Topics


How can my soundbar be rated at 300W-peak/150W-RMS, amp IC only goes 78W, 5 drivers total 60W?!?

Pyle PSBV200BT. Audio amp IC is STA540. Speakers and marked ratings: Two tweeters @ 10W, 4 Ohm; two midrange @ 5W , 8 Ohm; and one sub-woofer @ 30W, 8 Ohms. PS is 18VAC@2.5A. Am I missing something. The numbers seem so wrong that I must be overlooking something significant, not just overseas marketing greed. The Pyle sounds ok, but my 17-year-old 100W Creative 5.1 PC speakers blow it away.

Question by MarioL111  


Can I make line follower robot on white line and can you help for coding for this

I want to make line follower robot on white line i need program for that so can you help for the coding to made that robot.?

Question by Pranali parange    |  last reply


Blue-ish tint to my projector?

I recently bought a digital lcd data projector from garage sale , i saw the projected image before buying and was happy with it , but alas once getting it home and setting it up the image now has a blue tint it. the projector model is,  Sony VPL-351QM  lcd data projector . i think it was made in about 1994 , and it weighs about 25 kgs, to be honest when i saw it i thought it was some sort of old digital cinema projector, like they use for the Ad's before a film. any help would be much appreciated.

Question by jesusofnazereth    |  last reply


Choosing a transistor (NPN)? Answered

Hey Guys, Recently I was ordering electrical components online and when I reached transistors I couldn't choose any. I was wondering that can I order any transistor or will it ave to be specific one? I need one for projects like wireless induction, laser tripwires etc. I would really appreciate it if you could help. Thanks in advance -Prickly Potato

Question by The Prickly Potato    |  last reply


Removing Broken M2 Tap from Anodised Aluminium 2014.

Hello Everyone,As you might have read, I have a Milled Aluminium 2014 Block which is Anodized with Black color, Today when I was tapping the holes of it, the M2 Tap broke and got stuck inside that hole, there is no portion of it outside the hole, so I can't unscrew it and pull it out.I saw a few videos on youtube on how to use alum water, or electrolysis(with 10% dil H2SO4) to dissolve or chemically remove the Tap bit from the hole, But my question is is it possible that using any of the above options could destroy the anodizing on the job work. and is there any other easy method I can use?Please Note that the tap bit is M2 and There are no tap extraction tools for a bit that small on the internet (or Locally Available in India) but if you find one Please post links for the same. Please Be Positive and make this community a happy place. Thanks.

Topic by _Boltz_    |  last reply


HELP - Arduino - "Expected constructor, destructor, or type conversion before '(' token"

I have only just received this Arduino UNO and am trying to teach myself the language. I thought it wouldn't be that bad as I am already familiar with python, however, I was getting loads of errors (most of which I have managed to solve from searching through forums) and have landed on this one. I get this error - "exit status 1 - expected constructor, destructor, or type conversion before '(' token"This is my code...int ledPin = 0; //declares all different pins for different segments of displayint ledPin1 = 1; int ledPin2 = 2; int ledPin3 = 3; int ledPin4 = 4; int ledPin5 = 5; int ledPin6 = 6; int ledPin7 = 7;int inPin = 5; //declares analogRead pinint alphaValue = analogRead(inPin); map(alphaValue, 1, 1023, 1, 4) //maps 1-1023 to 1-4void setup() { // put your setup code here, to run once: pinMode(0, OUTPUT); //declares pin types pinMode(1, OUTPUT); pinMode(2, OUTPUT); pinMode(3, OUTPUT); pinMode(4, OUTPUT); pinMode(5, OUTPUT); pinMode(6, OUTPUT); pinMode(7, OUTPUT); pinMode(5, INPUT); #define low digitalWrite(ledPin, LOW); //defines 'low' digitalWrite(ledPin1, LOW); digitalWrite(ledPin2, LOW); digitalWrite(ledPin3, LOW); digitalWrite(ledPin4, LOW); digitalWrite(ledPin5, LOW); digitalWrite(ledPin6, LOW); digitalWrite(ledPin7, LOW); }void loop() { // put your main code here, to run repeatedly: if(alphaValue == 1){ low digitalWrite(ledPin, HIGH); digitalWrite(ledPin1, HIGH); digitalWrite(ledPin7, HIGH); digitalWrite(ledPin2, HIGH); digitalWrite(ledPin5, HIGH); digitalWrite(ledPin6, HIGH); } if (alphaValue == 2){ low digitalWrite(ledPin1, HIGH); digitalWrite(ledPin5, HIGH); digitalWrite(ledPin4, HIGH); digitalWrite(ledPin6, HIGH); digitalWrite(ledPin2, HIGH); } if(alphaValue == 3){ low digitalWrite(ledPin, HIGH); digitalWrite(ledPin1, HIGH); digitalWrite(ledPin5, HIGH); digitalWrite(ledPin4, HIGH); } if(alphaValue == 4){ low digitalWrite(ledPin, HIGH); digitalWrite(ledPin1, HIGH); digitalWrite(ledPin5, HIGH); digitalWrite(ledPin4, HIGH); digitalWrite(ledPin6, HIGH); digitalWrite(ledPin7, HIGH); digitalWrite(ledPin3, HIGH); } }

Topic by LOU_DEW747    |  last reply


can make the bike running with water only?

Can any one tell to make the 100cc bike by only running with water (hydrogen in water)?

Question by monaman    |  last reply



Convenient djvu to anything readable conversion?

This is a problem I've been trying to solve for the last few weeks. I've finally been given a kindle (New Year presents), and it is great not to have to carry three or four books to school every day - usually it was the thing we read in Literature, some novel I read on my way in the underground, some Physics I have to read and understand and some Physics to help me understanding the first lot. It's been doing a great job, except for  not liking in the cold and getting a bit mad outside, but most of the Physics books I have and can find are in djvu for some reason known only to people who made books on Physics and Maths, so they can't be read on it directly. Is there any way to convert the books to something readable, and better not pdf, because it shows really slow and small and moving around the page is very unnerving especially early in the morning... I'd also love to save the pictures. Any ideas?

Question by gruffalo child    |  last reply


US vs UK flour

Curious observation from my mother's recent 3 months in the USA, she says she is unable to bake well when she was in the USA. Now, given mum is a pretty amazing baker on this side of the pond,  I am wondering why that might happen ? I wondered if  its "American flour", as opposed to "UK flour" - the recipe, would be the same kind of things, memorised over the years, like a simple scone, fairycakes, pastry.  Her main complaint was that items didn't brown, even at the same oven temperatures as she uses here, and after repeated experiments with the same recipes.

Topic by steveastrouk    |  last reply



Arduino Spycam

 I would like to build an Arduino controlled spy Camera platform. The Arduino will just have to switch the camera on or off when a motor is switched on. I will use a camera like (http://www.wtpl.co.in/buttoncamera.html) Any ideas on how to do this with some simple code? Code samples anyone? Kabir

Question by mhkabir    |  last reply


Help! mouse is being stupid!

HELP! My mouse has a clicking problem. In that; whenever i try to click, it doesn't work, and i find myself having to click multiple times with some force in order to get a result, but it's not consistent. Sometimes, it works straight off, and sometimes it takes upwards of 20 clicks, in order to get my computer to do anything. The problem's also isolated to only the left button, the right one's fine. I reckon it's just dirt or something in the mouse, but it's really inconvenient. Any ideas on what i can do to fix it? can i fix it? To give you something pretty to look at, here's a brass cog: Thanks for all the replies. I've just had the case off, and cleaned the rollers. I looked at the switch and there was no dirt packed around it. I clicked the switch without the case on and it still didn't work, which leads me to believe that it's actually the switch that's damaged, and therefore it's not worth trying to fix.

Topic by Vendigroth    |  last reply


If certified in CPR are you required to help in an emergency situation? And if you don't can you be sued? Answered

I am considering CPR certification and I am aware of the "Good Samaritan Law" that protects you from lawsuits for trying to help a victim and failing to save their life.  My concern is, are you bound by the law to help in every emergency situation that arises?  If I choose not to intervene are there legal ramifications?

Question by hicksdm    |  last reply


K'nex M4 Carbine

About time I made an M4 carbine. The farthest shooting/accurate and sturdiest gun i've made to date mostly due to the muzzle loading. WHAT!!! NO MAGAZINE!!! yep, it was abandoned due to horrible range and often jams. It's more of a sniper than an assault rifle and is extremely accurate with a grey rod + grey connector. It uses a modded dsmans barrel for maximum accuracy and distance, accuracy due to the barrel going through the forgrip. I also added a 4-railed foregrip for attachments such as virtical foregrip (shown in pic), bipod, dot scope, lights/lasers, or anything that can attach. Tell me what you guys think.

Topic by Trauts    |  last reply


Help

Hello,I'm Marcin from Greece. I saw yesterday a video about a interactive speaker cloud,but is too expensive for me.I started search about how to build one and I saw Arduino think. (I don't have any experience about it but with instructions I believe I can make it for my nephews) That is my project: I think to use led lights and speakers 2.1. I want to sync the woofer with a specific led strips that gonna make a bright white/light blue light when a loud lighting strike hits and then the following sounds that happens at lower volume to light up the others leds,and some times some random lightening lights. All of those thinks to sync with a sound effect of raining and storm that I will download from YouTube and can play for 1 hour and more. Maybe inwill use ceiling power supply so please someone tell me if that is possible to me to make it and how much gonna cost and if anyone can guide me about what I will need and the commands.Please if anyone can,really I want to make it for the kids because they love it when is raining and hear strikes.Love from Greece.SORRY FOR MY ENGLISH.

Question by marcin93  


I am looking to find out how to convert any letter or image to look like a cut stencil for marketing purposes.

Does anyone know how to convert any letter or image to look like a cut stencil for marketing purposes. I have attached what it is I am trying to do. I have cricut designspace and inkscape.Any help would be appreciated.

Topic by kprescod    |  last reply


Cutting professional stencils

Hi Everyone,Does any one know what machine i would need to cut professional stencils? I dont want a very expensive one nor do i want a cricut. thanks

Question by moldingfun  


Pinterest image rotated, bug?

Anyone having issues with images rotating when they try to share in Pinterest? When I try to share, some of mine have their images rotated 90 degrees. Attached a screen shot. Anyone know a solution to this? I emailed support to see if they have some suggestions.

Topic by jpmarth    |  last reply


MPU6050: ARDUINO 6 AXIS ACCELEROMETER + GYRO - GY 521 TEST & 3D SIMULATION

Buon Giorno Sono istruttore di tico con l'arco volevo applicare questo esempio sul raiser ma purtroppo non riesco a farlo funzionare unllego PDF per verificare i punti di controlloSpero in una vostra risposta Luigi Andreoni

Question by LuigiA12  


Why have neutral plates in an hydroxy generator? Answered

Hi all, I've been wanting to build a simple hydroxy generator for using it as a torch.  I've seen about 500 gazillion tutorials and alot of them talk abour having 3-5 neutral plates between each positive and negative plate. What is the point of this?  Isn't it better to have all plates connected as electrodes? Also, what's the difference between having 5 neutral plates between positive and negative plate, and just having the positive and negative plates installed farther apart (same distance as if you had the neutrals between them)? Thanks!

Question by Morgantao    |  last reply


Will replicate any gun*

Yup you give me a gun and I will replicate it* I just don't know what to build but I really need something to post NOW! I'm trying to build my rep up even more so I'm hoping to have at least 10 replicated guns before the end of this summer. Please leave me a good picture of the gun or a link to it. I have the right to reject any gun that I feel I either dislike (miniguns) are too simple (sten) or too complex (uh...insert some very complex weapon here)*will not make anything that involves explosives unless I feel like having an extra grenade launcher or something. I have enough pieces to make most weapons but still limited so nothing big. I will also not make a random gun with just requested features it has to be a real gun.Edit: To encourage people to vote for a gun I'm going to list the features I hope to include in the gun if I do make it.~List of guns~SAW-1 I'll try adding a chain either for actual loading or most likely looks not sure what else yet.M1 Garand-2 I'll probably try a similar loading style.MP5-1 Detacheable mag plus extendable stock.FN F9000-2 (just one more vote) Bullpup design and...well I'm not sure what elseDragunov-1 Detacheable mag and I'm not sure what else but there will be more.You may either place one vote or add your own. I'm only taking 2 more requests bofore you have to vote on one of the choices. If you vote for someone's idea then please post so in a reply to their weapon so I can keep track of how many people voted for it.I'll probably hold this topic until one of the guns (or an new suggested gun) gets 3 votes so hopefully it won't be too long. Then I'll build the next to reach 3 and so on. New guns will be able to replace the old ones in the list that get built.

Topic by TheDunkis    |  last reply


SUPER accurate servo?

I need to make a device that can move two small servos within 0.01 or less degree rotation (yes, degrees, not radians!).  Currently, everthing I've seen comes up greater than half a degree.  It must have position feedback (stepper without encoder won't work), and the whole thing must fit in a 1/2"x6" tube.  It only needs to move maybe 30-40oz-in, but will always have that load (so backlash isn't a huge issue, but still should be minimal).  A COTS device is best, but it can be homemade, preferably under $50 or so, maybe up to $100 max.  It doesn't need to move fast or continuously, maybe 90 in 0.5 seconds.  It will be run by a microcontroller with a lot of IO pins, and PID control.  Any ideas, products or anything would be great, Thanks in advance. 

Question by jduffy54    |  last reply


what wattage of laser necessary to kill mosquitoes (immediately)?

To craft a gadget that shoots mosquitoes with laser, there is the need to know the enemy's vulnerability. The most needed is the mosquito vulnerability to laser shooting. What wattage of laser is sufficient? The configuration I think is, attracting mosquitoes with some infrared light (or, multivibrator), then shooting with laser. I might shoot with a continuous laser (after infrared path is broken, surely), but zip-zip-zip sort of (threshold activated shooting) is sensible, too.I stated this previously @ yahoo answers, but no (serious) answer wa there.See the question there, http://answers.yahoo.com/question/index?qid=20090505022002AAnd31eFor a full, energy-harvesting mosquito-shooting gadget, a previous question might be related, too. That next question is about the malaria map (for energy harvesting, where necessary). http://answers.yahoo.com/question/index?qid=20090405004614AAsBwtL

Question by ferzenr    |  last reply


Polishing small or very detailed metal parts - the easy way ;)

I should not get hoocked on the cummunity side here again but well, I am bored today...If you have a vintage car, some old steam engine models or even really old clocks then you know my pain.Copper, brass and sometimes aluminium was used and if not cared for in time they nice shine goes first.Dirt and dust come next.And with more time passed we start to consider leaving it as the polishing would take forever.Take one of my "hobbies": old mantle clocks...Literally everything inside is brass.Now polishing a bass backing plate with some holes is quite easy if you have an ultrasonic cleaner to clean the debris out of the tiny holes when done.Even tried to polish a sprocket or fine spring mechanism?If spoked then this is a really painful job.But the same is true if you have old copper and brass ware, like these old stenciled pictures on copper sheets.No matter what you try these jobs end up to take more time than what you imagined and in many cases fine details are left oxidised or filled with the polishing compount.Now imagine you could get rid of these tarnishes and discolorations without cramps in your hand and bying all sorts of polishing products?Sure there are the well known brands that polish a lot of metal with ease by simply wiping over them.But they use harmful and often toxic chemicals and are still no good for really fine details like grooves or emossed stuff.Wearing gloves and protection is often a must and at least I can't stand the stink of them.We all know how to clean our dishes, even how to get the dried on lasagne from last night off the dinner plates.So why not do the same with our brass, copper or aluminium parts?Just use a spongue, rub and wipe a bit, rinse off and let dry.Ok, those who tried before reding the rest might be a bit angry now as it does not work that easy.Well, actually it does, just don't use dishwashing liquid :)Let me give you two of the worst cleaning problems I encountered first:You did some very fine brazing to create something nice from brass or bronze.The flux you can wash off, but polishing the discoloration from the heat and resulting oxidisation will take longe than the brazing job.The other ecounter was the restauration of a petromax style blow torch of alomst 60 years of age - but thankfully it was never used for more than decoration.All brass and a lot parts impossible to polish due to size and being quite delicate.Now we all have ways to spend a lot of time and being creative to use normal ways of polishing.And, yes I did so myself for many years and kick can myself now too.Since we can't do any advertising here and I clearly don't want to promote any brands or harm other brands by rendering their costly products useless I need a way out that helps everyone.So, again, I am not trying to promote anything here!However I noticed someone in my favourite restaurants kitchen polishing some dark copper pot to a mirrow shine in less than 5 minutes!I was shocked and asked the manager to explain what I just saw.He was confused to say the least..."We clean our pots every day, sometimes more depending on what we cooked in them."Sure but what do you use to do what I need several hours for in minutes and with better results?"Just water and soapy powder to shine the metal sir. All natural product."Omg god or Kali! What makes it shine so quickly?"Shining powder sir!" - mind you the poor guy was now totally confused and worried, while I started to loose my insanity.He noticed the look on my face and went into the kitchen.Gave me a fance looking bag that apart from a lot of Indian writing I could not make any sense of stated "Shining powder" on the pack.When the manager saw the look on face this time he laughed and asked "How do you clean your copper pots sir?"I was speechless and just said with much more time and elbow grease...He packed about thimble worth of powder for me to try and said it would be enough for a medium sizde pot, just use a wet spongue and put a little bit of powder on it.And guess what the stuff worked as good as in the restaurant :(I can't even count how many hours I wasted polishing copper or brass parts with fine details.Or engine parts from aluminium with brass parts inside....With this stuff you just wipe and tough cases rub a bit harder and all is done in literally seconds.In tight areas or those with fine details you use a fine brush like those for painting in water colors.And with that and a spongue you clean even the finest details with ease.In an ultrasonic cleaner it even works on areas you can't reach, just wipe what you can reach and see somehow and it shines.Now if you want this magic stuff and check if the guy here is just pulling your leg then be prepared to pay a lot of money.200 grams of this powder will set you back between 5 and 15 bucks depending on where you shop.That is enough clean about 300 midsized copper pots or a few hundret meters of copper piping....Just ask for shining powder in your Indian grocery store ;)We all waste money or stuff we don't need, so if you have coper, brass or aluminium to polish then try washing it the Indian way - just for fun of testing something else.And if after that test you think the few bucks and information was well worth it than please post your experience with the powder in the comments below.I hope all those members here working with these metals will read this too, so if not help me to spread the word please ;)I am struggling to upload some pics I have taken from the blow torch but will try again alter once I reduced their size.If in doubt I will upload them to a hoster and link them.Disclaimer:I don't advertise, I don't promote!However I am so pleased with this dirt cheap product that I use it now as my prefered and natural option.For this reason I think it is worth sharing.It is not a magic cure! If you have pitted areas, solder marks or brazin coming out of joints it will not help.Same for scratches, they still require abrasive polishing to be removed.But normal dirt from being displayed for years, oxidisation and even slight discoloration from corrosion will vanish.And if the surface has a good polish underneath all this than it will come back with ease ;)

Topic by Downunder35m    |  last reply


Arduino or Teensy coil winder - any code already out there?

I am in the process of deciding on a normal 8bit Arduino platform or a Teensy for my coil winder project.A found some interesting projects online, some with the code available too.But I was wondering if someone already implemented more than just winding a coil in such a project?At Krux.org is a nice winder based on a normal Arduino while the Alba winder uses a Teensy already to gain more precision and speed I guess.Misusing some printer or CNC code to be able to generate coils by G-code sounded nice at first but turned out to be more complex than actually required.My goal is actually rather simple despite the size and all, so let me try to explain what I want to be able to do:Have a modular winder setup so basically any winding task can be done with just two stepper motors.One for the spin, one to position the wire.Additions like limit switches and external counters are nice but usually not required for such a task if the the code is properly done.As a basic winder like all the examples out there it should be possible to just enter the wire diamter and number of turns and then push a button to wait for the finnished coil.In theory things like pitch or spacing can be calculated externally and then entered as a fictive wire diameter but of course this would be not user friendly enough ;)For special RF coils it is often required to keep an even turn spacing as well as creating a coil with many layers.So far I have been unable to find any usable code for this purpose that does not require glue, guides or at least waxing the wire.Although this seems to be simple enough, when adding things like a display and counters it soon starts to get messy with timings and steps.Is there anything out there that works properly on a 8bit processor with reasonable speed?Originally I wanted to use an OLED with touchscreen.This turned out to be too much for the timing on a Mega.Without messing around with timers and interrupts it seem a 20x4 LCD is the only option.Even then the refresh must be in sync with the tart of a new turn as otherwise the motors miss some steps here and there.These things run a 3D printer or little laser cutter with ease, so I am definately doing something wong with my approach here LOL

Topic by Downunder35m  


Campfire powered foundry?

Hey guys, Ive been checking out a few of the foundry instructables here, and I want to make one. I have 2 problems. 1, I don't have any charcoal, and two, I don't have a fan. So I was wondering... is there a way that I could make a foundry that would get the heat from a campfire or firepot? I'd there are 101 uses I can think of for molten aluminum.., Thanks in advance! IaC

Question by I_am_Canadian    |  last reply


Help - wiring up bathroom extract

Hi all. I am planning on installing a bathroom extract fan. The fan will be ducted to a small toilet and to my shower, this it will be extracting from 2 spaces. I would like to connect the fan to the lights, so when either (or both) of the bathroom or toilet lights are turned on, then the fan will turn on. Would this be possible?

Question by Waynne-EdwardR  


How to make a laser moquito killer

I would like to make a DIY laser mosquito killer. Can anyone help if experience. thanks

Question by abimboos    |  last reply


3D Printer Thermistor in a K type thermocouple

Hi all,Quick question before I butcher something unnecessarily.Can I connect a bog standard thermistor as found in Chinese 3D printer (of which I have spares) to a k type thermocouple plug (I have none) and use it in my k type thermometer?Or should I just buy the slightly more expensive correct lead?I want to monitor temps @ the heat break of a new hot end.

Topic by Squibo    |  last reply


Going to sleep with HP monitor

So I am trying to help my grandparents fix there computer, they have a dell pc ( don’t know what exactly ) and a hp 22cwa monitor. The monitor will stay on in tell I plug the hdmi in then it says no signal then goes to sleep mode, I have tried new mouse and keyboard on the computer, as well as using another cord on this monitor and pc but neither work. I did take the monitor to my pc and used the same cords and it instantly worked with both cords just fine. Before today this monitor has been working for almost 6 months with no problem and now is randomly doing thos

Topic by huongrio    |  last reply


Entries in a contest

How many entries can we give for a contest

Question by Gagan jain    |  last reply


How to reverse/invert/mirror a computer screen?(not rotate)

Hey guys. So I'm working on a project, but I need to know how to reverse my computer screen as if it was in a mirror. That way, when you hold up a mirror to the computer screen, it appears normal. I've dug through many articles on the web, and I couldn't find anything that worked that hadn't been taken down. Does anyone have any software that could do this?

Question by RedCthulu    |  last reply


I am looking for a 220v/50Hz to 110v/60hz step down transformer - any help please? Answered

I want to purchase a computerized sewing machine for my wife from the US, however this machine is VERY sensitive, and manufacturer does not recommend running it on different voltage than 110v. I have checked with them, and the required input for it is:2.4  wattage. The amp is .02 and the voltage 120. I have not managed to find a reasonably priced step down transformer which can also transform the frequency - only one, but it costs a few thousands of dollars :)Please, help! This machine is not sold here, not in Europe, not even similar model. One answer I've got from a company specializing in such reliable converters: Since your sewing machine is computerized and very sensitive we do not feel confident that it will work properly with a voltage converter because of the cycle or hertz difference.  Here it is 60 hz and Israel it is 50hz and converters do not change the cycles. your sewing machine may be adversely effected. The machine I am talking about is this: http://www.amazon.com/gp/product/B003EPLBMO/ref=gno_cart_title_1 Thanks!

Question by Carmageddon    |  last reply


Sorting My Favorites

Hi, long time viewer of this site, first time poster in this forum, I was wondering if anybody knew whether there was a way so I could create different files/boards centered around different ideas, so stuff about building musical instruments can all be in one location, and so on and so forth, sparing me the trouble of having to scroll all the way through my favorites just to see what all is there. Someone want to help me out?

Question by jlynn31  



Plushie: CAD program for Stuffed toys and Inflatables

This is an awesome tool for designing teddy bears, stuffed animals, and big inflatable items with complicated shapes. It's called Plushie, and it looks incredibly easy to use. It's kind of like Sketchup, but for blobs of stuff. You just start drawing in 2D, and it makes smart guesses at the volume that you're trying to create. Once you're done, it generates the pattern for you that you need to cut out. Here's their cool video: It's a Java-based Windows app. Someone should definitely make something with this!(I found this via the We Make Money not Art.)

Topic by nagutron    |  last reply


Split Tesla coils anyone?!

I am collecting data in the form of old pics, patents, newpaper and magazine articles as well as just doing things.Tesla coils are fun but is anyone experimenting with the original "multiplying transformer" that Tesla created?And before you say, sure I have a Tesla coil......I mean:Large diameter primary coil with one part of the secondary in very close proximity while the other half of the secondary is located at the center ;)

Topic by Downunder35m    |  last reply


Help me in led different modes (led Flicker , led flow with timer set,etc.) control using mit app inventor

Help me in led different modes (led Flicker , led flow with timer set,etc.) control using mit app inventor and bluetooth.

Question by rutukesh  


Projecting a 'target' dot from the barrel of a toy Sherman tank

I would like to modify a 1:35 scale model tank (it's about 6-7 inches long) so that the barrel projects a dot on the wall and I can determine whether or not 'firing' the tank hits a target.A low-power laser would obviously project the dot, but there are two big problems: the risk of it getting pointed at someone's eye, and the logistics of mounting it in the chassis. Regarding the safety issue, that danger could be lowered by limiting the laser to a 0.1 second burst each time. That's still not safe enough for my tastes, so I don't know whether I'm willing to go that route. And as for the logistics, the turret of the tank will be full of servos, gears, etc., so the laser unit would have to be in the hull of the tank, with the beam channeled to the barrel somehow. Would a length of fiber optics do the trick? Does anyone have other suggestions for channeling the laser?It would be easier from an engineering standpoint to mount an ultra-bright LED in the barrel, but is there any way to focus that into a dot?And finally the target would have to be big enough that there's some chance of actually hitting it - I'm thinking the size of a quarter. I haven't found any laser/visible light receptors that big - any ideas?As an aside, I don't like posting questions without having done some legwork first - I have actually researched this, but haven't found useful info...Thanks!

Question by hawpond    |  last reply


I need help understanding networks

Hello. i have a few questions about networking, which I was hoping some of you could answer?First off, when I connect a switch to a router, how does the switch get multiple IP addresses for each thing that would like to connect to the switch if the switch is only connected to one port?That's it for now.

Question by Ruby Laser  


Find or How to Replace Old Dried Out Gaskets in a Set of 4 Ceramic Kitchen Canisters

We have a set of 4 ceramic kitchen canisters that are so old the foam seals, or gaskets, have dried out. I cannot find replacement gaskets anywhere. They were made by an individual, so there is no company to write to for replacement parts. Does anyone know who sells such gaskets? Foam or rubber or silicon will work.Or, is there a way of making replacements? I've seen amazing things done on "instructables" with silicon; molds, fake heads, toy octopus, etc. But I have never worked with it. Is it OK for a seal that will be in close proximity with salt, sugar, flour?The canisters are glazed ceramics that some individual has made.Attached are photos of the canister, mating surfaces, and existing gasket.Any suggestions will be appreciated.Thank you.Phil Brown, Southwest Wisconsin

Topic by oghk2000    |  last reply


How to produce 14,000 cubic feet of hydrogen? Answered

Okay, here is the deal. Me and a friend where thinking about filling two weather balloons( http://www.ebay.com/itm/GIANT-Weather-Balloon-Meteorological-Military-8-Dia-/330626487344?pt=LH_DefaultDomain_0&hash=item4cfadfd430) with a lifting gas, sending it up with a camera and gps-cellphone. Now, we have everything else figured out but how to get hydrogen, as it is the lightest gas. Is there any way to produce those quantities of hydrogen within a 6-36 hours? I figure I'd ask here because there are quite a few hydrogen powered vehicles here.

Question by bretta    |  last reply


Identifying plastic so I can weld a repair

I am repairing a broken wheel on a old lawnmower for which spares are not available. The hub (holding the roller bearing) has broken away from the rim and tyre. I've managed to weld the two parts back together using the hot air gun on my rework station but some small pieces are missing and I'd like to replace these and reinforce the welds by adding material.It is possible to buy rods of different plastics to carry out these repairs but I need a better understanding of the material I'm working with. It is an opaque white plastic with a greasy or soapy feel. It melts relatively easily (I used the heat gun at 180 degrees C) and bonds back to itself well. I suspect it is a polypropylene of some flavour - straight Polyprop, HDPE or LDPE.I don't have scrap material to test without removing some from the wheel. Any thoughts on what it is likely to be and do I have to know exactly which it is or will the different materials bond with each other?

Question by Henmarsh    |  last reply


Big block wooden letters

Can anyone make the wood big letters for me? I do t have the tools to make them and dont know how to use the tools if i had them..if someone would like to make these for me please call me at 248 636 9735 or email me at deonique224@yahoo.com

Question by MzNeko  


Looking for Used Lighter

Looking for used disposable lighters, preferably bic, for an art project for class about sustainability. Any size will work. please let me know if you have some I will be happy to pay for shipping.Best,Spins

Topic by jspins123    |  last reply


i need a detector for my crystal set, PLEASE HELP

I need a detector for my crystal set,but don't want to use a geranium diode or that  "cats whisker detector" that i cant get to work. PLEASE HELP ME, I NEED HELP!!! the cats whisker detector i used was a blued piece of steel / carbon (or pencil lead) from Youtube:   [search]    [make magazine foxhole radio]   if a mineral like geranium, galea, iron pyrite (fools gold) work well, i would like to  know how to obtain it without buying anything online? (i mainly don't want use a geranium diode because one i had burnt up. another reason why i don't want a 1N34A is because it isn't available at any "real physical" stores (like Radioshack ) i don't mind to use another type of diode. what about a schottky diode? do they sell any @ radioshack? and will it work?

Question by -max-    |  last reply


What can I use for painting a black Evo desk to a very pure-white color?

I want to be able to paint a black evo desk to a white color that would look nice with an LED lit room. Please give me some suggestions or advice as I attempt to do this :)This is what I currently have. After going through the options at checkout.Evodesk Shape :Ergo Edge Renew Recycled Wood Finish :Carbon Black Desktop Edge :Ergo Edge ($79.00) Desktop Size :30x84 ($349.00) Frame Color :Carbon Black Storage Pods :No Storage Desktop Highrise :No Highrise Controller :Programmable Memory ($59.00) Keyboard Platform :Carbon Black ($139.00) Freeport :No Freeport Cable Management Tray :Carbon Black ($99.00) Warranty :Standard Warranty NOT SELECTED Harman Kardon Speaker System :No Monitor Arm :No Treadmill System :No Metalix Glass Chair Mat :No CPU Mount System :No Anti-Fatigue Mat :No EvoFlex Cable Management :No Evodesk Casters :NoThere is also water damage mark on the desk. Is it worth fixing it? it is water damage left over from a cup with no coaster. Any advice on possibly fixing this would be much appreciated. :)

Question by aquerol    |  last reply


Moving Ears

Hello,I was just wondering if anyone could help. I have an idea for something I want to build, however I just need a push in the right direction.I’m working on a costume with antenna ears. I could just make them static however I want to add a bit of movement. Basicially I want them to, when I tilt my head down, the ears flatten (think a cats ears when angry) and when I lean my head back, they point up. The rest of the time they stay in the middle.I want them to be automatic. I really hate triggers or controls, as soon as someone notices how you are operating it, the illusion is ruined. I also don’t want to use electronics (the sound of a motor).I am absolutely sure I can oull this off, however I’m not sure the best way of doing it. I was thinking fluid filled tubes, as the water exits one it enters the other. Or the mechanism in dolls so they sleep while lying down.Does anyone have other ideas or pointers?

Question by Reddkryten  


Chaining 4 74HC595 shift registers together

I have a question about chaining 4 shift registers together.I am going to be sending data to four shift registers and my question is this, when all four are loaded and latched if I send more data is it possible to only send data to the first register in the chain without the others losing their values?

Topic by mbcharney    |  last reply