Topics


How much angle or curve needed for bike trailer tow-bar?

I want to make a trailer for my bike, but am confused about all the various types/styles of D.I.Y. tow-bars I see being made/used...how does the curve/bend of the tow-bar affect whether the trailer will track correctly behind the bike? If the trailer does not track correctly behind the bike then the tires will be ruined over time, and it will cause more 'drag' (harder to pull). I understand that the tow-bar needs to be able to clear the bike's back tire when turning, but if I put the wrong angle or curve in the tow-bar will it cause issues with keeping the trailer straight behind the bike and tracking properly?So how does someone determine the correct angle/curve of the tow-bar, besides trial and error and possibly wasted materials? Thank you for your time and assistance.

Topic by Bsrlin    |  last reply


PWM to MPPT solar Charge Controller

I have an Hybrid Solar Inverter with 50A PWM solar charge controller inbuilt into it. It works on 24V battery bank. I am having 800Watt of PV module installed in the system. As my inverter is having PWM charge controller, I am not able to harvest maximum of power from panels. I want to know that, is there any arrangement or device which can be put in between PV panel and my Inverter which can increase efficiency or can act as PWM to MPPT converter for my Inverter? My Solar Pannels generates often 39V but I couldnt utilize the surplus power as it stepped down to 24 Volt.

Topic by Shashi BhushanS    |  last reply


Defeating Metal Detectors at Concerts? Answered

I plan to bring a camera to the future concerts of a singer. I believe fans have a right to do so. The camera will be hidden from sight, but I need a way to shield it from any metal detectors that may be used. Using a metal detector designed for coins, I found that steel wool can hide steel items from the detector in ferrous mode. But switching the detector to non-ferrous mode quickly reveals the steel wool. I have found no other material that has any desired effect. Perhaps I could carry something that transmits a jamming signal to the detector. Has anyone here had experience working on this problem and can offer a solution? ~Bob~

Question by ShutterBugger    |  last reply


B212D active speaker amplifier troubleshooting - driver stops after running for 20 minutes

B212D active speaker amplifier troubleshooting - driver stops after running for 20 minutes.Every time I switch on the speaker, it works for 20 to 30 minutes and after that the driver stops but the compression driver still works. Right after that, if I power off and power on then the driver works for one minute or so.Once it is cooled, if I start it again, it repeates same as above.Is it a capacitor issue or any other weak component? How to diagnose and fix it?It is a product from 2009 Behringer.Please help.

Question by bnsahu  


Would layers of microfiber cloth work as an effective N95 air filter substitute?

Hello, as many of you know, there are some devastating fires in California right now. My family and friends live nearby to these fires, and are being exposed to toxic levels of smoke and air pollution. Due to the disaster situation, many stores that sell n95 masks have sold out or are price gouging people who need them. I have been trying to figure out an effective solution where they could use household materials to approximate the particulate filtering properties of the n95 filter. I was thinking they could make some kind of respirator style mask with the main face mask made of cardboard and duct tape, ad make a "cartridge" for the mask out of a cardboard cylinder stuffed with layers of microfiber cleaning cloth, or potentially other air filtering material, or even activated charcoal if it is available.I understand that such filters are not an ideal substitute but when the air is completely off the scale for toxicity, anything is better than nothing. Does anyone have any input on this? Is this worthwhile at all? Is there another commonly available material that you would reccomend other than microfiber cleaning cloths? -ilpug

Question by ilpug  


Behringer B212D PA system main driver works for 10 to 20 minutes before stops every time

Behringer B212D PA system main driver works for 10 to 20 minutes before stops working. but the compression driver continues to work. If I power off the amp for a second and switch back again, the main driver works for minute or so. After couple of hours if I switch on the amp again, same process repeates. I am able to hear the main driver working for 10-30 minutes only, every time I use. after that, just the compression drivers shrill sound continues.The amp is also not that Hot at that time. It is an unit from 2009.Is it a thermal issue? Or any capacitor weak? Or any other weak component?Thanks a lot in advance.

Question by bnsahu    |  last reply


Circuit design

Hi, I’m hoping someone could help me. I’m looking to design a circuit for a college project that controls a 240v light. The circuit and light will be controlled by a switch however when the switch is first turned on the light needs to remain off (no power supplied) regardless of the amount of time the switch is on. If however the switch was turned on off and on again then the light needs to come on. Any ideas of a circuit and components required to produce something like this? Your help is greatly appreciated.

Topic by Worby10    |  last reply


Using a projector with a timer switch? Answered

I am trying to set up an art installation which will involve a projector projecting a video piece in the middle of the night when unattended. I was planning on connecting it up to a laptop and somehow using a timer switch. I realized though that the projector may go to sleep or may not work using this timer switch option. I would set the video projection up with blank space on the video to correspond with timer so that for example if I wanted the projector to come on in five hours time I would put five hours of empty space at the start of the video meaning that whenever the projector comes on it is timed with where the video is at that point and the video will play. I know there are holes all over this so any advice would be much appreciated! Thanks, Rachael

Question by co701rf    |  last reply


How do you make more accurate tools from less accurate ones? Answered

I was wondering, in a general sense how people make more accurate tools from less accurate ones. More specifically, I was reading about reprap and it said it was possible to make components of itself from other previous repraps. However, the errors in them would compound and make less and less accurate/precise models. Therefore there would be some limit to how many times it could replicate. But, for instance. A lathe requires an accurate/precise leadscrew to control x axis motion. Using a lathe it is possible to make another leadscrew however this would be less accurate/precise than the one already on the machine. So for my true question. How do they make more accurate ones than the previous ones. If all the current lathes in the world are +- 1mm then how would you make the next set of lathes that are more accurate/precise than that without a piece of machinery that originally had better accuracy. (sort of a chicken and egg problem) Is there some type of machine or algorithm or something that allows a machine to make something that is more accurate/precise than itself. Thanks

Question by louey    |  last reply


I am looking for a sensor that measures "pressure" but I don't know what to look for.

I have an idea, nothing revolutionary, but it would perfectly solve a problem that I have in my woodworking shop. I need to be able to tighten a very small toothpick-sized piece of wood in a small meral vice, to a very specific level of "squeeze", and then release the vice, and repeat that exact "level of squeeze" over and over. Can someone point me in the right direction of what these "pressure measuring devices" might be called? Ideally I could use this pressure gauge (sensor) in tandem with a small display and an Arduino, Raspberry pie, or some other logic device that can interpret the output from the pressure sensor and send that output to the little display.Thanks for your help guys!

Question by Dolmetscher007    |  last reply


Best way to cut corrugated plastic?

On the day after the elections, I collected a bunch of corrugated plastic political signs that were going to be recycled. My plan is to turn them into a small geodesic dome, similar Nasa’s Hi-Seas dome for my daughter to conduct scientific missions in the backyard.Is the easiest way to cut these signs into the necessary triangles with a razor and a straight edge? Can I use a circular saw or skill saw to cut them faster or cut multiples at once?

Question by Erfunden  


How to control someones computer with command prompt?

The title is the question.

Question by chanman789    |  last reply


Why does the water in my rice cooker only gets warm and not cook?

I have a 60 cup rice cooker with two functions, cook and warm. it use to cook just fine for the 4 times i used it and i tried several time after but the water only gets warm and does not cook the rice. what can be the problem.

Question by CourtneyK11    |  last reply


Nextion Display with Raspberry Pi3 B+ Does it works or Not?

I am strugeling with several Posts concernig Rp if it works over TX/RX with Nextion Display.I used following instruction https://www.itead.cc/blog/how-to-use-nextion-to-wo... and got following error: [SDKERROR:itead_serial.c.298.Serialavailable]->Serialavailable failed!the Only Tread that I found that there are trouble is as follow: I don't know if that's gonna be useful, but I switched from a RPi 2 to the RPi 3 yesterday and I noticed that the serial port won't work anymore and I figured out why. On the RPi 2 the Serial interface is "/dev/ttyAMA0" and on the RPi 3 it is the "/dev/ttyS0". (Yes, on the RPi 3 the ttyAMA0 is still present, but won't work) – FusseldiebApr 20 '17 at 12:38Does somebody know if I got a chance to get Nextion working with RPi? Thanks a lot

Question by FrancisH26  


How do you fix a sewing machine that won't stop running?

I have a great old sewing machine and it would work fine if i could control the needle with the presser foot. It is a Zig Zag model E-388 Precision Made in Japan.

Question by Yobetty    |  last reply


Best thread for stitching and sewing leather? Answered

It has been recommended by many leather experts to use a strong thread for stitching or sewing leather. Would someone please inform me of the right or best thread to use? Thank you very much!

Question by blkhawk    |  last reply


How to get an instructable featured?

Hey can i know how to get an instructable featured my friend got his in a day?

Topic by iloveandroid    |  last reply


What can I do with Pro?

I recently recived a free 3 month pro membership for having my Instructable featured. (See the featured Instructable here.) But I don't know what I can do with Pro! What are some pro benifits, and how do I use them?

Topic by Chikpea    |  last reply


An alternative to expensive grinding stones

For some people buying a decent grinding or honing stone is a lifetime investment.Prices of over $500 for a single stone of a very fine grid are not uncommon.But what about the average Joe who just needs to sharpen a knife or tool every now and then?If slicing and dicing is not your living than investing in a set of diamond plates might be better than getting a set of stones.But there are limitations, firstly their size and then how long they last.The later is really important if not used correctly as even diamond toold can be ruined quickly.In some case these small sharpening tools are hard to handle.The bigger plates can still be a pain if they don't come with a proper mount.Well, and if you forget to clean them after use and put them in a dry place it will be quite hard to remove the rust.A nice alternative I found is sandpaper, specifically sandpaper on a glass plate.Good wet and dry sandpaper is available from almost gravel to a 10.000 grid, above that you might have to make a special order.In general the finer the grid the more you pay due to the ingredients.I use a glass plate from and old scanner as they are both heat proof and really strong, window glass is not recommended here.The glass is covered with strips of kapton tape for the ease of later cleaning.The tape is then evenly covered with a contact glue, preferably the spry king to get an even cover.Same for the sheet of sandpaper.I try to get the glue over the glass edge a bit and to have at least two sides of the sandpaper going over an edge.Just to have an area to work close to the edge without risking to lift the paper off.Once a sheet is too worn I place the plat in the oven for a few minutes so the glue softens and peel the sheet off.If too much glue remians on the tape I replace it before I put a new sheet on.Of course you need a bunch of plates although it works fine with two different sheets halfing a plate.The thing works best under slow running water, so use your tinker skills to come with a suitable frame and water supply ;)But even with just a spray bottle it is a cheap way to replace a costly stone, especially if you do require a bigger surface area.

Topic by Downunder35m    |  last reply


I need to know how to make a dc male jack with battery clip

I have a dc male jack and a battery clip.separately.i need to know how to connect .this is from a project i saw in instructables.please help.

Topic by ABhiramS5    |  last reply


Turning a set of stairs into a heating element?

Hi All, My thought was this, I live in New England and of course there is a lot of snow and ice in the winter.  I am going to have an exterior stair that leads to the third floor of my house and keeping them snow and ice free in the winter will be  a major PITA!  I have looked at a lot of different heating products but none seem optimal.  I was thinking, after remembering small heating elements, similar to the coil you could just put into a glass of water to heat it, why couldn't I just turn the steps into a low temp heating element powered from the house's electricity? Is this totally absurd or should it be possible?  Any ides? TIA, Aaron

Question by offthedeepnd    |  last reply


more output current with LM317 ?

Hi, for some time I have been wondering if I can make LM317 to output more than 1.5Amps. After many hours of searching I found that I can achieve this in 2 ways. The circuits are in LM317 datasheet which can be downloaded from here : http://www.ti.com/lit/ds/symlink/lm317.pdf 1- By using a transistor with LM317 (page 16) . 2-By using several LM317 regulators in parallel and using TL080 (page 15). Second one seems better IF load is equally divided between regulators, it also has the benefit of producing less heat when  high currents are drawn. My question is: will the second circuit (LM317s in parallel) work and output more than 2Amps? is load equally divided between regulators in this design ? can I replace TL080 with another IC ? By the way, there is a circuit in page 12 called "tracking preregulator" , what is the purpose of this design ? PS. I know there are switching regulators which output more current, but I'd like to experiment with LM317.

Question by ehsan_zt    |  last reply



Why don't old /community/* urls redirect to new /topics/* urls????

All of the older links to a topics on Instructables link to instructables.com/community/page urls, but a while ago (I'm not sure exactly when) all the /community/* pages were moved to /topics/*. Clicking the old /community links returns a 404 error, which is annoying because then I have to manually replace the "community" with "topics" in the url. So my question is, why can't all the /community/*/ pages redirect to their respective /topics/*/ pages?

Topic by scitronboy  


Electric knife sharpeners.....

Back in the day we already had these tiny grinding wheel like tools in the kitchen.Plug it in, press a button and slide the knife through.The blade was supposed to come out razor sharp if you trusted the ads....For obvious reasons a grinding wheel moving along the edge is not a good thing, especially not if both te up and the down movement work on the edge.As soon as they appeared they disappeared only to emerge years later in a "modern" form.The latest incarnation now comes with ceramic wheels to give an even sharper finnish LOLThe problem however is still the same, first the action of the whells then the fact that it is next to impossible to get different angles.They are really only good for some knifes you use in the shed if nothing else is available.A now much hyped electric sharpener is basically just a tiny belt sander with guides attached to it.And don't get me wrong, they come in handy for certain works.But if you ever used a belt sander on a flat piece of steel you realise that it is quite impossible to get a flat surface finnish.The belt curves around the edge and this results in a curved or beveled edge.Obviously the claim to sell these is that a beveled edge has superior strength and sharpness compared to a straight angled edge.And then there is the ability to adjust not just the sharpening angle but als the grid of the sandpaper.The finer you go, the better the result and sharpness...Now if we trust those who create swords from raw iron ore then something is wrong with the belt approch.These guys would tell you that you should always use a flat stone and to slice a piece of the stone.But also that a beveled edge is a sign of wear, something a good butcher will confirm.The angle of the edge party affects how sharp and durable the edge will be.Usually there is a compromise between blade thickness, meterial and edge angle.Just go from razor blade to an axe and include severel types of knifes between them.So a beveled edge in my opinion is only good for brute force tools but not that good for fine slicing and dicing.I tried to sharpen a wood chisel on one of the belt sander toys...It turned out to be far less precise and the edge was not fully straight.Could be down to lack of experience but if you ever try it let me know your results.The produced edge was also quite unusal and often bad when used as intendet.Far more chipping than cutting.Difference between straight angle and beveled angle when using a knife.You might want to do some lonely woodworks while fishing.A good knife now just eats into the wood and lets you cut and slice pieces of at almost any angle of the blade.With a beveled edge however you face the problem that your working angle is drastically reduced.Tilt the knife a bit too much and you suddenly just slide off the wood and into your flesh.If you grind and hone a knife to a 20° angle on a flat stone than from all angles above 20° you can cut.If you belt sand a knife to a 20° angle you end up with a bow over this angle.The actual usable working angle can be as low as 40° on a thicker blade.In theory it is possible to overcome this bevel problem.Sanders with a backing plate for example or by using just enough pressure to take material off.The first will destroy your belts quickly, the second takes forever.Some people just sand the knife at an angle to the belt, so instead of having the belt running at 90° to the edge it runs at 60 or 40°.Reduces the buckle but also the sharpness as the actual edge is now rounded.The only real way to sharpen a knife would be with a cutting or slicing motion, something that usually cuts your belts once the edge becomes sharp enough.So should you use them after all?As with all tools it comes down to quality and how you use the tool.If you know what you do and what the limitations are an electric sharpener can save you a lot of time.Someone with a desire for razor sharp knifes and tools might only use them on the lawn mower...You can however very well use sandpaper for sharpening a knife, which I will explain in another post....

Topic by Downunder35m  


how to make a hybrid go kart ( i.e., with the motor and the engine)..?

I want the go kart to start with  the motor and after it reaches 20-30 speed, it should run with the engine.. can anybody help..? How the transmission will take place..?

Question by sachin jain    |  last reply


From Anime to Reality

Someone was such a fan of Akira that they recreated Kaneda's bike from the manga and the movie. The bike is actually street legal and I'm looking forward to reports of it tearing it up in Neo Tokyo in vicious street gang battles. Extra bonus points if it manages to create light trails. Link

Topic by fungus amungus    |  last reply


(EMP generator)How can i make a long range EMP generator?

I have watched many video in youtube about, how to make EMP generator. But those EMP's range are really small, I want to make a EMP that can disable any electric device around me like, Disabling all the device in my room. So can Anyone help me with this??

Topic by harryt47    |  last reply


What would happen if you used a 24v battery pack in an 18v cordless drill? Will this damage the motor? Answered

Thinking about overclocking some of my 18v power tools.  I can adapt 24v battery packs to fit into them.  Obvious advantage is they will run faster and should run longer with the extra power.  My only concern is can this damage the motors?  I think the only real risk is overheating but it I take steps to avoid that would everything else be okay?  I've also considered hooking two battery packs together to run an 18v saw at 36 volts.

Question by etcmn    |  last reply


YouTubers who also post on Instructables

Who are your favorite YouTubers who post their project tutorials here on Instructables? For me the list isn't that long, looking to make it longer...Darbin OrvarEvan & KatelynPaul JackmanBrian LoughGlen (DIY Creators)Jen FoxbotJohnny Brooke (Crafted Workshop)Barb Makes Things

Topic by bekathwia    |  last reply


Microwave stopped heating and I fixed it.

Our microwave is about two years old and it stopped heating. The fan ran and the carousel went around, but food did not warm. I took it out of the upper cabinet mount and opened the case. I know about the big capacitor and discharged it with a screwdriver after disconnecting the power. For extra safety I clipped a jumper wire on both terminals. I watched numerous videos at YouTube on troubleshooting a microwave and on testing the various major components at home, but no component showed any signs of failure. Then it began to work again as suddenly as it had stopped working. About ten days later, it stopped heating again. After more testing, still no components showed signs of failure. But, I did squeeze the female spade crimp connectors a little with a pair of pliers before connecting them again so they fit more tightly when reconnected. The microwave has continued to work as it should. My wife remembers a time a few months ago when she ran it and ran it to get something to cook as she wanted it and the microwave stopped because it was overheated. I suspect a connection was weak and heated the metal in the connector enough that it became weak. Later it failed intermittently. We could have called warranty service, but we did not want to wait. Knowing what I know now, I doubt a serviceman would have patiently checked for weak connections, but would probably have simply replaced some parts. When those did not really solve the problem, the microwave would have been condemned and replaced. A replacement oven may not have matched our other appliances as well as our present microwave does. Test procedures for components in a microwave are different than they are for similar components used in (for example) a sound amplifier. This applies especially to the high voltsge diode. Do not connect a voltmeter to the high voltage side of the transformer. When running the microwave, be certain to have a dummy load in the cavity, like a cup of water. A very useful test that checks for power to the transormer primary is to disconnect the primary side transformer connectors and attach aligator clips from a voltmeter to the transformer leads. Then run the microwave for a few seconds and check for a full line voltage reading each time. A clamping ammeter to measure line current helps because the sound with the magnetron working is not too much differnt from the fan and carousel running without the magnetron working, but, it is easy to see the extra needle deflection when the magnetron is also drawing current.What seemed to be an expensive problem had an easy inexpensive solution.

Topic by Phil B    |  last reply


An idea for highly directional and loud loudspeakers

I am currently playing around with vibration experiments.Mainly in the ultrasonic range though.But when messing around with some vibration speakers I found a not so well documented misuse for themEveryone wants a big TV these days but once you have it the sound often turns out to come from a tin can.Those with a good entertainment or at least stereo system won't mind hooking the to it.The rest usually opts for a sound bar or how I like to call them shredderbox.Sooner or later they just fail to produce the sound you had on the first day - or they cost a small fortune.What is the secret to a powerful speaker?Firstly efficiency.Secondly the design.You need the right material to produce a more or less even reaction at all intendet frequencies.The design makes sure those frequencies that need extra attention get more volume output, like by using a little pipe for the low frequencies.Some even include a dedicate speaker for these low volumes.What if you could just build you own soundbar on a budget?If you have a failing soundbar with the actual speakers as the problem you could salvage the electronics.In case you can make do with headphone input or RCA connections than any cheap amplifier will do.Leaves the speakers...Vibration speakers are still underestimated for their uses...I tried the the usual approach of using a glue on vibro speaker:Place it on surface tha gives a re more or less decent sound.The thing is though that there is no ideal surface for them.A table can sound like the highs are missing, a hardwood desk might not produce any low frequencies while a window or plaster board wall bring the problem of wiring and vibrations.To check the reactions of sound on different media I, one day, mounted one speaker under a big tin can.Right in the center.The fun hit me when my tests with water were over and tried to play a song with the empty can.Of course there was some degree of tin can sound but the directional qualities together with the wide frequency spectrum made me experiment.The key is to find the right material and shape!You want something that is hard enough to vibrate properly but soft enough to allow for lower frequencies.I tried pipes, boxes, old plastic containers....But nothing seemed to provide a broad and even sound spectrum without distortions.If you vibrate a surface then only at certain, resonant frequencies destinct patterns will form if some dust or similar is place on the surface.In all other cases there is only chaos.Preventing the harmonics to form prevents harmonic vibrations to build up to distortion levels.Like it or not but waste seems to work just fine as a speaker ;)I made a plug to fit reall tight into a 2 liter juice bottle neck.The original plastic cap is just too soft.A vibro speaker glued onto the plug and the bottom of the bottle cut out and the soun was quite impressive.Proper use is however limited as the speaker would need to be mounted upright.Next thought was to utilise the bottom of the bottle too.By cutting a round hole in the side of the bottle I got an even more directional speaker with a better response to low frequencies.Placement of said hole of course affect how certain frequencies travel and where nodes can form.The size might also matter as the hoe itself, or better the material around it can get resonant at certain frequencies.You can cheat at bit though by using sticky tape, duct tape and so on as dampening meterial in badly affected areas.Especially with a wall mount for the speaker and the bottle hanging down behind the TV the effect is good compared to a standard shredderbox. The above design is certainly not for everyone although I think it has a wow factor to it if you show a decent sound coming out of a juice bottle ;)My next step was trying to find out how more fancy designs could work.So just stop reading here unless you like the idea of creating speakers that should not even work.Back in the old days we had more than just the speakers with magnets and cones.Anything that can vibrate can produce sound.It all depends on how much of it we can actually hear.My first exotic idea to really misuse a vibro speaker is a vibrating harp.Does not need to be in the classic shape though.A string in a resonance box, like a harp, guitar, violine and so on will start to vibrate at the set note.This is true even if the force for the vibration is external.You might remember the old school experiment with the two pitch forks on their boxes?Hit one and the other starts to swing too.If you make a resonance box for a vibro speaker with internal or external wire strings at different tensions or lengths you can amplify the sound for the notes that correspond to the strings.Make a relatively large box with some sturdy wires for the frequencies between 60 and 100Hz and you have a really powerful subwoofer from just 20W of input power...I think you get the idea on how to use amplifying strings now ;)My second and total misuse is the xmas tree.If you are a sparky by old trades then you might remember the mechanical frequency meters for generators or other things that required a stable supply.Well, if not than you should know the little wind up toys that play a melody with a drum and tiny forks.Imagine you would replace the glue plate with a rod.Depending on material and length harmonic nodes will form at various places and frequencies.Between those nodes the swing is maximised while the node itself appear to be stationary and without and vibrations at all.For example a steel rod of 1.2m would have a single standing wave at about 1kHz while a copper rod of the same lenght will be much lower in the frequency for a single standing wave.The xmas tree assumes that the rod is of such material that no single standing wave can form below 200Hz and that it won't swing too much at other resonant frequencies.Since aluminium is easy to work with and available in flat and thin bars already it would be my first choice for the branches of the tree.The required length is calculate based on the speed of sound in aluminium - you find online calculators for that.You want the lenght so that you end up with an even fraction of the wavelength you want to "play" with that strip.This allows for the rod to be placed right in the center of the strip where the standing wave movement is zero in the node.Make a lot of thin strips to get a broad frequency response.Placement on the rod can now be crucial.The best option I found so far is using a threaded rod and tapping the holes in the strips.The strips swing quite violently if long and at certain frequencies.And those not in resonance will still transfer their momentum to other strips.This can cause unwanted harmonics.Most evident when a single strips swigns violently at a certain frequencies.Adjusting the angle by turning it is often enough to get out of the overlapping harmonics.With enough strips it then really looks like a tree with flat branches.The sound might not be as loud and impressive as a plastic bottle as the virations are going up and down.But if placed in the right spot it not just looks nice but also makes people wonder where the sound is coming from.Last but not least my yet to be tested hidden speaker system - due to renting restrictions :(If you own a house of the standard frame design then you have plasterboard walls and ceilings.With a large enough surface of the right material, one or two vibro speakers can cover a really wide frequency range at good volume levels.So far I could only do tests in an old wooden window frame but the priciple works the same way between the wooden frames of a wall or ceiling.In my experiments a standard plasterboard sheet needs to be 100 x 100cm to get a more or less decent response for the lower frequencies.Before you rip your walls down use a stud finder and place your vibro speaker on the plasterboard between two studs or beams.I found that two speakers for the lower frequencies and three or four for the higher ones make a good sound.That is per channel and if you have the right size plasterboard sheet in the right place.No point if your left side is further away from the TV than your right.Ideally you replace the entire sheet with the speaker in the right spot on the new sheet but on the back.For obvious reasons this is far from being a perfect solution.But if you plan a full renovation anyway...A way out for older houses is the wooden floorboards.They make excellent resonators for low frequencies.The directional speakers could then still be hidden in picture frames of the right thickness and design.Anyways, I hope I gave you some ideas here ;)

Topic by Downunder35m  


Removing adhesive from vinyl tiles

I am having solid hardwood flooring installed in my first floor of my home. The existing flooring is currently 12x12" vinyl tiles. I am in the process of removing the tiles (using an iron). How do I remove the old adhesive that was used to put the tiles down? Is it necessary to remove even though felt underlayment will be placed under the hardwood? Thanks in advance.

Topic by meemee_0822    |  last reply


is there a way to melt rubber and steel together?

I've been thinking about this for a long time. What I am wanting to accomplish is finding a way to combine steel and rubber together to form a new substance where the two are no longer able to be distinguished from each other.

Question by Jakcavar    |  last reply


hi all, i need the right advice and guidance ...

I want to build a pressure washer engine from the train engine but it is uncertain whether the pump is in accordance with the engine .. engine gasoline / 1298cc / 75bhp / 6000rpm / 108 torque ..

Question by HafizK4  


Halloween Making: Why do we do this to ourselves!? ; )

Closing in on midnight on October 30th, and I found myself in a familiar situation . . .Making last-minute Halloween costumes and props for my kids!Here's a photo of my late-night kitchen table, where I was working on a homemade hover board prop from the "Back to the Future" movies. I paused for a moment to survey the scene and snap a photo, and couldn't help taking note of the silliness of the whole thing. It's midnight. I'm tired. My kids are asleep. And I'm up making this thing. WHY?Why do we do this to ourselves?! - - - - - -I know why I do it, but tell me why you do!Were you up late making stuff for yourself or for your kids? Share your reasoning and thoughts on being a creative Halloweener in the comments below. Be sure to include a photo or two of what you were making!

Topic by seamster    |  last reply


3d delta printer issues

Hi everyone. I need some help regarding the homing of a 3d delta printer, and it's my first attempt to create a 3d printer by scrap. My problem is regarding the homing, when I do the homing 2 out of 3 endstop work properly but 1(always one) doesn't work properly(see video). While the support is hitting the endstop, it moves a little back like the others, but then move up again and doesn't stop 'til I do it manually. there is someone that have some idea to solve the issue? Hope everything is clear enough, otherwise ask me :) Thank you in advance.

Topic by SebastianS217  


Motorized rollerskates, how do i calculate which dc motor to use? Some better than others?

I'm going to try and fulfill one of my childhood dreams; making a pair of electrically powered rollerskates.However i'll need your help if i am to succeed!I have decent knowledge of soldering and the electronic circuit wont really be a problem - i'll wire everything to an arduino duemilanoveSo here's my questions:1. I'll need a motor, is there a specific motor type that is best suited for the purpose?numbers:max loadage: 80kgspeed range: 0-20km/h (~12mph)Something like this, but in rollerskate format: http://www.skateelectric.com/index.php?option=com_content&task;=view&id;=38&Itemid;=45If anyone could point me in the right direction in regards to motor type and motor calculation i'd be really really grateful.I know that voltage is equal to velocity and amperage is equal to torque - and that torque is used as force to drive the wheels under pressure/friction.I've done quite a lot of research already, but i always hit a dead end, nothing here on instructables seem to cover the topic regarding dc engines - and no, i'm not insane enough to power a pair of rollerskates with an angle grinder - i want to have fun, not carve up the pavement and break bones (or spontaniously combust)ps:or this http://www.youtube.com/watch?v=HQzzjBR9EtwI'll do an instructable on this if i get it working, all i need is help with the motor, i'll do the speed regulating myself and all that jazz.

Question by Eirinn    |  last reply


Converting Fake cupboard doors

I just got a free display cabinet with 4 glass doors, but on closer inspection i discovered that the 2 end doors are fake. i want to know if i can cut them out, add hinges and hang them like functional doors.

Question by smikette  


What's the best brand/type of laser cutter for educational purposes?

I've been asked to source some equipment for my new department and I'm looking for a reliable product thats not overly expensive. It would be mainly be used by visual art students and design students. Ideally we would use it to cut board, cardboard, acrylic etc. I can see there are many exciting and interesting objects and artifacts which can be made (as demonstrated in so many instructables!) with this tool. I would be grateful for any advice available. Thanks in anticipation, Lawrence

Question by LAMcGrath    |  last reply


Knex Mp7 PDW

This is my new H&K; MP7 PDW. It features a removable magazine, a foldable front foregrip, iron sights, and it is very sturdy. Hope you liked it and see you next time with another knex gun!

Topic by TheKnexPro    |  last reply


why are the resistors heating up?

So i have 48 UV LEDS and each has a 470 ohm resistor on the anode so in a sense all leds are connected in parallel but it has a resistor on it. when i connect my 12 volt battery with 6500 MA the resistors begin to heat up. is there anyway to prevent them from heating up? or what is it that im doing wrong. ill provide a picture on the way the leds and resistors are connected if you want me to but hopefully what i said gives you an idea on how they are connected.

Question by diabloboy    |  last reply


Magnets in the Microwave, can you do it?

So does anyone know if you can put a magnet in the microwave? Will it cause some nuclear explosion, or rocket me back into time? Or will it just stay on my mug and witness the warming of my beverage?

Topic by Punkergal    |  last reply


Any idea on how to bypass Iboss Webfilter on Mac OS? Challenge!

My computer teacher gave us a challenge: our school used to have filters on most of it's computers, but they were taken down and replaced with something else. As a challenge, our computer teacher re-installed it on some computers and told us to try to get through it. I have had little success, my most promising moment being with a glitch in Firefox, that soon fixed itself and ruined my only gateway. To win the challenge, You have to get onto Facebook, myspace, and twitter, all of which are on the blacklist. Once there, you must post into a specific profile. You must do this three separate times, to illustrate that it can be done more than once. I know it is possible, because two other kids in the class have managed it, but I simply have no idea. The program is Iboss Webfilter by Phantom Technologies, and all of our computers are pretty new Macs. We have access on our computers to Firefox, Safari, Seamonkey, Camino, and Omniweb browsers. All proxy websites are blocked by the webfilter program. All firefox abilities are enabled though. Any and all suggestions or help is appreciated, If we pass the challenge, we get an automatic 100% in the class, because we have probably the coolest computer teacher ever. If anyone can give me a good solution that works, they get a patch!

Topic by ilpug    |  last reply


Knex HK 417

This is my Knex HK 417. It is very nice looking with its flashy side rails and stock. It was a very large gun that held a lot of ammo and shot very well. It was able to shoot passed the length of my house. It also had a removable magazine. I liked building it because it was different than your normal M4 styles.

Topic by Blue Mullet    |  last reply


what is the equation i should use to dilute 50% hydrogen peroxide into lower concentrations? Answered

Hello, i just got some 50% hydrogen peroxide, from my local pharmacy because they were out of 35%, plus for some reason 50% is free. anyways, i want to know whats the equation for finding out how many ml's of water i need to use to dilute a solution toa certain amount, as i want to use the 50% peroxide to make 30% , 22% and 3% peroxide. now ive looked on google and i couldnt find a thing , and if i did by chance come across it, i didnt understand it. what i want to know is how much distilled water will it take to convert 100ml of 50% hydrogen peroxide to the above concentrations, or if possible, could someone please give me the equation for converting any concentraion to any, please! also, whoever answers my question and solved my problem entirely will get a best answr i promise!!!

Question by oldmanbeefjerky    |  last reply


How can I learn the program for a cd drive stepper based arduino plotter?

How can I learn the program for a cd drive stepper based arduino plotter?Help needed.

Question by SHAMSUDHEEN MARAKKAR  


How to wire red led to my toy

Please show me how to wire a red 5mm led to this set up? I want the led to be controlled by on/off switch like the other leds. Please look at the diagram below as to how I have it set up n powered. Please note I was planning on using a 300 ohm resistor for the red led

Question by GNOEL82  


Need help to convert RadioFlyer car.

Hello, I want to convert RadioFlyer Tesla child car to variable acceleration instead of push - full speed. but have no idea how to do this. I have straight hands. If anyone is interested in this project it will be nice to collaborate. Thanks, Eduard

Question by EduardZ  


What kind of rope is best for a ballista? Answered

Would Nylon or Polypropene make a good torsion spring?Or would some kind of metal wire work better? By "better" i mean is able to produce the most force or is able to pack the most force into a 5/8"hole (thats the biggest drill bit i have).

Question by meburnfire    |  last reply