooling seriously, as there are far too many DIY types claiming their LED torches are adequately cooled with obviously undersized heatsinks (or no fans) simply because "it's only warm to the touch" or "it's been working fine for a dozen hours already". Then others use their design as a guide and thus perpetuate the fallacy.I am wondering what "Tier 1" manufacturer you've been able to find with $80 LED modules. Can you provide a link to one? By my definition of the term, there is no such company manufacturing any 100W LED arrays in this package style. This applies to the smaller 10W and 20W arrays in similar square packages, as well. The "good" modules of this type go to large sca...see more »This appears to be a well-thought-out design; you are right to take cooling seriously, as there are far too many DIY types claiming their LED torches are adequately cooled with obviously undersized heatsinks (or no fans) simply because "it's only warm to the touch" or "it's been working fine for a dozen hours already". Then others use their design as a guide and thus perpetuate the fallacy.I am wondering what "Tier 1" manufacturer you've been able to find with $80 LED modules. Can you provide a link to one? By my definition of the term, there is no such company manufacturing any 100W LED arrays in this package style. This applies to the smaller 10W and 20W arrays in similar square packages, as well. The "good" modules of this type go to large scale lighting OEMs, mostly for commercial lighting applications. The substandard ones go into low quality light fixtures, or sold as modules on aliexpress, ebay, amazon and so forth.The most prevalent defect in these no-brand square LED modules is actually not detectable with low-current testing looking for unusually dim or bright LEDs. It is that the whole module does not emit nearly the amount of light they were specified to produce. A failed luminosity test sends them to the same scrap bin as the "defective" modules you tested for. It's an excellent business for these online resellers since neither they nor their customers will have the necessary testing equipment to determine that a "100,000" lumen module actually only puts out half that much light at full rated power. The 3 out of 4 "good" modules you got are very likely not as bright as claimed, so that would be the reason they were also sold at low prices through aliexpress. In other words, it's not as much of a lottery as it might seem since for most of us it still seems ridiculously bright to our eyes.

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  • How to build an insanely bright LED flashlight!

    The internal LEDs are the cheapest form of low-power LEDs, each rated for 0.1 Watt or so and wholesaling for a few cents each. They are wired in two banks of 6, to be compatible with the original high/low beam wiring. Maximum total power of the bulb is 1.2 Watts, yielding 120 lumens. Or 100 lumens/Watt, which is low performance (nowadays) for something meant as a vehicle headlight. Might be OK for off road use, but it won't be as focused as the halogen bulb it was meant to replace.

    OK, that hack would double the light output of the floating lantern, but at 120 lumens it's still only a tiny fraction of the light that can be obtained from the project in this instructable. So either you're suggesting that nobody really needs that much portable light, or making some other point that's eluding me.But did you notice that the eveready lantern runs on either 2 or 4 D cells?That's because it's wired to run on only 3 Volts, not 6. Adding a second pair of D cells in parallel simply doubles the runtime, but it's still a large 3 Volt flashlight. So first you'll need to modify the battery holder so the 4 batteries are wired in series, which might or might not be trivial depending on how it's put together.Another issue with your suggestion is that the original lantern reflector ...see more »OK, that hack would double the light output of the floating lantern, but at 120 lumens it's still only a tiny fraction of the light that can be obtained from the project in this instructable. So either you're suggesting that nobody really needs that much portable light, or making some other point that's eluding me.But did you notice that the eveready lantern runs on either 2 or 4 D cells?That's because it's wired to run on only 3 Volts, not 6. Adding a second pair of D cells in parallel simply doubles the runtime, but it's still a large 3 Volt flashlight. So first you'll need to modify the battery holder so the 4 batteries are wired in series, which might or might not be trivial depending on how it's put together.Another issue with your suggestion is that the original lantern reflector was designed for the single LED with one very small (single point) light source. Replacing that with a retrofit bulb with cluster LEDs means fussing to get it centered (how? I can't even imagine) at the reflector's focal point, and a MUCH less focused beam coming out of the lantern, no matter how you slice it. Count on turning it into a floodlight, not a spotlight, with this approach.All that effort for something that a $15 LED headlight or flashlight from the store will easily equal or exceed. 120 lumens is no big deal these days.

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  • starphire commented on JuanF92's instructable NeoBulb (Neopixel bulb with sensor)1 month ago
    NeoBulb (Neopixel bulb with sensor)

    What sort of custom enclosure could then easily be screwed into a regular light socket, and at what cost? I can buy a cheap LED bulb for less than $3 at discount stores nowadays. I doubt I could find an empty bulb housing (or any kind of nice enclosure for electronics, for that matter) for that price online, with the cost of shipping.The point of screw-in replacement LED bulbs is to take advantage of hundreds of millions of existing light fixtures. There is nothing wrong (and even some good advantages) to mounting LED lights in other sorts of enclosures for custom room lighting, but the legacy of the Edison type light bulb is so deeply embedded in the world it does make sense to adapt new technology (such as smart bulbs) to work with it.

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  • starphire commented on rdrew5's instructable LED RGB Light Painting Light Spinner1 month ago
    LED RGB Light Painting Light Spinner

    Nice results! It does leave a lot of details to the imagination when it comes to selecting, controlling and powering the LEDs. There are many kinds of LED strips on the market, such that even someone who knows some electronics and has used them before could be confused about what they need to get similar results for light painting effects.Your estimate of LED lifetime at different voltages is somewhat misleading, though. It's a very nonlinear system, since these 12V strips rely on simple resistors to limit the current to the LEDs based on an assumed 12VDC source. Having this many LEDs powered by two 9V batteries, what is actually saving them from swift destruction at 18V is the 9V battery's own internal resistance (which limits the current they can supply, even if you add a few AAs in s...see more »Nice results! It does leave a lot of details to the imagination when it comes to selecting, controlling and powering the LEDs. There are many kinds of LED strips on the market, such that even someone who knows some electronics and has used them before could be confused about what they need to get similar results for light painting effects.Your estimate of LED lifetime at different voltages is somewhat misleading, though. It's a very nonlinear system, since these 12V strips rely on simple resistors to limit the current to the LEDs based on an assumed 12VDC source. Having this many LEDs powered by two 9V batteries, what is actually saving them from swift destruction at 18V is the 9V battery's own internal resistance (which limits the current they can supply, even if you add a few AAs in series with them). An 18V power pack made entirely out of AA batteries, or lithium, or any power source that can supply more than a few hundred milliamps continuously will more likely yield an extremely short and disappointing lifetime, nowhere near 10,000 hours!

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  • starphire commented on Jules1050's instructable PlexiClock2 months ago
    PlexiClock

    Sure, *you* could do that with EL wire or tape, if you wanted to. However, I was responding to rafununu's comment about Neopixels, which are definitely programmable LEDs and not EL light sources at all (and also come in different forms, not just strips). I don't see how your point connects to theirs at all, unless you are able to read minds!After about 20 years of experience with EL wire, though, I would note that using EL tape as clock segments would have some disadvantages: each segment will require a high voltage driver or switch to control it; it will be dimmer than LED; it will be limited to a single color (unlike an RGB pixel like Neopixels); it will be expensive compared to LEDs, and it will get dimmer and dimmer over time (lifetime rated for a few thousand hours). Also, cutting ...see more »Sure, *you* could do that with EL wire or tape, if you wanted to. However, I was responding to rafununu's comment about Neopixels, which are definitely programmable LEDs and not EL light sources at all (and also come in different forms, not just strips). I don't see how your point connects to theirs at all, unless you are able to read minds!After about 20 years of experience with EL wire, though, I would note that using EL tape as clock segments would have some disadvantages: each segment will require a high voltage driver or switch to control it; it will be dimmer than LED; it will be limited to a single color (unlike an RGB pixel like Neopixels); it will be expensive compared to LEDs, and it will get dimmer and dimmer over time (lifetime rated for a few thousand hours). Also, cutting and attaching wires to EL tape pieces is not easy! Maybe not the best choice for a clock display that is always on, but yes you could make a clock that way.I encourage you to make your own wall-size clock using EL tape and post your instructable here. It will be a different project. And it won't be able to change color, which seemed to be rafununu's point. Happy building!

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  • starphire commented on Jules1050's instructable PlexiClock2 months ago
    PlexiClock

    Yes, just remember that some LED package types are much better suited to edge lighting acrylic than other types. The 5mm LEDs with a built in lens, such as the kind used in this Instructable are MUCH better for this purpose than any of the flat surface mounted LED packages which do not have lenses. Because only the light near the central axis will be efficiently conducted through the acrylic to illuminate the etched areas - light emitted outside that cone of acceptance will be completely lost.

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  • POV Globe 24bit true color and simple HW

    noch100, I am guessing that you're not familiar with LED POV globes as a concept? Various versions of this idea have been made for at least 15 years now (that I know of). There have even been mass-produced versions sold for POS advertising and as a decorative gadget.A brief look shows me that the control electronics and LEDs used in this version are *quite* different than the one you referenced. This one is honestly simpler in a number of ways for many people to build for themselves, in my opinion.I've seen earlier plans published here and on sites like Hack-A-Day, if your question is regarding originality of the concept as a DIY project.Also, I am wondering why link that instructable through an unnecessary and annoying ad-based service? instead of simply linking to the instructable its...see more »noch100, I am guessing that you're not familiar with LED POV globes as a concept? Various versions of this idea have been made for at least 15 years now (that I know of). There have even been mass-produced versions sold for POS advertising and as a decorative gadget.A brief look shows me that the control electronics and LEDs used in this version are *quite* different than the one you referenced. This one is honestly simpler in a number of ways for many people to build for themselves, in my opinion.I've seen earlier plans published here and on sites like Hack-A-Day, if your question is regarding originality of the concept as a DIY project.Also, I am wondering why link that instructable through an unnecessary and annoying ad-based service? instead of simply linking to the instructable itself?Gelstronic, nice work on this design.

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  • Hack an Expensive LED Bulb to Fit (nearly) Anywhere!

    The original cast aluminum housing of the LED bulb might not be super efficient at moving heat away from the LED module, but assuredly the designers did the best they could given cost and size limits, and then tested it thoroughly to make sure it would last a reasonably long life under expected conditions.If modifying the heatsink and heatflow arrangements from what it was designed for, some critical factors are: airflow (does the glass cover allow any airflow or is this now a "sealed" fixture?), type of metal used as heatsink (steel is *much* poorer at conducting heat than aluminum is), and thickness of the metal where it meets other heatsink parts. If the aluminum gussets on the original aluminum housing were designed to be "heat flow highways", then a thin sheet o...see more »The original cast aluminum housing of the LED bulb might not be super efficient at moving heat away from the LED module, but assuredly the designers did the best they could given cost and size limits, and then tested it thoroughly to make sure it would last a reasonably long life under expected conditions.If modifying the heatsink and heatflow arrangements from what it was designed for, some critical factors are: airflow (does the glass cover allow any airflow or is this now a "sealed" fixture?), type of metal used as heatsink (steel is *much* poorer at conducting heat than aluminum is), and thickness of the metal where it meets other heatsink parts. If the aluminum gussets on the original aluminum housing were designed to be "heat flow highways", then a thin sheet of steel is a narrow alley in comparison. To extend the analogy, If the LED module is a city center in summer, think of a traffic jam of hot cars all trying to go over a few narrow bridges to get to the cooler countryside!Excuse the funny analogy, my point is that the LED module *does* need to have a heatsink arrangement that's at least as efficient as the original bulb offers, just as the author noted. But this particular arrangement for heatsinking the LED module is very likely to be somewhat worse for the LEDs. It may not fail right away, but statistically its lifetime will be reduced by 50% for every 10 degree Celsius increase in the chip temperatures.I want to be constructive and helpful, so I will suggest this: at least make a thick circle of aluminum plate as large as the punched steel piece from the fan. It will work better at moving heat than the thin steel piece alone. If air can still flow upwards through the bulb cavity on this fan, that is also a major help. For those interested in learning more about heat sink design, there are resources online. A good keyword to start with is "thermal resistance", as heat flow can be predicted using equations similar to Ohms law for electrical resistance.

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  • starphire commented on akolk1's instructable Huge addressable RGB LED (ceiling) panel5 months ago
    Huge addressable RGB LED (ceiling) panel

    Regarding power requirements, there is a hidden power leech in the 12V WS2811 pixels and strips- each controller IC still needs 5V, which is supplied by a zener diode and a resistor. Most of the idling power draw (no LEDs lit) goes into feeding all of those little zener voltage regulators, which really adds up for hundreds of pixels! The 5V versions (WS281201/12) don't have this issue..So for a little more money one could instead wire 3x as many 5V strips in the same area and get the same light output with more resolution and noticeably lower average power consumption. i.e. higher efficiencyA rule of thumb for RGB light arrays is that actual power draw will typically be about 1/2-1/3 of theoretical maximum unless the effects are heavy on white and pastel fills. Excluding power leeches f...see more »Regarding power requirements, there is a hidden power leech in the 12V WS2811 pixels and strips- each controller IC still needs 5V, which is supplied by a zener diode and a resistor. Most of the idling power draw (no LEDs lit) goes into feeding all of those little zener voltage regulators, which really adds up for hundreds of pixels! The 5V versions (WS281201/12) don't have this issue..So for a little more money one could instead wire 3x as many 5V strips in the same area and get the same light output with more resolution and noticeably lower average power consumption. i.e. higher efficiencyA rule of thumb for RGB light arrays is that actual power draw will typically be about 1/2-1/3 of theoretical maximum unless the effects are heavy on white and pastel fills. Excluding power leeches for the controller ICs, that is.

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  • How to Make a Dehumidifier (Thermoelectric Cooling)

    OK, if you need only a small number of Watts of cooling power to effectively dehumidify a space and you can get your power free from the sun. So perhaps to control the humidity in a drawer, or small cabinet. Anything more than that, it still doesn't make sense.Many commenters here seem to think that could be enough to dehumidify a room, or even a whole basement. An average "room" dehumidifer uses about 500W, and the adjacent air and soil provides essentially unlimited fresh humidity into a space that's being actively dehumidified, so a duty cycle of 100% is not unusual. In the Northeastern US, it can easily cost hundreds of dollars worth of electricity to run a dehumidifer half of the year: http://www.cadmusgroup.com/wp-content/uploads/2012/11/Dehumidifier-Metering-Study-Matti...see more »OK, if you need only a small number of Watts of cooling power to effectively dehumidify a space and you can get your power free from the sun. So perhaps to control the humidity in a drawer, or small cabinet. Anything more than that, it still doesn't make sense.Many commenters here seem to think that could be enough to dehumidify a room, or even a whole basement. An average "room" dehumidifer uses about 500W, and the adjacent air and soil provides essentially unlimited fresh humidity into a space that's being actively dehumidified, so a duty cycle of 100% is not unusual. In the Northeastern US, it can easily cost hundreds of dollars worth of electricity to run a dehumidifer half of the year: http://www.cadmusgroup.com/wp-content/uploads/2012/11/Dehumidifier-Metering-Study-Mattison-050912.pdf A Peltier cooler is 1/3 as efficient, roughly speaking (yes, it really is TERRIBLE efficiency in comparison to mechanical refrigeration). So a comparable Peltier-based dehumidifer would need about 1500 Watts to do the same work.So if someone needs enough cooling power to justify even a very small commercial dehumidifier, and they would like to make the most efficient use of their spare solar panels it would be better by far to convert the DC output of the solar panels to AC using an inexpensive inverter, and use that to power their mechanical dehumidifer. A single Peltier device being used to draw moisture from the air is a nice demonstrator of the concept, but it is basically a toy for most of the applications where dehumidification is needed.

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  • How to Make a Dehumidifier (Thermoelectric Cooling)

    Despite a lot of hopeful comments here (maybe based on the false impression that Peltier devices offer high efficiency for cooling), any basement-scale dehumidification really would make more sense using a traditional compressor-based refrigeration system if it is to be affordable to operate, or for it to have sufficient capacity (as noted by JerryS42) without spending massive amounts of money on Peltier devices (and generating 3x the amount of waste heat in the process).How the cooling loops are arranged to collect condensation, or how waste heat is removed from the cooler, is more adaptable to personal choice and experimentation though.

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  • How to Make a Dehumidifier (Thermoelectric Cooling)

    @toddbatzler, reading through all of the comments it seems yours is the most honest and reasonable comment regarding the actual efficiency of this device. Many people seem to have no idea just how much energy is needed to dehumidify basements, etc. in humid climates. Peltier devices have been available for several decades, but never replaced traditional cooling systems for good reason! They are ONLY a better choice than mechanical refrigeration pumps when portability, small size, or quietness are absolutely required features and efficiency (and cost, in utility bills) can be sacrificed in exchange for these special cases. It is laughable to call any Peltier-based cooling or dehumidification device "efficient", unless perhaps comparing it to some even worse method - like repeat...see more »@toddbatzler, reading through all of the comments it seems yours is the most honest and reasonable comment regarding the actual efficiency of this device. Many people seem to have no idea just how much energy is needed to dehumidify basements, etc. in humid climates. Peltier devices have been available for several decades, but never replaced traditional cooling systems for good reason! They are ONLY a better choice than mechanical refrigeration pumps when portability, small size, or quietness are absolutely required features and efficiency (and cost, in utility bills) can be sacrificed in exchange for these special cases. It is laughable to call any Peltier-based cooling or dehumidification device "efficient", unless perhaps comparing it to some even worse method - like repeatedly baking out dessicant so that it can be used to "efficiently" remove humidity from a dank closet.

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  • starphire commented on taifur's instructable Convert $2 LED Lamp to $50 Smart Lamp5 months ago
    Convert $2 LED Lamp to $50 Smart Lamp

    It will be harder to find LED bulbs in the US that have this kind of direct-rectified power supply (it will also have half as many white LEDs inside, to match the lower voltage. Almost all LED bulbs sold here now use a better power supply in their base, which is also usually dimmable without flicker. So finding a bulb with this size and space inside may be difficult in some countries, or it may not be so compatible to control with your design. But it is a nice design for the bulb you have.It also looks like you can turn on both the white *and* the RGB LEDs at the same time using this app setup. However, I would caution against doing this for more than a minute or two, since the heat from the white LEDs and the 5V power converter will make the temperature inside the bulb hot enough to co...see more »It will be harder to find LED bulbs in the US that have this kind of direct-rectified power supply (it will also have half as many white LEDs inside, to match the lower voltage. Almost all LED bulbs sold here now use a better power supply in their base, which is also usually dimmable without flicker. So finding a bulb with this size and space inside may be difficult in some countries, or it may not be so compatible to control with your design. But it is a nice design for the bulb you have.It also looks like you can turn on both the white *and* the RGB LEDs at the same time using this app setup. However, I would caution against doing this for more than a minute or two, since the heat from the white LEDs and the 5V power converter will make the temperature inside the bulb hot enough to compromise the life of the RGB LEDs. This style of RGB LED is already pushed past its limits of heat tolerance at room temperature with all three LEDs inside at 100% power-the epoxy and long pins are poor heat conductors. It is not dangerous, but it is not good for reliable long life of one's handmade Smart Bulb. Best to keep using this bulb in open air, to help keep its temperature down and be kind to the electronics inside!

    If you begin with a white LED bulb which has only a bridge rectifier and capacitors to power it normally, then you MUST use a bulb made to operate at your country's AC line voltage-these type of cheap bulbs are not able to work on both 110V and 230V-a mismatch would either be very dim and flickery, or burn itself out immediately. They are actually getting hard to find in some countries (like the US), since they flicker so badly and even inexpensive LED bulbs from many sources now have tiny switching power supplies inside which convert to a much lower voltage to power the LEDs.

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  • A Guide for Buying LED's on E Bay ---- Part TWO

    In the sense that white LEDs are a rapidly evolving technology, there is much potential for confusion because what was cutting edge even a year ago is already becoming obsolescent, and design/manufacturing/sales simply can't keep all competitors at the same price/performance/quality - in that sense it is sort of a Wild West. That ALSO makes comparison reviews by organizations such as CR practically useless for specific models of LED bulbs, as they are being upgraded and replaced (and prices slashed) faster than their publishing cycles can possibly keep up to date with. The best they can do is to give general educational guidelines for consumers to do their own comparisons.And this is where labeling standards come in, as the FTC in the US has required that all LED bulbs adhere to a stand...see more »In the sense that white LEDs are a rapidly evolving technology, there is much potential for confusion because what was cutting edge even a year ago is already becoming obsolescent, and design/manufacturing/sales simply can't keep all competitors at the same price/performance/quality - in that sense it is sort of a Wild West. That ALSO makes comparison reviews by organizations such as CR practically useless for specific models of LED bulbs, as they are being upgraded and replaced (and prices slashed) faster than their publishing cycles can possibly keep up to date with. The best they can do is to give general educational guidelines for consumers to do their own comparisons.And this is where labeling standards come in, as the FTC in the US has required that all LED bulbs adhere to a standard labeling (since 2012) to allow consumers to do basic comparisons in store - just like a nutrition label.

    One danger with this approach is that it leaves your LEDs highly vulnerable to voltage spikes (which are more common than most realize, and usually absorbed by protective devices in modern power supplies). The peak *reverse* voltage on Light Emitting Diodes is usually low compared to bulk rectifiers designed for the purpose, so that can leave little margin for recovery from spikes induced by nearby lightning or inductive kickbacks from large motors, etc. For low cost holiday lights and such, they are not meant to last that long anyway.Whether 50/60 Hz or 100/120 Hz (putting a half wave rectifier inline), the flicker shows up in enough situations to make it undesirable to a lot of people as general lighting. A few companies have tried to commercialize the AC driverless approach with seri...see more »One danger with this approach is that it leaves your LEDs highly vulnerable to voltage spikes (which are more common than most realize, and usually absorbed by protective devices in modern power supplies). The peak *reverse* voltage on Light Emitting Diodes is usually low compared to bulk rectifiers designed for the purpose, so that can leave little margin for recovery from spikes induced by nearby lightning or inductive kickbacks from large motors, etc. For low cost holiday lights and such, they are not meant to last that long anyway.Whether 50/60 Hz or 100/120 Hz (putting a half wave rectifier inline), the flicker shows up in enough situations to make it undesirable to a lot of people as general lighting. A few companies have tried to commercialize the AC driverless approach with series LEDs in one package, with little success in the marketplace.

    I was just thinking that's one niche of LED product where "you get what you pay for" is NOT necessarily true. Tons of junk ads out there lately for really cheap, low quality "tactical lights" with extremely misleading or dishonest advertising pretending they are "military" grade, which is clearly targeted at people with no real experience of modern LED flashlights. They are actually charging MORE than a good brand name light from the store, for something imported in bulk from China for a tiny fraction of the cost of a decent one at the hardware store. It's predatory marketing that ensures you actually get LESS than what you'd pay for through local channels, yet some will still think it's an improvement on their ancient flashlight.

    With LED bulbs now selling for as little as a few dollars, even that's not really true anymore. But it's more complicated than that. There can be a variety of other reasons for choosing LED over CFL, including better performance in more directional types of bulbs (efficacy is a better measure than raw efficiency, i.e. useful light reaching the target vs Watts used, an area where ALL fluorescent type bulbs are at a disadvantage for directional lighting); to avoid the danger of broken glass and mercury contamination; better performance in more extreme temperatures (CFLs being slow to get to full brightness) and very short-cycle uses; higher risk of fire from aging CFLs (high voltage arcing). Theoretically much longer life as well, though that depends on the quality of design and manufactu...see more »With LED bulbs now selling for as little as a few dollars, even that's not really true anymore. But it's more complicated than that. There can be a variety of other reasons for choosing LED over CFL, including better performance in more directional types of bulbs (efficacy is a better measure than raw efficiency, i.e. useful light reaching the target vs Watts used, an area where ALL fluorescent type bulbs are at a disadvantage for directional lighting); to avoid the danger of broken glass and mercury contamination; better performance in more extreme temperatures (CFLs being slow to get to full brightness) and very short-cycle uses; higher risk of fire from aging CFLs (high voltage arcing). Theoretically much longer life as well, though that depends on the quality of design and manufacturing to some degree.

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  • starphire commented on Vulcaman's instructable DIY-SLS-3D-Printer9 months ago
    DIY-SLS-3D-Printer

    I completely agree about being extra careful with eye safety/goggles/shields for something like this.However, it would be overly simplistic to say that you can judge the blocking ability of laser safety goggles purely by their apparent color. If such goggles are relying solely on the colored dyes added to polycarbonate during manufacture, their ability to attenuate a laser in wavelengths they don't normally "pass" very well, they are not going to reduce the beam by very many magnitudes - a dark tinted pair of grey sunglasses could even in some cases be measurably more effective. Really high quality laser safety glasses are not simple colored gel filters in principle.

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