Search for wavelength in Topics


increasing wavelength?

Is it plausible to increase the wavelength of, say, infrared light? I have a 808 nm 1 watt laser and i am struggling with researching if it is plausible to do so, and if it is then how it would be accomplished?

Question by Nexoid    |  last reply


Why do the constituent of white colour have different wavelength?

When white light passes through a prism,it is splitted into its constituents colours due to the difference in the speed of different colours in prism.the colour which has more speed is deviated most(red)and the colour having less speed deviates least(violet).thus,white light is splitted. we know that wavelength is directly proprtional to speed. The question is why the wavelength of different colours differ from each other?and why does the wavelength of red colour is longest and of violet colour is shortest? 

Question by vmkverma    |  last reply


UV led? Answered

Hi all../ Please  help me by tell me what  kind of UV led ( the  WAVELENGTH) for better see water glow in the dark ( water + highlighter pen ) with this color (please see photo)Because in Ebay sale some different UV led  wavelength 390 to 410 nm . Many thank you.

Question by lam    |  last reply


Is there a LED with adjustable Wavelength and color?

I just need a LED that can give me desired color and wavelength (in nm). I just googled but found nothing. Hope I will find one. Thanks in advance.

Question by Dasaradh M S    |  last reply


Solar Cell Light Absorption. Answered

What wavelengths of light get absorbed into a standard monocrystalline solar panel? (I.e. infrared, red, blue ultraviolet)  I think it is ultraviolet but I can’t clarify this online. .

Question by physics_dude    |  last reply


Is this derivation RIGHT(physics)? Answered

Hi to whoever is reading this.Yesterday me and my friend derived an expression relating mass of a photon and its frequency .Can anyone tell me if its right?Ps I'm only 15 years old so i may not be right . Here is the link for it: the folder name isPMF.docx and anyone can view it https://drive.google.com/file/d/0B391sIgwIxyvZ196MmtMTFJFa1k/edit?usp=sharing also thank you in advance.

Question by Strontium    |  last reply


How do you determine the length of an antenna and the size of a fractal antenna? Answered

In an instructable, the formula for calculating antenna length was given as "length in meters =300 / frequency in MHz".  The example given was for a Bluetooth antenna with a frequency of 2450MHz.  The antenna length was calculated as 300/2450 = 0.1225m = 12cm.  The author then divided it by 4 to make a "quarter wave" antenna length of 30mm.  Why divide it by 4 and what is the benefit of a "quarter wave" antenna.  What is the effect of the conductor leading to the antenna?  If the 30mm antenna is soldered to a 4mm lead, does that result in a 34mm antenna?  For a fractal antenna, should the 30mm length of wire be folded into a fractal shape or should the total fractal antenna be 30mm in width?  I have read somewhere that one of the benefits of a fractal antenna is that they are able to receive signals of different wave lengths.

Question by fcampbell    |  last reply


Antenna length for a frequency modulated signal.

I  am given to understand that the length of an antenna is proportional to the wavelength of the signal that is fed to it (a quarter wavelength, for example). In the case of a signal modulated by amplitude, the frequency (and therefore wavelength) of the carrier wave remains unchanged. However, in the case of a signal modulated by frequency, the signal fed to the antenna will vary in frequency (and, therefore, wavelength). My query is this : how would one go about calculating the length of an antenna for a frequency modulated signal? Its frequency is not constant, so to construct an antenna of say, a quarter of the wavelength, would be impossible. I thank you in advance for your assistance. AlexHalford

Question by alexhalford    |  last reply


Halogen to LED.?

Right now i'm working on photo spectrography, and using a halogen lamp because of the wavelength it outputs. The thing is, we are trying to make a more portable version of this, is there a type of LED or an array of them, that i could use for this? Take in mind that the LEDs have to output a wavelength very similar or equal to that of a halogen lamp.  

Question by joreknight    |  last reply


What happens when you induce two currents of differing wavelength on the same line? Answered

If I induce two currents of differing wavelengths on a single conductive body, say an iron pipe for example, how can I calculate what the resulting signals wavelength will be? Is it as simple as taking the root mean square of the frequency of the signals? Any ideas for calculating the voltage of the final signal? ------------------------------------------------------------------------------------------------------------------------- Example: Signal 1: 60hz at 100v Signal 2: 75hz at 100v RMS frequency sqrt(((60^2)+(75^2))/2) =  67.9153 ------------------------------------------------------------------------------------------------------------------------- Thanks  a bunch!

Question by paulcauchon    |  last reply



What wavelength UV LED do I need? (and cheap source for them)

Alright less of what kind I need more than what will work. I want to buy one of those LED work lights (that go for around 40 bucks) to UV, however according to this list I would need 365 nm LEDs http://www.riskreactor.com/Black_Lights_UV_LEDs/Black_Lights_UV_LEDs_Main.htm so my question is, would it be better to go with 365 nm? Thing is those are way more expensive than 380 nm leds, but you can do some neater stuff with them. So, would it be worth spending the extra on them,  and do any of you know a place I can get them that don't charge a ridiculous amount for them? Also, would it be a good idea to perhaps mix the LEDs that way I get the stuff you can do in 380 nm and 365 nm? would that work?

Question by XOIIO    |  last reply


will this laser burn?

i can get a green laser with: Output power: 50mW, wavelength: 532nm it appears to be a nice laser but im more intrested if it can burn stuff. will it? Thanks , Hackoslash

Question by Hackoslash    |  last reply


Heavy duty UHF CB radio antennas and why cheap can be much better....

If you not a fan of normal road cars then you might get some 4WD and go off road every now and then.There are even those doing trips to remote locations that take a few weeks.An essential piece of equippment these days is a UHF radio.In a convoy you might get away with a handheld one if the cars are not too far apart and the terrain suitable.Most peole however opt for a permanent installation in the dash or roof console.After that decision comes the hardest and often costly part: What antenna to use....If you trust certain online reviews and manufacturer claims then one thing becomes quickly obvious.If you need a sturdy and powerful antenna then you have to pay top dollar.Some come with heavy spring bases claiming to protect the heavy fibreglass rod if you hit a bush or trees branch.There is always a compromise between weight and stability.And trust me, on the right corrugations you prefer not to look at your antenna....So how are these expensive antennas made?As I don't have any own pictures and don't want to steal them from the net: Please search for the terms used if you don't know them already.To answer this let me go to the other types of antennas you can get for your UHF radio.There is the famous rubber ducky - a stubby antenna best suited for short range on difficult terrian.Then we have the fibreglass whip antennas that have more or less coils integrated or even consist of one single coil with different spacings in sections.Good for normal road use, not so much off road as they won't tolerate too much vibration, they often snap off the base screw.Most people now just ignore the short whip antennas of 15 to 30cm length as they usually only come with a gain of around 4.5-6db.I will explain later why that might be a misconception.The last ones are those steel whips with one or two "loading" coils.These coils electrically shorten the antenna.They also provide a matching to the 50 Ohm required for most transmitters and antenna cables.Usually they are designed to be 5/8 Lambda antennas.A good antenna for just receiving, like when using a scanner is not critical in length.Transmitting however means you need a proper Standing Wave Reflection or SWR ratio.For this the antenna needs to be tuned.To be of any good use your antenna needs to match the transmitting frequency.This works best if the antenna length is at 1/2, 1/4 or 5/8 of the corresponging frequencies wavelength.Also called Lambda if you look for antennas.In the good old 27-MHz days we were used to quite long antennas in our backyard, for the car we then opted for 1/4 of this - usually around 2m in length.For UHF however 1/4 wavelength already means you are down to about 16cm...Going for 1/2 is a good thing here as it is still quite short at about 34cm.Real difference when it comes to these Lambda factors is the radion angle produced.You can imagine a 1/4 to look like a huge donut with no hole, about 25° for the radiation angle.At 1/2 this will be flattened out to around 20°.A 5/8 Lambda ntenna can get as low as 16°.Imagine it like a flashligh that has adjustable focus.The light source is of fixed output as your transmitter.The lens does the job of the antenna.If you make the beam more narrow then the light intensity of a certain areas at a certain distance will increase.Means for the radio you get a longer distance your signal can travel with enough energy.This however comes at a price!Imagine you are at the bottom of quite stepp mountain and your mate is up on the top about 2km above you.A high gain antenna with a narrow radion pattern might not even reach up there, while a short stubbie with just 3db still has a chance due to the more spherical radiation.Also explain why low gain and with that short antennas work best in hilly terrain...Back to the thick ones...As you can see you can basically hide any type of whip antenna into a fibreglass rod.But most of the are as said "ground independent", means unlike your normal whip they don't need the spring or foot to be of low resistance to your car's body.How does that work?Well, exactly like these ground independent whip antennas with a spring base or metal pole base work.You know the earliest antenna was a dipol - look it up on Wiki ;)For our CB radios that means you have a metal rod or spring that is about 1/4 or in some cases 1/4 of the wavelenght long.This is connected to the shielding of the coax cable and provides the required ground for the mounted antenna.The big difference is that only too often a dirt cheap dipol is hiding in your expensive fibreglass rod ;)The complete antenna might bring over 2kg on a scale, but the actual thing allowing you to receive and transmit is a few grams of coax cable...HOLD ON A MINUTE!! Some will say now...My whip is 70cm long and my expensive heavy duty one with 9db is 2m long - how does that work with your wavelength theory??Well, it is not my theory, just a fact ;)Imagine a 1/4 Lambda dipol, then it would be all up around 35cm long.And funny enough, that is about the length of a $180 heavy duty stubby if you just tak the rod itself.Go 1/2 of Lambda and you get an overall length of the dipol of around 65cm - add the metal rod making the crew that holds the fibreglass rod and you have the common 70-75cm heavy duty antenna...Anything above this length usually is either just a long rod with noting above the 75cm mark or simple has the 75cm long dipol made from the coax cable at the top with the antenna cable going down the otherwise empty rod.Ok, I got it, either 1/2 of the wavelength or 1/4, so about 35 or 16cm long.Ground independent we add either 1/4 for the spring base and rod or 1/2 for the longer ones.And how again does it work with the gain of an antenna?If you trust Wiki then it comes down to the radiation pattern.These heavy duty antennas usually come with around 6 or 9db, the short ones with 3-4.5db.These values might give you an indication about the theoretically possible distance you can transmit but nothing about the terrain it is suited for.Common rules of thumb created by those selling antennas and radios is that you a high gain antenna on flat terrain and a low gain antenna in a hilly area.Around 4.5-6db seems to be the golden ratio here as these anteannas are equally bad for both extremes in terms of terrain options.What you really would need to know is the actual radiation patterns in a three dimensional plane.A straight whip or dipol as a more or less donut shapead radiation pattern.However, location affects this!Mounted in the middle of the roof it is closest to perfect, while at the corner of your bumper bar you will distord the donut and also block parts out with the body of your car.This is why for this type of mounting elevated antennas are prefered.Makes no sense to have a 16cm long stubbie mounted so the top is still lower than your bonnet...Any antenna with a loading coil (or several) or top load will have a distinctively different pattern.We speak of so called "lobes".If you see it in 2D then for example a 1/2 lambda straight whip will look a bit like the infinity symbol.A 1/4 Lambda of the same style looks more like two ping pong bats joined without the handles.Those with loading coils or linear arrays made from coax cable however can produce multiple, prefered lobes.Usually they are in the 4-6db range and claim to be "universal" or as "allrounder".Here you get a quite narrow main lobe of 12-16° with one or more but much shorter lobes going upwards at about 10-30° depending on the configuration.At short range, like in hilly terrain both lobes overlap while you get a dead area at greater distances.You can sometimes notice that when you are on a low level talking to someone up high.There are cases when with a bit more difference in angle to each other (in terms of height and distance) the signal jumps up a few numbers.You just went from the dead zone into the lobe ;)With just a db value for the anteanna but no details about the actual design, heavy duty antennas can fool you badly.In mayn cases a 1/2 Lambda straight whip on the roof will outperform a costly, heavy duty antenna mounted to your bullbar.This is the reason why the expensive ones are the biggest cheat - they just elevate a quite small antenna above your roof line.And since it is heavy it needs a big spring and you hope it will not break if you hit something on a narrow track.All while the thin stainless stell whip with the cheap magnetic base just flexes under all obstacles with no damage at all.Plus, if you really get into the thick jungle you can just take the magnet off until you are through LOLWhy is a SWR and power meter still an important tool to invest into?Those remembering or still using 27-MHz radios only know too well why you need a proper SWR and power meter.With the lenght of the antenna at these low frequencies and affecting factors new the antenna proper tuning is a must.The bandwidth of the channels also means you have to tune the lowest and highest channel so the are basically even, anything else and the old guys would scream "UNACCEPTABLE!" ;)Especially it you want to get the last out of your system without going illegal.For some reason we accepted the claims that an SWR reading of around 1:2 is fine and acceptable.Most of the radios lower the power output to protect the transmitter if the SWR goes to far out.Allows for simple mass production of antennas with fixed cable lengths that are usually well overpriced.The most expensive bit is the cable itself here...I had no time to build an analog SWR and pwoer meter that works properly on 27 and 470MHz, so I ordered cheap SW30 from China.With that I first checked my little collection of antennas then those of some of my friends.This includes everything from short rubber duckies over loaded and straight whips to heavy duty models.One thing that was obvious right away: most are far away from an SWR readin anyone with a 27MHz groundplane antenna on a long mast would accept.And only one heavy duty antenna had a SWR readin of below 1:1.6 for channel 1 AND channel 40!That one was relatively cheap noname brand.With that sorted I decided to tune at least my steel whip antennas.To my utter disappointment they were all just a tiny bit too short - a thing that would have caused a proper 27MHz antenna manufacturer to to keep a large stockpile of his antennas...I had one though that was longer than needed.And before you ask: Yes, I tested them on both my elevated bullbar mount AND a direct mount on the roof rack.Did not change much for the bad ones so I ignored the mounting position for the tuning.I checked the power once for both channels on my prefered antenna and got 4.4W.Mind you that one has a SWR reading of 1:2.2 and will no longer be used as I can't be bothered to make it longer.For some reason I thought I check the SWR and power everytime I cut a bit off the antenna instead of just watching the SWR reading.At original length I had a SWR of 1:1.9 on ch40 and 1:1.75 on ch1 with 4.6W.I kept trimming down by about 2mm increments until I got an even readin of 1:1.07 on both channels.And with every trim the power went up a little bit.I have a friend that is or better, was just at the brink of being unable to reach from my driveway when he is parked in front of his house.A radio check after the tuning revealed that instead of coming with a lot of static noise and sometimes cut out I got a solid reading of 2 on his end with a much more acceptable level of noise.However, I still struggles as badly to hear him...Funny thing is that test was with just a plain and straight whip of 1/2 Lambda, in my case the tuning resulted in a length of 38cm from the base of antenna screw to the tip.My fancy 9db high gain antenna that is just over 70cm long did not even reach him while I could hear him slightly better than on my tuned one.Changing the mounting to the roof rack gave me a clear reception and a signal strength of 4 at my friends end with no noise.Elevation and nothing around the antenna does matter...After all this, would I still bother to buy a ready to go antenna for 470MHz?Only if I had to.Getting some RG58 cable or re-using it from on old antenna is cheap enough.A standard screw mount with a grub screw to hold a steel whip sets you back less than 10 bucks, from China even cheaper.And most will find a soldered on connector on the other end of an old antenna to be salvaged if required.If you don't have any sring steel wire of about 40cm length then think out of the box ;)The packing of pillows and such often come with a sring steel wire to make the plasitc floil keep its shape, some old suitaces have thicker wire doing the same.And if you ask nicely you might get a bristle or two for free from a street sweeping machine at your councils depot ;)After all we only need a maximum of 40cm to have enough left to trim and tune down.What is left to do?Of course some distance tests to check how well such a simple antenna really really works in comparison to commercial models.I only have one 9db antenna and will check it first to see if on flat terrain there is much difference in distance for transmitting.Unless this difference is well above one kilometer I will not bother with a high gain antenna like this anymore and instead opt for a longer mast and 1/2 Lambda.Another thing on the to do list to try a ground plane antenna with topload to squeeze the radion lobe down to under 15°.The resulting antenna would be quite short here and using an elevated mast is a must have to get over roof level with at leat a few wavelengths of distance to the roof.I guesstimate that an optimised antenna of this style should result in a distance increase of about 10-15km of flat terrain while being utterly useless in a hilly areas.Plus, such a design is not really suited for a vehicle going fast on a freeway, so it will go on my house instead.

Topic by Downunder35m  


possibility of Wave Change?

This theory states (my own be exact) that a certain wavelength can become an amorphous solid using a certain gas, a friend of mine agreed with me. What is your opinion on this matter?

Topic by crc09    |  last reply


Variable wave laser devices? Answered

Are there any lasers available to the general public capable of changing wavelength? If so, where can I get one? Is there an easy way to make one?

Question by DIY Emilio    |  last reply


Antenna for 434 MHz ASK RF transmitter module? Answered

Hi, I have these few questions regarding aerials that can be used with a 434 MHz ASK RF Transmitter module. https://electrosome.com/wp-content/uploads/2014/10/MO_SAWR.pdf  (data sheet of the transmitter) 1)The recommended length for the antenna is 17 cm,which is a quarter of the wavelength. Will using a 34 cm antenna(half wavelength) enhance the range of transmission? Will it get even better for 3/4 th and full wavelength long antennas? 2)Should the antenna be a monopole? Can I use a helical one instead(picture attached)? What are the ideal dimensions of a helical antenna(with respect to its wavelength) for maximum range ? Should the antenna of the receiver be of the same type or can I have a helical transmitter antenna and monopole receiver antenna ,both of same length? 3)Does Copper traces on the printed circuit board between the antenna pin of the transmitter and the actual antenna,add to the total length of the antenna? If the answer to the previous question is yes,can using coaxial cables to connect the antenna pin to the antenna prevent this from happening? 4)Should the antenna be installed perpendicular relative to the plane of the circuit board?Has it got anything to do with grounding or anything? Should the antenna be grounded too and if so how?(I am a bit confused with this part) 5)Can having the antenna in close proximity to step down transformers and ics ,produce undesired results?

Question by Adarsh_tronix    |  last reply


How can I get a filter whose color depends on the polarization angle?

Suppose you have a filter through which light linearly polarized at a 60` angle looks red, 120` looks green, and 180` looks blue. A mixture of 60` and 180` looks purple (red+blue). Unpolarized looks white (red+green+blue).Does someone make such a filter? Or one that only polarizes light in a narrow band of wavelengths and transmits other wavelengths unpolarized? Or can you think of a way to capture this information in a photo without specialized equipment or taking multiple pictures?

Question by NobodyInParticular    |  last reply


What type of light do I need to help with S.A.D.? Answered

I was wondering what type of light source could I use for S.A.D.. Compact fluorecent, LEDs , and which colour? Is there a specific wavelength?

Question by ChrysN    |  last reply


Do Ultraviolet rays travel faster than Light? Answered

Because Ultraviolet Rays have higher wavelengths than the visual light spectrum. Does that mean that Einstein's wrong, or did I miss something and am I stupid?

Question by Wasagi    |  last reply


Anyone tried a (true) UV LED based moth trap?

I have also commented on a seemingly related old dead thread but hope for better luck here. Firstly, did anyone ever make any progress with building and successfully using an LED based moth lure/trap? Secondly and if yes, any advice? I am currently in the process of building a lure/trap that will use reflected wavelengths (interchangeable LED head) based on the principle that Moths (as pollinators) and flowers (as pollinatees) see and reflect UV light respectively and if that is true then surely i can take advantage of this to build a targeted trap to trick the moths in. note i will be testing UV wavelength (365nm), violet (400nm) IR and white LEDs.

Question by BDen    |  last reply


How would I make a simple Infrared Heater?

I am planning on build ing IR Heater. would a 6 millimeter IR emmiter with 960 millimeter wavelength work to produce heat? If your not aware with IR heaters then here is a short explanation: A normal heater such as a gas heater heats up the surrounding air, but a IR heater uses infrared waves to heat up surfaces of objects. So instead of heating surrounding air the IR waves heat up surfaces of objects. Also IR waves penetrate the epidermise (top layer of skin). Here is a diagram of what the circuit looks like. The question is would this circuit work? Also are 6millimeter IR emmiter with 960 millimeter wavelength work?

Question by planetroverrobo    |  last reply


5mm Round Red LED Lamp

5mm Round Red LED LampType: LED lamp Wavelength: 630-640nm Forward current (mA): 20 Forward voltage (V): 1.7-2.8 Luminous intensity (mcd): 5,000-8,000 Lens color: water clear Viewing angle: 15-degree Applications: for light, indicator and illumination

Topic by Ewan Chen  


Is it possible to make a garage opener remote from a tv remote or some other remote?

Is it possible to make a garage opener remote from a tv remote or some other remote which you can enter wavelengths into so you only need one remote for all your garages!!

Question by kjervar    |  last reply


LED Incapacitator

The LED IncapacitatorThis story has way too much instructables-appeal to go unnoticed. I like the following line particularly: "There's one wavelength that gets everybody," says Lieberman. "Vlad calls it the evil color."It all sounds a little too much like we will soon know one of these partners as Vlad the Incapacitator.

Topic by Sullen70    |  last reply


Quick cantenna question / idea

I've built a few cantenna's in the last few days and I've finally got one I'm really happy with, now I was wondering as radiowaves can't "see" holes that are significantly smaller than there wavelength (or so i understand) is there anything to stop me drilling say a 1/4" hole in the back, and making a sort of string cross-hairs on the front and sighting through the cantenna?

Topic by pyper    |  last reply


Questions about led

Hi! 1 :trying to find out if there are any  problem (caused by the red leds lower forward voltage) or not to drive blue and red leds with the same driver when connected in series.  2: if you drive  blue or  red led with lower capacity than rated (ex 2w instead of 3w) could that affect the wavelength for resp color could a red 660nm become a 630nm? the questions concern a growth lightsource thanks  

Topic by kristerh    |  last reply


Time-Lapse shows the beauty of the galaxy we live in.

I recently purchased a Canon EOS DSLR.This video made it painfully obvious what I need to be doing with it!This gorgeous video is a compilation of shots taken with a Canon EOS-5D every 20 seconds over about nine hours at a star party in Fort Davis, Texas. It's a humbling sight.The Canon was equipped with a fisheye lens (an EF 15mm f/2.8 lens) and powered with an external battery to capture all that goodness. The more interesting part is the replacement anti-alias filter the photographer, William Castleman, used: The Canon's stock AA filter blocks out certain red wavelengths to achieve a "more desirable" skin tone, but if it's replaced with a filter that lets those wavelengths in, you've got yourself a camera capable of shooting a galaxy, as seen here, even if we can't see it with the naked eye.Its also great to know about the filter, I am off to google more into that now!Check it out on VimeoVia Gizmodo

Topic by gmjhowe    |  last reply


Where can I get full UV LEDs? Answered

I need some full ultraviolet LEDs for a project. I've found some, but they don't output light completely in th UV range. These lights also put out visible violet light; I need them to give me invisible UV light. The wavelength that they put out needs to be around 300nm-350nm. Thanks.

Question by DIY Emilio    |  last reply


Can I measure everything?

Can something exist if has no mass or cannot be converted into mass? The mass of a photon is zero, yet how can a photon have energy but not have mass? If this is false, would that it be true that a box with and LED in it would have more mass when the LED is lit? But, are there other types of being aside from energy and mass? A concept perhaps. How would a concept be measured? The word apple is comprised of certain wavelengths that are detected by the human ear. In the human body as a system, the energy that my body requires to produce those wavelengths at "regular" amplitude (assuming there can be a standard amplitude) could be converted into mass. Would this allow me to measure the mass of the word apple in the system of my body? Right now I'm sure many of you are thinking that the word apple could be represented in many other ways such as writing. This is why I used the word 'system' when I referred to myself saying the word apple. Since there is no standard for the writing and speech of the word apple. Is everything comprised of something? Could that something be converted into mass? Can I measure anything?

Topic by astrozombies138  


i want to make my own led bikelight please help!? Answered

Here is the led info: Dominant wavelength max./ 10,000K Viewing angle 120° DC Forward current max. 350mA Peak pulse current - - 500mA Reverse voltage max. - - 5V Luminous flux typ. 56lm Forward voltage max. 4.0V i also want to make my own battery pack and my own light mount!

Question by thecookiemonster    |  last reply


Laser Diode Pinout. 4 pins??!!

Hi, I got a DVD Player at an auction, in fully working condition, for $10. So, since I already had one, I decided to remove the insides, and extract the laser diode within. I did so, expecting to have just a normal 50-200mw 3-pin red diode. Instead, I have a 4-pin diode, of unknown wavelength, color, and power. Would anyone happen to have a pinout for it? The pins are arranged as below in the picture.

Topic by metrogdor22    |  last reply


Lasers vs LEDs in the deep ultra violet spectrum, and focusing?

I am currently trying to research this topic as I am looking into building a stereolithograph 3D printer. I have been searching for some time now with not a whole lot of answers. This is not my area of expertise so I could use some input. I have found lasers in the range of 256nm wavelength but it is going to cost me an arm and a leg. Even at the price range the UV lasers are only outputting at most 1W of power. I have read that UV curing resin is most reactive in the range of 265nm and that is why I have been searching for something in that ballpark. I have found some companies that manufacture LED in that wavelength but then the problem is going to be trying to focus the light down to a fine enough point. I am trying to design a 3D printer that is in the high resolution range. So, my true question is. Does UV curing resin react best with the 265nm vs the 400nm range as I could just a blu-ray laser. If it is better at the 265nm range, could I possibly be able to focus enough light from a couple of 3W leds down to a small enough point to cure the resin where I want it to be. The other idea is taking a UV laser in the 400nm range and focusing the beam down to get me fine but quick set up time in the resin. Or possibly multiple Lasers

Question by ColtanA    |  last reply


Help with a blu-ray laser

I recently received a true 150mw 405nm burning laser. It came with the diode, a case, and a focus lenses so you can focus up to 30ft burnings. How can i power this safe without destroying it. Just connecting power to it, last i heard, is bad to do. What's the best way to connect this diode? Here's the specs: Diode Package Type: 5.6mm Max Output: ~150mW CW Max Current: ~110mA Lase Threshold: ~31mA Lase Voltage: ~4 volts Operating Voltage: ~5 volts Wavelength: ~407.5nm How to make a circuit to power this?

Topic by Killa-X    |  last reply


Colored Lights- How do colored led lights work and what do they emit?

I'm doing an experiment by growing plants under colored led lights, so do led lights emit specifically one color. For example does a red led light emit only wavelengths of light that are red and no others. I want to make sure that only one color of light is existent to get accurate results. I hope this makes sense. Also if you know of any 1-colored high watt led lights please link them to me.

Question by Potapids    |  last reply


LED Grow Lights

The Rundown... Ok, well, I was looking into writing an instructable (assuming that I can assemble it myself) on how to make your own LED grow light. I've got a few hours of research in to it and I was trying to figure out the most cost effective to way to build my own... ( I know it's normal to spend $300 on a grow light but I just can't justify it. :-/ ) Does anyone out there have any experience with different wavelengths or can anyone recommend locations/LEDs to buy? The little bit of information that I have as of right now is all single source so anyone with a bit of experience would be a lot of help. Thanks!

Topic by ZacDiggity    |  last reply


DIY WiFi Helical Antenna impedance Problems

First off, I live in the states, but I absolutely hate the imperial system of measurements. I will try to use the metric system as much as possible.I have been attempting to follow hanzablast's Helical WiFi Antenna, but have run into a few snags. I have most of the parts and have a few problems concerning it.1. Instead of a Type N connector my USB card has a RP-SMA connector. Do I have to do anything special (buy a special panel mount/ reverse the connections along the wire) because it has reverse polarity or does it not matter?Edit: I feel foolish, Doing a quick wiki search on Reverse Polarity SMA I found out what it means. Turns out WiFi companies reverse the gender of the inner pin in their connectors. So either I have to find a RP-SMA panel mount jack, or buy a RP-SMA Male to N Male Adapter and a N Female Panel Mount. The latter of the two seems more efficient.2. I understand that having too small of wire can have a detrimental effect on efficiency, but what about using a much larger wire (instead of AWG 16 gauge wire using AWG 4 gauge wire)?Edit: Answered By NachoMahma3. I am having trouble locating a SMA right angle 4-hole solder point panel jack mount other than in bulk buys. Does anyone know where to purchase one separately? Edit: Answered By NachoMahma, but has become a null point.4. I am having a problem with the impedance matching. I have seen several different ways to connect the antenna (142.68ohm impedance) to the SMA Jack (50ohm impedance). I've seen half and quarter circumference turns, quarter wavelengths turns, and triangular strips of copper. Which is best?Edit: I did the math and read my friend's ARRL handbook. Supposedly, a 1/4 wavelength turn of a metal strip with an impedance of 84.463 ohm is what I need. Using TraceSim I figured that I can use part of the copper plate with a size of 12.79033mm in width, 30.775mm long (1/4 a 2.437GHz wavelength), and 0.406mm (.016") thickness placed 8.03mm (1/4 distance between coils) above the reflector plate will give me the exact impedance I need.

Topic by AllAgainstPaul    |  last reply


I have 20 leds I want to hook in series. can someone tell me how to do it? Answered

Here are the specs of the bulbs. Parameter Typ Max Unit Luminous Intensity 4180min 10000 mcd Viewing Angle 24°~30° 23° Deg Forward Voltage 3.3- 3.6 V Reverse Voltage ~ ~ V Forward Current 20 mA Wavelength ----nm Operating Temperature Range -40°C to -80°C Storage Temperature Range -40°C to -80°C Lead Soldering Temperature(4mm from body) 260°C for 5 seconds Datasheet Download Color?

Question by sgtfarrar    |  last reply


Projector Light Bulbs are too expensive, Lets make an LED based one!

The idea is very simple PRojector Bulbs last average 2000 hours and cost $500 plus dlls. Lets make an LED based projector that will last at least 15 times that and cost under a hundred.With these: http://www.lumiledsfuture.com/products/line.cfm?lineId=2And this instructable:https://www.instructables.com/id/Power-LED_s---simplest-light-with-constant-current/Yes, light issues due to wavelength variations are expected as well as fan issues but all is needed is an old projector and +/- 10 high power LEDs and lots of instructa- bility.I am currently hunting for a damaged projector to experiment with...Please feel free to commentCheers!

Topic by dejabox    |  last reply


How to make doppler laser cooling? Answered

I've heard of a form of cooling done by lasers known as "doppler cooling" because it is based on the Doppler effect. I think this is neat and would like to try to make a laser cooling device. I can't seem to figure out how though. I did some google research and all I get is cooling options for lasers rather than cooling options from lasers. What wavelength would you need to do this? Is there a particular way to do this rather than just shining a laser continuously at an object needing cooling. Would this work through a translucent object? I appreciate any help or guidance you could offer.

Question by mykiscool    |  last reply


Fixing green laser lense

Last year I bought a 5mw eBay laser (green 532nm wavelength) and it had an adjustable focus. I scratched the lens and it never focus right so I took the lens off. Now I am interested in fixing it again and I don't know how to get/make/buy/obtain a new lens for the laser. It always said it was 5mw but I think it was more powerful because it could burn through bags, light leaves on fire, pop balloons, light matches at 6 inches. This is what the laser looked like. http://www.ebay.com/itm/High-Power-Military-Adjustable-Focus-Green-Laser-Pointer-Pen-5mw-Silver-/281269467436?pt=US_Laser_Pointers&hash;=item417cf7792c

Question by waterrocketexpert    |  last reply


I have 4 LED clusters, what voltage and amps should I give them? Answered

I've wired them up parallel with 9.6v and 800mA from an old transformer, but they seem really dim! What am I doing wrong?Here are the specs for each cluster.Technical Specification  Specifications (IF=200mA) Maximum luminous intensity:23000mcd Viewing angle:40 Typical forward voltage:9.6V (11.2V) Peak wavelength:660nm Maximum reverse current:100µA @ VR=18V Power dissipation:2.5W max. DC forward current:250mA max. Reverse voltage:5V max. Operating temperature range:-5C to 65C thanks for your help mark.

Question by Warne00    |  last reply


Idea for extended version of "Sun Jar"

After seeing the recent Sun Jar I'ble, I had an idea (not even concrete enought to be a Completable) for an interestingly extended version. There now exist LEDs for infrared, visible red, green, and blue, and near UV.It should be possible, with a mix of small low-voltage constant-current power supplies and pulse modulators, to construct a multiple-LED light source which roughly models what we perceive as the solar "spectrum." I don't mean formally reproducing the raw wavelength distribution, but rather the combination of intensities we see (or measure with a thermometer) in a prism- or grating-spread spectral display.Coupling such a circuit to a solar cell would allow you to build a "Sun Jar" which "collects sunlight" during the day and "releases sunlight" at night. As I said, just an idea...

Topic by kelseymh    |  last reply


mA on high intensity LED?

I bought a couple of red "Coast LED Lenser" LEDs from Frys (www.frys.com/product/4137893). They are in the standard 5mm package, but they give no forward voltage and the mA looks a bit high, being without a heatsink . If anyone can tell me if it looks correct and not a misprint, i would be very grateful, since coast doesn't have them on their website anymore. Oh yeah, while trying to light one I ran 8.5V@4.5A (PS2 adapter) accidentally (forgot the resistor) and it exploded loud pop instead of melting or burning out the junction like the 3mm LEDs from ebay, if that helps. The specs.   Intensity :                       10,000 mcd   Directivity:                      15* (degrees)   Operating Lifetime:      Up to 100,000 Hours   Wavelength:                  620nm   IF30:                               mA   IFP:                                 100 mA   VR:                                  5V   PD:                                  120 mW   Topr.:                              -30* to +100* (degrees) I'm guessing the forward voltage would be about 2.00V +/- .20V

Question by LuciferTengu    |  last reply


Finished building Low Level Laser Therapy Helmet using #38 3v and #69 5v diodes. The helmet will be used for hair loss prevention. Due to zero knowledge of circuitry, what's the safest and right way to power device? Answered

There are similar projects on this website but all using less diodes. I'm also not convinced that wiring all the diodes in a parallel circuit is the best route. If it is, then great and that will make my life easier.As you can see in the photos, I've soldered the diodes into bundles. However, each bundle either consists of only 5v or 3v diodes. If I need to desolder anything, so be it. Right now there are bundles of the following:5v = 20, 15, 22, 123v = 9, 9, 9, 11The diodes were purchased from Amazon and displayed the following specs:3V Output Power: 5mW Wavelength: 650nm Working Voltage: 3V Operating Current: less than 20 mA Laser Shape: DotWorking temperature: -10 degree~£«40 degree housing: CopperDimensions: 6.5 X 18 mm5V Output Power: 5mW Wavelength: 650nm Working Voltage: 5V Operating Current: less than 20 mA Laser Shape: DotWorking temperature: -10°C to +40°C Housing material: High quality Copper Dimensions: 6.5 x 18mmWire connection: Red wire connect to Positive, Blue wire connect to NegativeOther purchased materials2 x 4.8V 700 mAh Rechargeable Ni-Cd Battery Item Name: Ni-Cd Battery Dimension: 2.16 x 1.97 x 0.59 inches Plug: SM 2P Plug Charging time: About 2-3 hours Working time:About 20-30 mins5 x 4 Cell 4.8V AA Battery Holder W/ JR Style Connector ReceiverUltimate Goal: Simplify powering of helmet for 20-30 minutes / 3x a week by using on/off switch or plug.*This is my first time on this website and I apologize if I entered into the wrong category. THANK YOU in advance to anyone who helps. Greatly appreciated!!

Question by Randyroo1    |  last reply


LED Driver Help - 24 Leds, Red, 2.1-2.4 Drop, 700ma?

Hey everyone Been scratching my head for awhile now about this one. I believe I got the wrong drivers so I'm trying to figure out which one to get. I purchased these http://www.aliexpress.com/snapshot/266728353.html And I got this driver to run them http://www.aliexpress.com/snapshot/266728354.html But like I said, I'm running 24 in series not 18 and this drivers output is 680ma not 700ma I was going off the advice of a friend but I think he's wrong and I wasted my money (I can use them later though I'm sure) My question is Which LED Driver would be appropriate for these? If I increase the current (amps) would the wavelength change? It's just a tad lower then I wanted (more curious then anything) Can I alter the driver I got to accomidate the leds to save me money For future reference, how can I figure this out for myself Thanks guys, really hoping to hear back from you!

Question by tartooth    |  last reply


Seeing Auras & Ghosts

I have posted this on other forums without much response. Since some of the best minds use this site, I should get a lively response. Friday, on a TV show called 20/20, they interview some kids that said they see auras and spirits. Do any of you know people who can do that? I have tried to see or photograph auras without success. It seems that these things may be visible either in the ultraviolet or far infrared and require someone with eyes that are more sensitive to these wavelengths. Young kids would be better at that. Infrared and ultraviolet light (UV) are in our environment, even though we can't see it. You would expect that different people would look different under UV, just as they do under visible light. Additionally, some things show fluorescence under UV. Perhaps auras are differing fluorescence by individuals as seen by those with extended visual response. It might be interesting to look at various people under just UV or just infrared (perhaps using night goggles) and note the observations. It would be interesting to have someone view auras through various filters to see how the auras change. Are auras affected by magnetic fields? Would smoke in the air have an effect? Does the aura look better with a dark background? Does getting drunk help? Ghosts are probably more difficult. It is to be expected that God doesn't want us asking them sensitive questions (like "Where's Heaven?"). ~Bob~

Topic by ShutterBugger    |  last reply


How can I get a suitable voltage from a 5V power supply? Answered

Hi all, I've got a laser diode, with the following specifications: "Wavelength:808nm Power Output CW 500mW Working Current: I<350mA Working Voltage: 2.2V" And a laser diode driver: "1. Constant current Stable voltage IC circuit, laser diode can be better protected without being damaged 2.Constant current output , Can be adjusted(0~580mA) 3.DC supply voltage input 3.0~4.2V. 4.Suitable for 808nm 100mw~500mW laser diode." The combination of these two things will be switched on and off by an Arduino (Probably using a relay, as the driver board has a switch connection) - This may change but I don't imagine this will matter. ---------------- I noticed that the 'DC supply voltage input' says 3.0-4.2V . My power supply will be 5V (I don't imagine that Amps matter but if they do, it has a max output of 34A). What would the best/safest way to do this be? I don't want to burn out my laser because they're comparatively expensive, and I'd like it to be able to run relatively continuously (Probably multiple-minute continuous usage) (For those of you wondering, I'm one of the many people making a laser engraver/cutter from scratch)

Question by jonrb    |  last reply


How to get the best range out of an IR LED? Answered

Hello, I'm using my Arduino as a universal remote and I've got everything working, but my IR LED isn't really strong.  I've read around the internet and all I've found are people using an IR LED with either a 33 Ohm or 100 Ohm resistor in front of it. Currently I'm using this RadioShack High-Output Infrared LED http://www.radioshack.com/product/index.jsp?productId=2062565 [Radiant Power Output = 16mW min  Forward Voltage = 1.2V  Forward Current = 100mA  Wavelength = 940nm] with a 100 Ohm resistor in front of it and only get a foot or two of range.  I'd really like to get out to about 20 feet but I could make due at 15/16 feet.  So I got nose-y and opened up my TV remote... it's all surface mount, but as best I can figure it the signal leaves an IC, goes through a 100 Ohm resistor and then goes into a transistor (labeled 2T) before heading out to the IR LED.  The third pin from the transistor snakes around to a bunch of other parts and I lost.  So I was wondering what to do to increase the range of my IR LED... change the resistor?  Power it via a transistor?  If I can use a transistor does anybody know how to wire it up? Any help is much appreciated. Nick

Question by Schmidtn    |  last reply


I patented a New LED great for home projects and display cases

I have spent three years doing this but here it is. This is a new LED and I actually patented it. Its a screw in unit that has a chip mounted directly onto a solid brass core that takes heat away far better than any circuit board. In addition it screws into any m10x1.5 hole, if you use a flat plate on the front a small insulator and a heatsink or metal on the back with the M10 thread all you need do is make an electrical connection to the plates and you can screw any colour you want into the heatsink. It comes in every wavelength from 380 (uv right up to IR at 1040nm) Ill be adding pics shortly of acrylic displays the 180 degree one is absolutely perfect for these i use frost spray on edges i want to illuminate and leave clear other bits the effect is amazing even masking a flat acrylic and putting two tone pictures using the spray is awsome. iv also designed an off the shelf PCB up to 60watts it drives any series parallel circuit, all you do is program it with the wattage of the whole array. If you program say 15watts in an array with several LED's it powers the array with the exact forward voltage required and alters realtime so the light output is near constant. Also have a patent pending on this as well. I have lots of time and plenty of these available if anyone is interested I am now running a small business based around it and have done some really nice hand crafted kit. More pics to follow all questions welcome Thanks all

Topic by L.E.D Guy    |  last reply