How a passive radiator works ?

Hi, I already made a topic for a speaker so everything for now is going forward, but now there is a thing that I don't understand. How a passive radiator works ? I bought these : http://www.ebay.com/itm/2pcs-40-70mm-Bass-Film-4070-Bass-passive-board-Bass-diaphragm/151785155803?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D37115%26meid%3D601cf622b593403580c218ae762baf34%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D151785222974 But I don't know how I have to power them and connect them to my full range/tweeters speakers with my amplifier.

Question by EgeK2   |  last reply


What could be inside of this? It is something for removing earth's radiation? Answered

What can be inside of this (Attachment) ? It should be a device you put under your bed to neutralize health effects of Hartman and Curry grids - Earth radiation. I am guessing a simple coil, but what is happening if you connect it to the power outlet's ground? What do you think about it? Is this bogus device, and would there be a way to neutralize those radiations? (I do not have this thing, I just want to prevent my father from wasting $50... by the way there are no possible returns)

Question by jakovn   |  last reply


CFL's putting out too much UV radiation?

Our local (I think) news service has done a story about CFL's emitting too much UV radiation, You can view it here.Would you rather sit under an incandescent light or a CFL for a extended period of time?Do you think they should have warning labels on them?Do you have any other opinions on CFL's and energy saving globes?Or do you think this is all just a way to get more people to but the old incandescent bulbs?

Topic by thermoelectric   |  last reply


How can I tell if my watch parts are radioactive? (for cheap... can I use unexposed film?)? Answered

I heard that sometimes you can't tell if the antique watch parts you are decorating Steampunk items with have been in contact with radium paint.

Question by Nickelplate   |  last reply


Using peltier to cool my radiator?

I have this idea and wonder if it is possible and feasible. Stick a peltier to my car radiator to generate electricity and store the electrical and then using the same peltier to cool my radiator?

Question by doshur   |  last reply


Watercooling a PC with a central heating radiator?

So I'm completely new to water cooling, I own a closed loop cooler and I know the names of the water cooling parts and assembly, but I have no real experience. I presume it's possible to use a normal radiator as a passive radiator in a loop, but I've got a couple of questions. First, do I have to be worried about what the radiator and waterblocks are made of, are the metals important? Second, will I need a significantly more powerful pump than the standard D5? Thanks! P.S. the rad I had in mind is this http://www.screwfix.com/p/flomasta-type-11-single-panel-single-convector-radiator-white-300-x-800mm/38602   It's rated for 1505 BTU/hour, which equates to 441W, which is in theory plenty my PC (4670K, HD7850 which I'll probably upgrade in the near future) The reason for using this kind of radiator is because they're far cheaper and passive, although I suppose the increase in pump power may negate quietness of no fans. It's also more fun ;)

Question by CustardInc   |  last reply


lighting an led using mobile phone radiation.

When i went to science fair, i happened to c a simple circuit with an led. they brought a cell phone near to the circuit.. when we call or send msg to that mobile phone, the led started to glow. can anyone help me in building such a circuit? a simple one is enough.. thanx in advance.

Question by allsparkunleashed   |  last reply


what's the process involve in making radiator coolant? Answered

I am interested in the process of making radiator coolant.What are the chemicals used in the process,the measurement etc.

Question by islandhopper   |  last reply


Use old car radiators for solar collector?

I have salvaged 2 car radiators that are old yet not leaky. I want to use them for active closed loop solar collectors. Any advice?

Question by    |  last reply


Can convection be used to drive a passive dehumidifier?

Ok, I have a couple of radiators and a greenhouse that is too humid. In winterr can convection drive fluid from a radiator mounted low in the warm greenhouse to a second radiator mounted outside in the cold and then back to create a chilled metal radiator that will have water condense on it and drip into the soil.

Topic by drewgrey   |  last reply



why do cost of production of radiator cap differ at different places?

Why do cost of production of radiator cap differ at different places? example at pune and mumbai...

Question by pallavishivdas   |  last reply


My Project For The New Year

I think I've found a nice big project to undertake for 2009. I want to build a homebrew X-ray machine. I've done a little bit of research and found that United Nuclear sells X-ray tubes along with radiation safety equipment. I think I could make the other components needed (high voltage supply) by myself. Does anyone have any ideas or thoughts on this project?

Topic by Gjdj3   |  last reply


How do you change radiator in 98 Achieva with pictures if you have them?

My husband is replacing the radiator in our 1998 Achieva, but he is having trouble removing it.  Can you give instructions with pictures if possible so he can see what he is doing wrong.  Thank you.

Question by teressa55   |  last reply


How To Repair A Car Radiator Leak In The Plastic Area? ? ? ? ?

I have a radiator leak that I want to repair instead of replacing the whole radiator. I tried a couple of 2 parts epoxy glues and it won't hold for long. I think the heat just makes it weak. They are small leaks(2) on top of the plastic area. I was thinking maybe trying some fiberglass resin and cloth since I have some leftover from my fibeglass speaker box I've done a while back but not sure if I should go that way. Anyone knows of another way? Anyone had this problem and got a fix? or if there's a website where I can get the top piece to replace it myself please post a link. It's a 2000 dodge neon. Thanks.

Question by PitStoP   |  last reply


Use car radiators for solar collectors. Any advice?

I have salvaged 2 car radiators, they aren't leaky. I want to use them for active closed loop solar collectors. Any advice? My current plan is to put them on the roof (in a hot box), then plumb them into an old water heater in the attic. My hope is they can recirculate glycol in a closed loop, convection only, but I may need to install a thermostat and pump. Anyone have experience in this? I want to dump the heat to my 2 water heaters in the basement (they are plumbed in tandem, so I can use the 1st tank for solar boost and 2nd tank for final temperature control). Heat exchangers: either the Butler Solar Wand, or Brazed Plate Heat Exchanger (single or parallel). Differential Temperature Controller from www.jc-solarhomes.com. Any advice or suggestions hugely welcome. thanks in advance, Chris

Question by    |  last reply


how do i connect thermo switch with ele. radiator?

First things first notice: Iam in Europe so it's probably a bit different than in USA. I have electric radiator in my room. i bought thermo switch but i don't know how to connect it between the socket and the radiator. I must mention that the radiator had already same thermo switch before but it broke down after 5 years and I didn't write notes how it was connected. I already blown 4 fuses during the attempt. The wire has blue (P?), brown (N?) and yellow/ green (earth) wires. In the switch there's sheme sticker -> www.shrani.si/f/C/Nr/42sKtVVC/thermo.png. notice i have a plug and wire from the radiator both with mentioned wires. I checked blue wire and it's live (P??). Green-yellow wire is earth.. iam sure. so how do i connect the plug and the radiator?? 

Question by Karletto555   |  last reply


I want to manufacture radiator coolant for vehicles. Pleae tell me the process.

In ur ans in yr 2010 u ve mentioned about the dye.. what kind of dye is requierd ?? 

Question by arcbits88   |  last reply


Thermal Electric generation using peltier modules and a household plumbed radiator?

My idea was being energy conscious of some how incorporating thermal heat from the heating system of my house to power LED Lights in the rooms where there is radiators. I need to find a way to incorporate a make shift kit using peltier modules heat from the radiators and a natural way to cool in a bid to reduce the electric during the winter months. Advice is welcomed and opinions also taken onboard as regards to its productivity and if it will be able to do its designed task. Thanks.

Question by AlecW   |  last reply


Can I substitute a vertical antenna for a dipole? (Also, how do I protect it from lightning?)

I have a project that requires a 87 foot long dipole antenna. Would it be possible to use a 44 foot long quarter-wave vertical antenna in place of it, to save space? And is there any DIY way to protect the antenna from lightning? How well do they work compared to store-bought lightning arrests?

Question by ElectricUmbrella   |  last reply


room thermostat

First things first notice: Iam in Europe so it's probably a bit different than in USA. I have electric radiator in my room. i bought thermo switch but i don't know how to connect it between the socket and the radiator. I must mention that the radiator had already same thermo switch before but it broke down after 5 years and I didn't write notes how it was connected. I already blown 4 fuses during the attempt. The wire has three wires: blue ("live"), brown and yellow/ green ("earth"). In the switch there's sheme sticker -> www.shrani.si/f/C/Nr/42sKtVVC/thermo.png . so how do i connect the plug and the radiator??  www.imit.it/dati/schedaArticolo.php

Topic by Karletto555   |  last reply


peltier device air con

Hey guys I am working on a project, my first, and am wondering if any one is willing to offer advice. the simple setup uses a swamp cooler to blow cold air over a radiator. the radiator cools down water that is connected to a peltier.if my theory is half accurate (which at best it is) I should be able to make the peltier quite a few degrees below the ambient temperature.

Topic by plucas1   |  last reply


Awesome modifications that would allow a person with severe electromagnetic radiation sensitivity to use a computer?

Here's a challenge: My friend cannot be in the same room as anything emitting electromagnetic radiation, so no computer or phone, but she longs to be in touch with people. She's now limited in contact to her husband and people who come to visit, but is about to move away from the city where we live to a small town with cleaner air (she's also struggling with multiple chemical sensitivity), so will be moving 2.5 hours away from most of her friends. I can imagine some awesome solution that would transition from mechanical technology to digital signals (ie. typewriter keyboard connected to computer in the other room), but I'm not the hacker to do it. Is there anything existing out there? This seems like it would be right up the steampunk folks' alley. Any good ideas? Sources for solutions? Any thoughts that anybody has would be greatly appreciated, and probably put to use. Figuring this out will add significantly to my friend's quality of life...!

Question by    |  last reply


Awesome modifications that would allow a person with severe electromagnetic radiation sensitivity to use a computer?

This is more of a challenge than a question: ! My friend cannot be in the same room as anything emitting electromagnetic radiation -- no computer or phone -- but she longs to be in touch with people. She's now limited in contact to her husband and people who come to visit, but is about to move away from the city where we live to a small town with cleaner air (she's also struggling with multiple chemical sensitivity), so will be moving 2.5 hours away from most of her friends. I can imagine some awesome solution that would transition from mechanical technology to digital signals (ie. typewriter keyboard connected to computer in the other room), but I'm not the hacker to do it. Is there anything existing out there? This seems like it would be right up the steampunk folks' alley. Any good ideas? Sources for solutions? Any thoughts that you might offer will be greatly appreciated, and probably put to use. Figuring this out will add significantly to my friend's quality of life...!

Question by    |  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 


Can someone here point me to some bacteria that glow when stimulated with IR light, or any kind of radiation? Answered

The reason I need to know is I think it would be a real cheap alternative to conventional night-vision goggles. I have seen projects to that end that employ digital cameras with the IR filters left off the lens, but I am concerned that those projects have a latency that would make it difficult to function in real time. I would also be grateful if someone could inform me of a material that would allow IR radiation to pass through, but block visible light. 100 internets to the provider of thebest answer.

Question by nruegs   |  last reply


How do I split a circle in Illustrator?

I'm new to Ai and I am trying to make a "radiation hazard" sign, but I have been unable to split a circle into individual segments that I can color. Any help is appreciated

Question by Data643   |  last reply


How can I block wifi signals? Answered

I'm doing a science experiment to see what wifi does to health, so I need to block it. I want to make a box holding cell cultures or something to see what happens. 

Question by ANDY!   |  last reply


House hold heating? Answered

Like most UK houses my thermostat is in the coldest part of the house - The entrance hall. Although I have recently fitted thermostatic valves fitted to all radiators I can't help but feel the heating would be more effective if I simply controlled the temperature in the room we spend most time in during the evening- The lounge. I guess this would mean the rest of the house would be cooler than at present but that isn't really a problems for us. Is there any reason, anyone knows, not to do this? Has anyone gone down the smart thermostat route? https://nest.com/uk/thermostat/life-with-nest-thermostat/ New high efficiency condensing boiler Thermostatic radiator valves through the house High level of insulation to walls and roof. Double glazing all round in PVC frames.

Question by rickharris   |  last reply


need replacement for Koolatron heat exchanger Answered

My refrigerator died. the heat exchanger won't test. It's 3.75 x 4 inches without the radiator fins. 40 watts DC. Apparently Koolatron doesn't carry them, planned obsolescence is unethical (unless you're a shareholder). Where do replacements come from?

Question by Jakey2   |  last reply


Is there a way to make an old pc power supply power over 16 fans?

I have 4 radiators on my water cooling circuit and each one has 4 fans...16 fans total but i have no feasible way to power all of them... any ideas on how to make an old 230 W pc power supply power the fans?

Question by Mighty Mackinac   |  last reply


Selectively magnetized (hemi)sphere

Hi everybody! I'm looking for a way to construct a hemisphere, - maybe 1.5" to 2" in diameter - ideally with no moving parts - where any of a number of areas on the surface could be magnetized at will I thought of having an array of tiny electromagnets starting from middle and radiating to under the surface, but frankly, that would take a long time, and I figure there would be insulation issues. Any suggestions?

Topic by drmab   |  last reply


Does a florescent black light carry any health risks greater than that of a regular florescent bulb? Answered

Does it generate a higher level of UV radiation than a regular florescent lamp  or just "filter out" visible light with colored glass like the incandescent black lights? Should I worry about extended exposure to the skin or eyes? Thanks.

Question by C2H6   |  last reply


Are my flyback projects dangerous? (x-ray) Answered

Hello, I was wondering if any dangerous x-rays or other caustic things like ozone are created when I'm testing my flyback transformers. How much ozone and how much x-rays is dangerous to humans? could long-term use of flybacks create radiation poisoning? I'm actually a little worried :/

Question by DELETED_Electorials   |  last reply


Peltier dehumidifier

I hope someone with a technical background can help me with this... I am trying to make an DIY dehumidifier. The goal is to lower the humidity of my room during the summer months (humidity is around 70% at 25C) to less than 50, preferrable 30%. I have the following setup in mind: To achieve condensation I want to use a peltier that will lower the temperature of an radiator. The condensed water will be gathered in a (plastic) box. This water will then be used to cool the hot side of the peltier, using a water block and a waterpump that was left over after using watercooling on my PC. The image depicts an simple graphic of the setup. However, I have the following questions to be answered: - How cold (relative to the ambient temperature) would the cold-side radiator have to be to get optimal condensation - How much watts of cooling power would the peltier need in order to achieve the needed temperature difference - If i lower the cold side temperature with 20C, how much heat would be generated on the hot side? (my gues: 20C, but im no genius ;) ) Thanks in advance!

Topic by pelzinga   |  last reply


A lot of houses feature falling waterfalls. Has anyone ever used one for a water cooling system for a PC?

Http://www.discountfountains.com/product.php?productid=84&cat;=6&page;=1 is an example of such a waterfall. I was thinking that making one with tubing running accross the surface of the water flow so that the falling water cool the tubes, and the water in these tubes would be used to cool the PC. It would be a aesthetic way to make a radiator that is fanless, functional and pleasing to the eye.

Question by anaipatel   |  last reply


I would like 5 environmental sensors linked to an Arduino then to my smart phone or an Ipad. Is this possible?

My idea is to have a radiation detector, emf detector, static ion detector, radio wave detector, and temperature gauge going to an Arduino, and it reading all 5 detectors at the same time, giving simultaneous readings of the immediate environment.  The device would give readouts in real time onto my smart phone or an IPAD, recording the data for later reference

Question by ghostman1029   |  last reply


so I want to heat/bend 12 ft long lumber. Is there any safe way to cut a hole in my microwave and run it through?

so I want to heat/bend 12 ft long lumber. It only takes about 20 seconds in a microwave. So I'm handy with the grinder but know nothing about microwave radiation, start it up and get far, far away. Or .... Is there any kind of large/long microwave yooz guyz  know of?

Question by jimboa2020red   |  last reply


POWERING ATOMIC REACTOR CLOCKS:LASER SOLAR PANELS:USE LASER LIGHT NOT SUN

USING LASER SOLAR PANELS(NOT SUN LIGHT LASER LIGHT) INSIDE ATOMIC REACTOR COULD MAKE REACTOR FIRE SAFETY WITH USING FIBER OPTICS THAT HOLD LIGHT ENERGY TO TRANSFER ENERGY IN AND OUT OF ANY ATOMIC CLOCK: FIBER OPTICS CAN MOVE LIGHT THROUGH ANY BEND OR SMALL TO REACH PLACES AND THEN TRANSFER ITS LIGHT TO ENERGY WITH THE FOLLOWING IDEA. BY SHINING LASERS ON SOLAR PANELS THAT ARE INSIDE ATOMIC AREA DEVICES TO GIVE THE PANELS ELECTRICITY FOR REACTOR CLOCK AND REPLACING ALL DANGEROUS WIRES THAT SEND ELECTRICITY TO ATOMIC PARTS OF NUCLEAR PLANT. WITH NEW FIBEROPTIC WIRES TO SEND PHOTOVOLTAIC WIRES THAT SEND ELECTRICITY WITH LASER LIGHT. VERY SAFE COMPARED TO WIRES THAT WHEN CUT MAKE SPARKS OR FIRE. FIBEROPTIC WIRES ARE SAFE IF CUT ONLY NON DANGEROUS LIGHT WILL BE LOST. AND COULD REDUCE RADIATION FROM CROSSTALK THAT COME FROM REGULAR COPPER WIRES. One more idea can you charge a solar panel battery recharger by shinning laser beam on the solar panel cells in places were there is no sun light using laser light which can charge a device from a range of up to a football field if needed. This might be used in caves or evenin drilling for in off shore oil rigs were there really is no light in deeper water. And all other light sources of light would be distortedby reflection from the water. Only a laser beam could recharge aelectronic device by using photovoltaic in deep water where sundon't shine and only a laser will not have all of its light reflectedbecause of the water's reflection property, you would only be able touse laser light properties has less water reflection than normal light. BY HUME SCIENCE INTERNSHIP FIBER OPTICS TO SEND LIGHT INSIDE ANY TYPE OF ATOMIC AREA AND CONVERT IT ONCE INSIDE CORE INTO ELECTRIC POWER AND SAFELY DECREASING RADIATION PROBLEMS. THIS IS GOOD BECAUSE LESS COPPER WIRES ARE NEEDED.(ONLY LIGHT WOULD BE TRANSFERED IN CASE OF WIRE IS CUT ONLY LIGHT WILL ESCAPE MUCH LESS DANGER. USING FIBER OPTICS TO SEND LIGHT ENERGY ONTO SOLAR CELLS INSIDE REACTOR/THIS IS A GOOD SAFETY TOOL BECAUSE IF FIBER OPTICS ARE CUT ONLY LIGHT WILL BE EXPOSED AND NOT DANGEROUS ELECTRICITY WHICH WILL CAUSE RADIATION PROBLEMS. TO SEND ELECTRICITY INSIDE THROUGH OUT REACTOR//: INSIDE ATOMIC RADIATION AREAS. THERE ARE NO NEED FOR ELECTRIC WIRES. IF ELECTRICITY IS MADE INSIDE REACTOR CORE, BY SHINING INFARED ON SOLAR CELLS OBJECT NOT SUN LIGHT ONLY INFARED LIGHT ON THEM PANELS. THIS LIGHT HAS TO BE LASER OR INFARED BECAUSE IT CAN BE CONTROLLED USING INFARED LIGHT THIS ALLOWS IT TO BE MORE CENTERED THAN SUN LIGHT CAN. REDUCING ATOMIC RADIATION IN ATOMIC REACTOR CLOCKS. AND NOT USING WIRES. A ATOMIC REACTORS CORE CLOCK HAS TO GET ELECTRICITY. THIS CAN BE DONE WITH SOLAR PANEL CELLS PLACED AND CONNECTED TO THE CORE'S CLOCK. THEN BY SHINING LASER LIGHT OR INFARED LIGHT ON SOLAR PANELS THAT ARE INSIDE THE CORE CAN GIVE AND GET THE LIGHT ENERGY POWER IT NEEDS TO RUN TRANSISTERS AND COMPUTER CHIPS. FROM SOLAR PANELS THAT ARE CONNECTED TO THE CLOCK INSIDE THE CORE. AND ARE BEING GENERATED BY CONTROLLED LASERS THAT ARE ALLOWED TO BE AT VARIABLE DISTANCES. CAN ELECTRICAL ENERGY BE TRANSPORTED BY A LASER. SURE JUST SHINE IT ON THE SOLAR PANEL AT NIGHT AND YOU WILL GET A LITTLE ENERGY, SURE IT WORKS. CAN A ATOMIC REACTOR GET ITS ENERGY VIA LASER LIGHT INSTEAD OF WIRES DOING THE TRICK. NOW WITH LASER OR FIBER OPTICS. WIRELESS ELECTRICITY CAN BE SENT WITHOUT WIRES.ELECTRICAL WIRES COULD BE THE PRODUCER OF STATIC RADIATION. WIRES DO SEND ENERGY INSIDE THE CORE AND GIVES ENERGY FOR THE CORE'S REACTOR. CAN THIS IS ALL DONE WITH NO WIRES INSIDE THE CORE; IF WE ALLOW ENERGY TO BE SENT VIA LASER LIGHT TO A CONVERTER OF SOLAR PANELS COULD CREATE ELECTRICITY IF THOSE SOLAR PANELS WERE DIRECTLY SHINED ON TO BY LASERS. A GREAT DEAL OF WIRES COULD NOT BE NEEDED. SENDING POWER TO CORES WATCH OR CIRCUITS IS POSSIBLE. BY SHINING A CONTROLLED LASER ON THE INSIDE OF A CORE'S SOLAR PANEL CAN BE ACHIEVED BY FEEDING THE SOLAR CELLS INSIDE THE REACTOR WITH LASER PHOTO ENERGY LASERS WOULD SIMPLY SHINE ON INTERIOR REACTOR SOLAR CELL COMPONENTS. ONLY DIFFERENCE IS INSTEAD OF SUN LIGHT CREATING THE ENERGY IT WILL BE A HIGH POWERED LASER SHINING ON THE PANEL SOLAR CELLS. USE LASER LIGHT WHICH IS MORE DIRECT AND IS MORE FOCUSED OVER A LONG DISTANCE. LESS RADIATION AND LESS WIRE WASTE IS THE FINAL RESULT. HAVE A GOOD CLEAN DAY. THIS IS A NEW FORM OF TRANSFERING ELECTRICITY TO EXTERNAL LOCATION. USING FIBER OPTIC LIGHT AND SENDING IT AND THEN RECIEVING IT ACROSS A DISTANCE WITHOUT WIRES. THIS SEEMS SAFER TO ME BY USING THIS METHOD. REMEMBER THIS; WE ARE NOT USING SUN LIGHT IN ANY OF THESE METHODS ONLY LASERS OR FIBER OPTICS. THIS IS INFORMATION FROM A SCHOOL PROJECT OF MINE AND IF YOU CAN GIVE MORE ON THIS SUBJECT PLEASE DO. PLACING SOLAR PANELS INSIDE BUILDINGS NOT JUST OUTSIDE, AND CAPTURING OFFICE LIGHT 24 HRS MORE PROJECTS THAT I WOULD LIKE TO EXPERIMENT A INTERNSHIP WITH! PLACING SOLAR PANELS INSIDE BUILDINGS NOT JUST OUTSIDE, AND CAPTURING OFFICE LIGHT 24 HRS

Topic by humexavier   |  last reply


Reducing the influence of low temperature objects on PIR sensors?

​Hello, can anybody please help me with this? I was wondering if there was some sort of filter/material that I could place in front of a pir module, that would filter out any low temperature objects and only allow high amounts of infrared radiation to pass through and trigger the sensor (body heat). I plan to mount the sensor on a rotating turret, and when it spins I don't want the sensors to be triggered by the moving background (walls, bookshelves, etc.) thanks.

Question by SentryGunner   |  last reply


An interesting dilemma?

Ok, so this is actually pretty interesting. We have a Netflix enabled Blu-Ray player. It connects to our wifi to run the streaming... But we have noticed something weird.... Every time a movie is playing, and the microwave runs- the movie abruptly stops and the player says "The network appears to be down. Retry?". This has happened consistently 4-5 times. So my question- is the microwave radiation enough to cause bumps and glitches in the network? The network is run off a Apple wifi routers, and it should be wireless N (5ghz) Any ideas if this could happen? 

Question by astroboy907 


Help with photodiode?

Hii i am working on a circuit where i want to use photo diode as a switch.. that is when infra red radiation falls on the photo diode, it will allow the current to flow through the remaining circuit. but when i did the circuit, there was a small problem. even if ir led is not used, small current is passing through the remaining circuit. how can i stop this. how can i make it in such a way that no current will flow through the photo diode unless ir rays are allowed to fall on the photo diode... thanks in advance..

Question by allsparkunleashed   |  last reply


how can i tune a received ightwave like a guitar's strings and what is the energy required per kHz?

                                                                     Is a light wave like a guitar string?  Can i take a received electro magnetic wave and tune it? For instance, can I take white light into a device and change the waves properties so that it comes out as red light, or microwave radiation? The applications could be staggerring. If, for instance, I could take incoming sunlight and tune the wave so that the output was alternating current electricity. This would seem to me to be a far better way to harness the enormous energy contained in a lightwave.

Question by tswartwood   |  last reply


GPS Repeater from a Hacked Wirelss Router?

Hi all. I'm building a GPS Repeater. I'm wondering if any one has ever tried to use the LNA on the Xmit side of a wireless router to amplify and re-radiate a GPS signal? I'm still in the research stage, but I'm thinking I can take the signal from a active GPS USB patch antenna, tie it into the LNA input on the RX side of a wireless router (hack all signals in the router- we are just interested in the power and signal input). Schematics to a router would be great. I have 10+ years in RF, so I know that the Xmit on a router is so not 1.5GHZ range like GPS. A few mods to some componets can ceratinly help turn the center freq of the Xmit. on the router.   What are your thoughts?

Topic by chris23892   |  last reply


How to make a simple wireless digital communication circuit?

Hey, i want to make a simple wireless digital communication circuit. This is not exactly what i'm going to do, but this is the easiest way to explain it: watch the image below. What should i build inside "box ?(1)" and " box ?(2)", to make the 2 LEDs turn on when i push the button? The first circuit should be like a transmitter and the seconds one a receiver, but i just don't have any idea how to make this simple circuit. I don't really know what frequency it should be at.. What's the easiest to make and works for the longest distance without problems with background radiation? (I'm sorry if this is a stupid question but i really a noob in hardware development... :p ) Thanks for helping! Evert

Question by eds1999   |  last reply


Homebrew heaters using resistors?

Hello, First time poster! :) I've been reading up on some projects on this site centered around small homebrew heaters. One I came across I want to adapt is using two resistors and usb port power to make a small coffee mug heater. I'm kind of a novice at electronics, but I'd like to know how to design such a heater with safety and functionality in mind. I also want to control this heater via arduino if I can get a prototype together. Some questions I have: Where to get and what kind of resistors for heaters? How do I figure out what resistors to use based on power. e.g. 12v or USB power? What's a good thing to "encase" the resistors with that will withstand heat? I have thought about using radiator repair epoxy. Thanks for any help!

Topic by Sylvester2009   |  last reply


does anyone know where i can get any of the below materials for cheaper than normal???? Answered

-A vacuum chamber, preferably in a spherical shape -A roughing vacuum pump capable of reaching at least 75 microns vacuum -A secondary high vacuum pump, either a turbo pump or oil diffusion pump -A high voltage supply, preferably capable of at least 40kv 10ma - Must be negative polarity -A high voltage divider probe for use with a digital multimeter -A thermocouple or baratron (of appropriate scale) vacuum gauge -A neutron radiation detector, either a proportional He-3 or BF3 tube with counting instrumentation, or a bubble dosimeter -A Geiger counter, preferably a scintillator type, for x-ray detection and safety -Deuterium gas  -A large ballast resistor in the range of 50-100k and at least a foot long -A camera and TV display for viewing  -Lead shielding

Question by garagegenius   |  last reply


How can I purify mineral oil?

My early experiments with oil-cooling my PC lead to some chemical *discoveries* The first was mineral oil will dissolve latex rubber.  I was using surgical tubing to pump the oil to the radiator and after a day the tubes had softened and swollen so much they wouldn't stay attached to the pump.  That and the oil turned an ugly yellow. (* the second was warm oil reacts with PVC, and causes the insulation on usb cables to become brittle) I'm working on the next gen of the project and I'd like to clean up the oil, but I can't quite google my way to a solution. I have filtered the oil (removed all the bugs) though a coffee filter, and a couple of paint filters, I don't have any reason to believe the rubber is suspended and filterable, but I could be wrong. Any chemists out there know what I can do?

Question by Malkaris   |  last reply


Solar Concentration?

I wonder if anyone has tried this, using either a solar cell, or joule thief powered LED in something like a torch head fitment  with a solar cell capping the end of the torch head such that the maximum amount of vsible light is falling on the solar collector and none is going any where else. Although direct sunlight may be ok to power a PV, because of local weather it could still be described as diffuse and tricky to get a constant intensity of light where it is needed. If it were possible get a gain in efficiency this way it also could mean that you are not constrained by the amount of area you need to lay out panels to catch sunlight, the collectorsand lights could be stacked vertically in enclosed units.Apparently PV'sare most efficient in the visible light spectrum which reduces concerns of radiation (UV or IR) If efficiency and power could be increased in this way small units could be joined in series or in gradually  increasing size to power requirements.

Question by Nowandthen   |  last reply