author
162CommentsBoston, MA USAJoined May 10th, 2006
Light seems to be a dominant theme in my interests.

Tell us about yourself!

Complete Your Profile

Achievements

100+ Comments Earned a bronze medal
  • starphire commented on arduinofanboy's instructable DIY Reflow Oven With Reflowduino2 weeks ago
    DIY Reflow Oven With Reflowduino

    This appears to be well thought out though my experience is that toaster ovens are not a great choice for reflow ovens. Regardless of how you control it, the internal temperatures are simply too uneven to get consistent results - especially if you are doing more than just a few small boards in the center of the oven. I gave up on the toaster oven eventually, after tiring of some boards in a batch being overdone (visibly singed) while those in a different part of the oven came out fine. A hotplate to directly heat small boards is fine, but not if you have a board that has any components on the other side or especially large SMT parts that don't heat as quickly that way (sucking the heat out at the solder point, requiring excess heating time for smaller parts).A small countertop convectio...

    see more »

    This appears to be well thought out though my experience is that toaster ovens are not a great choice for reflow ovens. Regardless of how you control it, the internal temperatures are simply too uneven to get consistent results - especially if you are doing more than just a few small boards in the center of the oven. I gave up on the toaster oven eventually, after tiring of some boards in a batch being overdone (visibly singed) while those in a different part of the oven came out fine. A hotplate to directly heat small boards is fine, but not if you have a board that has any components on the other side or especially large SMT parts that don't heat as quickly that way (sucking the heat out at the solder point, requiring excess heating time for smaller parts).A small countertop convection oven costs more than a toaster oven or hotplate, but the improved consistency and throughput, as well as faster cooling when needed (you still have to open the door) make it a worthwhile purchase for anyone who wants to make a versatile reflow oven for small batch production.

    View Instructable »
  • starphire commented on GreatScottLab's instructable DIY WiFi RGB LED Lamp1 month ago
    DIY WiFi RGB LED Lamp

    Nice work on the electronic design and integration to wireless control. It is clear that you put a lot of thought and care into the electronics and mechanicals here.So I am surprised that your approach to the thermal management of the LEDs is so casual in comparison. Having done a number of design and test cycles on similar high power LED fixtures, I would never have your confidence that they will last a long time in this arrangement!Even in open air, that would be a minimal heatsink to properly cool 5 Watts of LEDs continuously, let alone 10 Watts. But it's worse when the heatsink is in an unventilated enclosure without even a fan to help cycle the air inside. And the assembly is placed on top of a power supply module that is also generating heat. That 12W output power supply may be 80...

    see more »

    Nice work on the electronic design and integration to wireless control. It is clear that you put a lot of thought and care into the electronics and mechanicals here.So I am surprised that your approach to the thermal management of the LEDs is so casual in comparison. Having done a number of design and test cycles on similar high power LED fixtures, I would never have your confidence that they will last a long time in this arrangement!Even in open air, that would be a minimal heatsink to properly cool 5 Watts of LEDs continuously, let alone 10 Watts. But it's worse when the heatsink is in an unventilated enclosure without even a fan to help cycle the air inside. And the assembly is placed on top of a power supply module that is also generating heat. That 12W output power supply may be 80-90% efficient, so it can add a few Watts of heat as well. Adhesive silicone thermal pads are a compromise in heat transfer for assembly convenience and/or electrical isolation, never for the best heat transfer. A good thermal paste would do better, since you don't need to worry about electrical isolation in this case.I realize there are *many* Makers and enthusiasts who undersize the LED heatsink, and conclude that it "feels" OK to touch so it must be working. Everything seems to be working fine as they write up and publish their design for others to copy. If some of the LEDs start to fail after 100 or 1000 hours, they are usually quick to blame a poor quality LED module rather than consider the possibility that the junction temperature of the LEDs was exceeding its limits on a regular basis. The methods and formula for calculating Max. Tj from known parameters are not difficult to apply, and easily confirmed with a thermocouple in the fully assembled lamp. I would strongly recommend doing that, you may be quite surprised at the extrapolated junction temperatures on full power!

    View Instructable »
  • starphire commented on Professional Amateur's instructable Eagle Eyes Visor1 month ago
    Eagle Eyes Visor

    Nice design, but maybe you could tell us where does the average person find a gold sputter machine? I'm guessing that's not something one would buy just to make some novelty glasses...

    View Instructable »
  • starphire commented on ChrisG76's instructable DIY PVC LED Landscape SpotLight1 month ago
    DIY PVC LED Landscape  SpotLight

    I think you've succeeded at making this low-cost and easy to make. But it doesn't seem to have anything to discourage water from dripping straight down into the bulb and socket. Commercial garden lights of this style usually have a splashproof window to keep the electrical components relatively dry.For low voltage LED lights, that might not create a safety hazard. But GU10 and E26/7 sockets are meant for line voltage AC, and even if you use LED light bulbs rated for "Outdoor" use they aren't necessarily designed to handle water splashing directly on them. I'd be concerned about safety, not to mention reliability, before putting these outdoors where they might get wet.

    View Instructable »
  • Arobodude's DIY Burning Man Evaporative AC Swamp Cooler

    I've seen a hundred variations on swamp coolers since the 1960s (when I started paying attention to them), including homemade ones in a variety of housings. When you say "the original design is mine", I'm curious what innovation in particular sets your original design apart from all its predecessors? Is it the orange bucket? :)

    View Instructable »
  • starphire commented on GreatScottLab's instructable Make Your Own POV LED Globe2 months ago
    Make Your Own POV LED Globe

    If the imbalance is due to the electronics at the center that would certainly help. Though for best stability, I would start with a sturdier frame design. Whether using steel, aluminum or even wood, using just flat stock without cross bracing or gussets will tend to be wobbly at any speed.

    View Instructable »
  • starphire commented on JoeM114's instructable Back to School LED Strip Automation2 months ago
    Back to School LED Strip Automation

    You use the TIP31? The TIP series of transistors are still useful and popular, but they are not "MOSFET" devices no matter how you look at it. It seems ironic that that you caution readers about getting MOSFETs with suitable gate voltage when you're not actually using them. How did you manage to transpose Gate, Drain, Source in your drawing to the TIP31's actual pins for Base, Collector, Emitter and get it to work without noticing the difference?

    View Instructable »
  • starphire commented on Magnetic Games's instructable Ferrocell, Magnetic Fields Viewer5 months ago
    Ferrocell, Magnetic Fields Viewer

    I love this project! Thank you for sharing.Until today, I never knew that WD-40 has mineral oil as a main ingredient. But it seems there are other important ingredients in it as well.Have you tried this with regular mineral oil? Will that work as well?Also, will any ferrofluid work, or do the ferrous particles have to be a certain size?

    View Instructable »
  • DIY Cathode Ray Tube: Interacting With Electrons

    This Instructable DOES have useful instructions for home experimenters wishing to make a high voltage discharge tube. It DOES NOT result in a "Cathode Ray Tube", for multiple reasons described below. Please do not call it that! It is simply not correct terminology for what this is, and you will only confuse people getting started in this field.First, the common flyback-type power supply used here actually generates a high-frequency pulsed AC output, essentially a Tesla coil with a solid state oscillator on the primary. There is no rectification, smoothing or reference to ground at the high voltage side. There is no "anode" or "cathode" terminal, so in reality the discharge is flowing in both directions between the electrodes - exactly like a neon sign or fl...

    see more »

    This Instructable DOES have useful instructions for home experimenters wishing to make a high voltage discharge tube. It DOES NOT result in a "Cathode Ray Tube", for multiple reasons described below. Please do not call it that! It is simply not correct terminology for what this is, and you will only confuse people getting started in this field.First, the common flyback-type power supply used here actually generates a high-frequency pulsed AC output, essentially a Tesla coil with a solid state oscillator on the primary. There is no rectification, smoothing or reference to ground at the high voltage side. There is no "anode" or "cathode" terminal, so in reality the discharge is flowing in both directions between the electrodes - exactly like a neon sign or fluorescent light does. You would need a high voltage diode and capacitor after the secondary winding to get a DC output, which is a fundamental requirement for generating Cathode rays.Second, the refrigerator vacuum pump is good for experimenting with low-pressure gas discharge tubes, but they are far from being able to generate the high vacuum necessary to generate electron beams. The good news is, this also makes this tube safer to be near, as it is not an efficient X-ray generator. The bad news is, the high-voltage discharge inside the tube is randomly shaped, like a lightning bolt. The discharge is principally using gas ions (mostly nitrogen and oxygen nuclei) going through excited states, not electrons! It is possible to influence the ion discharge with an external magnet using a tube like this, but not to control it in a repeatable way.Third, an essential part of the Cathode Ray tube concept is to have a fluorescent screen at the cathode end to visualize the impact of the electrons flowing toward it. Without a fluorescent screen, it would be a Crookes tube (assuming the first and second conditions above were met). Which is a predecessor to the CRT.Finally, normally a separate heating filament would be used to reduce the breakdown voltage required to reach a distance between anode and cathode - this was standard in vacuum tubes and fluorescent lights - making them a "cold cathode" tube (sort of confusing, as these are usually AC driven as well, so both electrodes can be the cathode).It's great that you want to share your enthusiasm, and it's a good starting point. But please reconsider the name of this project - it is absolutely NOT a CRT or a CRT demonstrator. It is a high voltage discharge tube, or a Geissler tube if you want to be fancy about it. :-)

    There would be some low energy X-rays coming out of it, much as with any high voltage spark gap or a neon tube. But the pressure is much too high to make it a dangerous source of such radiation. It's primarily a discharge tube, the 'beam' is visible as gas ions relaxing from an excited state, not an electron beam.

    Nophead is correct. It is mostly nitrogen ions giving off visible light as they return to a lower energy state. Though there would also be some oxygen, argon, CO2, etc - everything we have in the atmosphere. A spectroscope could be used to detect emission lines from the different gases in the tube. There are also electrons in the tube, but their movement is not directed as they would be in a CRT.

    View Instructable »
  • starphire commented on watchmeflyy's instructable LED Firefly Earrings6 months ago
    LED Firefly Earrings

    I love this design!Following the tradition of LED "throwies" made with lithium coin cells and LEDs, there's no need to add a resistor to them. First, these coin cells have a fairly high internal resistance which automatically limits the current flow you can get out of them (and this also drops as the battery wears out). Second, the green, blue, UV, and white LEDs most likely to be sold today have a higher forward voltage (more like 2.5V) than the 1.7V cited, which is more usual for red, amber, yellow and some older green LEDs. But these can still usually handle the current without a resistor, due to the internal battery resistance. If a larger battery or DC power supply is used, then a resistor is definitely needed though.For the most "firefly-like" LED color, I'd su...

    see more »

    I love this design!Following the tradition of LED "throwies" made with lithium coin cells and LEDs, there's no need to add a resistor to them. First, these coin cells have a fairly high internal resistance which automatically limits the current flow you can get out of them (and this also drops as the battery wears out). Second, the green, blue, UV, and white LEDs most likely to be sold today have a higher forward voltage (more like 2.5V) than the 1.7V cited, which is more usual for red, amber, yellow and some older green LEDs. But these can still usually handle the current without a resistor, due to the internal battery resistance. If a larger battery or DC power supply is used, then a resistor is definitely needed though.For the most "firefly-like" LED color, I'd suggest searching for a particular version of older type green LED called an InGaAlP (these are the abbreviations of the elements used to make them), which are usually packaged in green epoxy. You can also sometimes find them in a smaller diameter, 3mm case, which would be an even better fit with something this small. These are fairly high brightness, with a yellow-green color very close to real fireflies! Traditional electronics distributors (such as Digi-Key) or eBay dealers selling old surplus parts should still have them.

    View Instructable »
  • starphire commented on mrstan's instructable Repair Dead COB LED Light Bulbs7 months ago
    Repair Dead COB LED Light Bulbs

    I was utterly mystified by your comment, since every single reference to COB I've seen in the my industry (electronics) for over 25 years has explicitly been paired with "Chip-On-Board", and in fact if you do an internet search of these words together there are millions of examples to prove this. However, if you google "COB Crystal on Base", there are also a great many hits - except that every single one of them is for cheap chinese LED bulbs using LED COB arrays. An industry that simply didn't exist even 5 years ago . So you are both correct, in some sense. But no engineer ever refers to LED chips (or dies), even those on sapphire substrates, as "crystals". That sounds like something that was made up by factory workers and wholesale dealers in a country w...

    see more »

    I was utterly mystified by your comment, since every single reference to COB I've seen in the my industry (electronics) for over 25 years has explicitly been paired with "Chip-On-Board", and in fact if you do an internet search of these words together there are millions of examples to prove this. However, if you google "COB Crystal on Base", there are also a great many hits - except that every single one of them is for cheap chinese LED bulbs using LED COB arrays. An industry that simply didn't exist even 5 years ago . So you are both correct, in some sense. But no engineer ever refers to LED chips (or dies), even those on sapphire substrates, as "crystals". That sounds like something that was made up by factory workers and wholesale dealers in a country where English is not their first language, to explain the term for a process which is now widely used in lighting products. Nowhere else.

    The diode check function on some multimeters either uses too little current or too low a voltage (must be >3V) to visibly light LEDs. I have an older, but very good quality, multimeter which has this limitation but my cheapo backup meter works fine for this purpose.The simple capacitive dropping circuit using the 'candy' cap does not do much to absorb voltage spikes. In fact, the kinds of voltage transients that damage electronics are much too fast, often peaking at voltages much higher than the capacitor is rated to handle. There are devices which *are* capable of protecting the LEDs from these transients, such as MOVs and TVSs, but they are never included in these cheap LED bulbs.When one of these transients goes through the string of LEDs, the chip with the weakest insulating barr...

    see more »

    The diode check function on some multimeters either uses too little current or too low a voltage (must be >3V) to visibly light LEDs. I have an older, but very good quality, multimeter which has this limitation but my cheapo backup meter works fine for this purpose.The simple capacitive dropping circuit using the 'candy' cap does not do much to absorb voltage spikes. In fact, the kinds of voltage transients that damage electronics are much too fast, often peaking at voltages much higher than the capacitor is rated to handle. There are devices which *are* capable of protecting the LEDs from these transients, such as MOVs and TVSs, but they are never included in these cheap LED bulbs.When one of these transients goes through the string of LEDs, the chip with the weakest insulating barrier (which is microscopically thin) burns through, usually creating a near-short through that LED. After this repeats a few times with more transients, the failures come faster and faster until there is finally an open circuit somewhere.So we can keep taking these bulbs apart and repairing them (until all the SMT packaged LED bulbs have been replaced by true COB ones), but the failures will never stop without better voltage transient protection.

    Thank you for pointing these facts out. It does appear that dealers in China have now muddied up the term "COB" to mean something else in their business, but only for LED arrays.And yes, the 'candy' cap is just a simple dropper circuit, although it does have a slight smoothing effect on some kinds of voltage transients. Ironically, the lack of true voltage clamping circuitry for fast voltage spikes (which occur on AC lines at random times no matter where you live) is OFTEN what destroys the LEDs in cheap bulbs!

    View Instructable »
  • starphire commented on darbinorvar's instructable Super Bright Tunable Led Light Panels7 months ago
    Super Bright Tunable Led Light Panels

    The design of the power system for multiple panels is clever, but since it allows both colors of LED strips to be ON at the same time it can eliminate any benefit from using the aluminum as a heatsink. To function as a heatsink there must be an increase in cooling surface area. When only one color is used, the alternating strips which are turned off can radiate some heat from neighboring strips which are turned on. But if both colors are on at the same time, there is only a little bit of exposed aluminum at the edges of the panel, and metal this thin does not allow heat to travel laterally very well. In this situation, the copper in the LED strip is actually more efficient as a heatsink than the aluminum sheet behind them.If the whole panel is enclosed in a fairly insulative material su...

    see more »

    The design of the power system for multiple panels is clever, but since it allows both colors of LED strips to be ON at the same time it can eliminate any benefit from using the aluminum as a heatsink. To function as a heatsink there must be an increase in cooling surface area. When only one color is used, the alternating strips which are turned off can radiate some heat from neighboring strips which are turned on. But if both colors are on at the same time, there is only a little bit of exposed aluminum at the edges of the panel, and metal this thin does not allow heat to travel laterally very well. In this situation, the copper in the LED strip is actually more efficient as a heatsink than the aluminum sheet behind them.If the whole panel is enclosed in a fairly insulative material such as wood and covered with acrylic, all of the heat from the LED assembly is somewhat trapped inside the box. The strips will still work, but the risk of early failures and a greatly reduced lifetime for the LEDs should be expected. Some ventilation holes in the side of the box would go a long way towards controlling the heat buildup in this design.In sum, if building a color tunable light box like this it should be noted that prolonged use with both colors at high power will not be good for the life of the LEDs, and modifications to increase ventilation or perhaps some fresh air flow to the back of the aluminum panel would help ensure long term reliability of the panel.

    View Instructable »
  • starphire commented on sjowett's instructable Mega Torch - the ultimate guide9 months 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.

    View Instructable »
  • 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.

    View Instructable »
  • starphire commented on JuanF92's instructable NeoBulb (Neopixel bulb with sensor)9 months 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.

    View Instructable »
  • starphire commented on rdrew5's instructable LED RGB Light Painting Light Spinner9 months 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!

    View Instructable »
  • starphire commented on Jules1050's instructable PlexiClock10 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!

    View Instructable »
  • starphire commented on Jules1050's instructable PlexiClock10 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.

    View Instructable »
  • starphire commented on Gelstronic's instructable POV Globe 24bit true color and simple HW10 months ago
    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.

    View Instructable »
  • 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.

    View Instructable »
  • starphire commented on akolk1's instructable Huge addressable RGB LED (ceiling) panel1 year 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.

    View Instructable »
  • 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.

    View Instructable »
  • 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.

    View Instructable »
  • 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.

    View Instructable »
  • starphire commented on taifur's instructable Convert $2 LED Lamp to $50 Smart Lamp1 year 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.

    View Instructable »
  • 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.

    View Instructable »
  • starphire commented on Vulcaman's instructable DIY-SLS-3D-Printer1 year 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.

    View Instructable »