Welcome to Instructables

On this page you can find links to some of our most frequently asked questions. What is this site? Instructables is a place that lets you explore, document, and share your creations. How do I post an Instructable? We offer a free and easy online class to coach you through posting your first Instructable or you can just wing it and start a new one today. How do I get help improving my Instructable?Ask the community for help in The Clinic. How does my Instructable get featured? The best way to get your projects featured is by following the Featuring Guidelines. Where can I learn more about contests? Our Contest FAQ has all of the information that you need to know about contests. What contests are launching soon? Check out our list of upcoming contests. Are you on social media? Yes! Follow us on Pinterest, Instagram and Twitter. How do I contact Instructables directly? The best way to contact us is through our Contact Page.

Topic by randofo   |  last reply


Welcome to the Instructables Teachers Hub!

Welcome to the new home for all things Teacher related on Instructables. We hope you'll explore the new features and come back often to find and share projects, inspiration, and classroom resources. As you explore the new Teachers Hub, you'll see it's easy to find projects by subject or grade level and sort them to find all the best and freshest projects.Be sure to spend some time in the new Teacher Forum. It's a great place to connect with fellow teachers and make new friends! You could start by introducing yourself here or finding a topic that interests you and join the conversation there. :)We'll be working to continuously update and support your needs in this new area of the Instructables community, so thank you in advance for your valued feedback and suggestions.

Topic by WeTeachThemSTEM   |  last reply


Site update?

What happened to the instructables site? I can't find anything, no "recent" "featured" "topics" or "question" good luck finding this post. Is it an update or does my computer just hate me?

Topic by liquidhandwash   |  last reply


Down loweing photos

How come when I try to down lowed an Instructables I don't get the Photos?Thanks

Topic by woodie1949 


Login-Credentials BUG: Cookie Mishandling leads to possible website-vulnerability

I posted, Reposted and Re-linked over and over again. Nothing happened, not even a notification "we are on it" from the team.THIS IS A SECURITY ISSUE! People on a no longer logged in PC can see things they arent supposed to!I had this problem in the past sporadically but never saw a pattern till recently:I come to instructables.com, i am already logged in and click on "feed" at the top. After a while an error pops up telling me a Rerouting-error happened. (Umleitungsfehler in German). I noticed, this always happens after the following action-pattern: - I visit instructables.com and log in on computer A and i DONT log out there but only close the browse. - I visit instructables.com on computer B. I am seemingly already signed in from the last visit here on Computer B at instructables.com. - If i now click feed (On Computer B), the error happens. - If i logout and log back in on Computer B, the error is gone on this computer B, even over Firefox-restartsAs far as i undestand, as soon as i log in on computer A, a new login-cookie is created on Computer A and the cookie on Computer B will no longer be valid next time. Now, if i come to instructables with computer B, the cookie somehow still is interpreted valid and logs me in (I appear to be logged in with my avatar visible at the top right). However, if i want to go to my feed, it seems Instructables checks again the cookie and figures out that i have a no longer valid login-cookie on this Computer B due to my login on Computer A and refuses to redirect me to my feed.This gets sorted with Re-Log on Computer B, creating a NEW login-cookie on Computer B and all is well again on Computer B. Now i can play the same game on Computer A with re-log. :)I hope, this error-report helps you guys in pinpointing and fixing an issue with a Login-bug as it seemsAnd Why to hell do i have to define in which channel this belongs and you dont have a channel "website of Instructables"?!? I hope this is not lost in "Circuits" - "Computer" which was the closest i could find to a website-problem... Geez...

Topic by Orngrimm   |  last reply


An Other One

I have made a Plotter using 2 Stepper Motors from CD/DVD Drives.As so many have been done, not sure if the there would be interest on how I made this one.I have made the frame on my 3D printer, and made a circuit so the motors don't get hot enough to fry eggs on.Here is a video of it in action:

Topic by Palingenesis   |  last reply


Ring doorbell n/o quick short button press activate a push and hold buzzer for wharehouse

Existing buzzer in wharehouse need to connect to new ring type doorbell but I need to keep the buzzer tryed a new chime box wired inline, but it's not loud enough was hoping to be able to a circuit or device in line to run the buzzer for ten seconds or so when the short in the normally open bell button was pressed

Topic by john.ward   |  last reply


Giving away a 3-month membership

Who knows? I feel like being nice today :DAnyways, Comment something nice about one of your favorite authors, someone who helped you, etc.That is an entry. One entry per person. On Monday, (tommorow), 3 pm, I'll pick one person to get a premium membership! Also, PLEASE don't enter if you've already gotten a membership. This is meant for people with no memberships only. Good Luck!

Topic by zakbobdop   |  last reply


Call for contest judges

Hi everyone! You might have noticed we're running tons of contests these days.We need judges more than ever to make sure our contests keep running smoothly and fairly!The judging process is fairly simple and normally involves looking at contest finalists and rating them on a scale from 0-9. Judging is typically open Friday afternoon through Monday night, though some of the larger contests have judging that runs for a week. Time spent judging is around 30 minutes to two hours - it all depends on how thorough you are!If it’s not a good time for you to judge when we contact you, no worries. We always try to assign more judges than we need in case something comes up.You can find out more about judging a contest here.Don't worry! Judges are selected after finalists are selected, so volunteering to judge will not affect your chances of being a finalist in any contest you enter.To be eligible to judge, you must have posted at least ONE instructable. Let us know which contest categories you're interested to judge in the comments below: Food Living > includes Home and Craft; so please just say Living if you are interested in either or both of these. Workshop Outdoor Tech PlayNOTES: If you are interested in Halloween we'll pick judges based on categories/entries we get in the contests. Costume > Living Decor > Play, Outdoor, and/or Workshop Prop > Living and/or Play Food > Food Things will depend on what types of finalists we end up with. For example: If we were to have a lot of Tech finalists in Decor, then we would pick judges from that category as well to judge that contest.If you list categories you want to judge, but also say you would judge any, it gets a little confusing. Please try to either pick categories OR say any contest. Thanks for helping us keep the site awesome!

Topic by jessyratfink   |  last reply


What kinds of contests do YOU want to see on Instructables?

Hi everyone! As we're planning contests for the next year, we wanted to get suggestions and feedback on the types of contests we're running. :DIs there a contest we ran years ago you'd like to see again? Any contests you're sick of? A weekly challenge you'd like us to expand on? Do you want the contests to be more specific or more open ended?We're trying to shake things up in contest-land - so any and all suggestions are welcome! I'm especially interested in what types of tech contests you guys would like to see, as well as ideas for food contests. P.S. For anyone wondering about weekly challenges - we're still trying to figure out a way to do it that makes it easy for you guys to enter and easy for the editors here to run. But I promise we are discussing it! :)Have prize suggestions? Check this topic. Want to get a preview of some of our upcoming contests?

Topic by randofo   |  last reply


Grow a plant in my locker?

Currently, this is an idea, and i am simply expanding on it. I had this great idea, mostly as a joke, why not grow a plant in a spare locker? I am currently a high school student that goes to a small school, and have way too much time on my hands. As i was looking at the empty lockers we have from students who left, or even just spares, an idea hit me. Why not put one of these lockers to good use? Why not put a plant inside of it, that can sustain most if not all of itself? Have a gallon of water in there, along with an arduino and a moisture sensor, that would end up watering the plant. I would also have an artificial light source to provide light, preferably LED. The hardest bit is the power. All of this would run off of either a SLA battery or two, or maybe a drill battery. I could swap the battery once every day, which means it would need to go for 24 hours without stopping. That, and the weekends, which would be three full days. I first thought about mushrooms, or other dark growing plants, but i find that boring, lacking a challenge. besides doing this just for jokes, i have also wanted to try out the idea of growing a plant fully indoors without the use of natural sunlight. I have never done this, so please feel free to bombard me with recommendations. Again, this is only an idea. I can only assume it's possible. Also, recommendations on parts and methods would be sweet. Some type of light that can be powered on 12-24v, and run off of a SLA or maybe even a lawnmower battery for minimum of 3 days. Also, plant. I was thinking a tomato plant? Some species that doesn't grow taller than 2.5ft? Anyway, that's the idea. If you guys could help with ideas, provide recommendations, or point me in the correct direction, that'd be sweet. Last note, i would like to keep this cheap. I am not going for some extreme garden or anything. Just a single plant, in a semi-self sustaining locker.

Topic by RocketPenguin   |  last reply


Can anyone make this Crossy Road Arcade?

Anyone has any source for DIY this Crossy Road Arcade? I did lots of research about this, but dont see any information about it. Looks like there is arcade version of this game and can not be found on internet....There is only one button for jumping, no joystick is needed.Can anyone DIY this arcade and share the instruction please?Thanks

Topic by rootloop   |  last reply


# of published Instructables is wrong in Profile-Overview

As you can see, in the top right corner, it sells me: 1 Instructable published.If i check, i in reality have 2 (Main part of the webiste).Buggy buggy...

Topic by Orngrimm   |  last reply


What kind of repetitive elements can you use on a surface with a gluing material inbetween to decorate it and look luxurious?

What kind of materials/repetitive elements/items can you use on a surface with a gluing material inbetween to decorate it and look luxurious?Check my pinterest folder, I want to make a parametric/curved wall ( https://i.pinimg.com/564x/34/e4/04/34e4045e39debc... ) and put plaster on it and some bounding agent to attach the repetitive elements https://i.pinimg.com/564x/34/e4/04/34e4045e39debc... what can I use?

Topic by DIAGONALLIS   |  last reply


Knitting Machines?

I'm trying to knit a sweater-vest that has a two color repeating design. I'd like to use a knitting machine because I am trying to recreate a sweater-vest from a movie, and it looks like using a knitting machine is the best way to go. I know next to nothing about knitting machines, but I've seen them on eBay and Craigslist for pretty cheap (Like, less than $50.) but I have no idea what I need.  What's a good, cheap, knitting machine? Also, what's the deal with punch cards? I don't really know what they're for. Can someone explain this all to me? Thanks so much, I can't wait to see what responses I get. You guys are awesome.

Topic by Super Cameraman   |  last reply


Deactivated Bone Growth Stimulator

I have a CMF bone growth stimulator that no longer works. These devices are set to die after so many uses. Does anyone have any ideas on how to reactivate these units? Or, hacking these things for another purpose?

Topic by wmlaveck   |  last reply


Can't Save my Instructable!

Hey all! I'm having a problem saving my Instructable, every time I save or it autosaves, it gives me an error like the one in the screenshot attached. It's only started giving that error recently, before which it was saving fine. I'd really appreciate some help! I'm using Google Chrome Version 45.0.2454.101 m on Windows 10 Thanks!

Topic by Satyavrat   |  last reply


3D Viewer

Instructables Team - I don't know when it was changed but the "View in 3D" upgrade works very well. I especially like the section analysis and exploded views.Makers - if you are like me and enjoy showing your work in CAD, please consider dropping STP/STEP files into your instructable.

Topic by mtairymd   |  last reply


Help with wooden bathroom sink cabinet top surface

Hi, I have just relocated to Switzerland and live in a rented accommodation. The master bathroom has double sink wooden cabinets. Unfortunately, the top surface of the cabinets is not covered by glass, marble, or quartz. The sinks sit on the surface (solid wood). No matter how careful someone might be while hand washing etc., you can't get away without splashing. Major stress if you think that you might need to pay for replacement of the cabinets at the end of tenancy.How could I protect the area? Many thanks PS. (link) Master Bathroom sink top pictures

Topic by ADoZ   |  last reply


High School Teachers

Do you teach 9th-12th grade? If so, say hello and connect with other High School educators. Feel free to share where you are from, what grade level(s) and subjects you teach, and any exciting projects you did with your students this year or fun plans you have for your classes next year. :)

Topic by WeTeachThemSTEM   |  last reply


Wanted: Looking for EMPTY Nitrous Oxide Canisters

Looking for EMPTY, only empty, Nitrous Oxide canisters.. the small kind, for like airguns or whipped cream.

Topic by laminterious   |  last reply


Treadmill control console

I need information about treadmills control consoles, how they interact with the lower dc controller and why they are not interchangeable with others from another treadmill as they perform the same job?. Thanks.

Topic by abuyaseen   |  last reply


Herbst Appliance

-update-cant believe the attention this has got. either way i got my braces off...in august of 2008. Wednesday before school started. Finally.straight teeth finally, and i can eat! so great.either way it still took like 5 or 6 years, too long.Im just wearing an invisible retainer(behind my teeth, its glued in, its just a wire). Cant even feel it.Just think- if you have braces- how good it will feel when you get them off...OK, I have braces, meant to correct the spaces that were in between my teeth, and also, to move my lower jaw forward. I've had them for...5 YEARS! Needless to say, they JUST finished closing most of the gaps(again, after 5 years), and are working on moving my jaw forward. So, like almost every person I see with braces (well, some), I got rubber bands. I actually had a choice between them and the Herbst appliance. I picked the herbst-y thing, but they didn't have a part...so, blah blah blah, long story short, I got rubberbands until the part came in. So the part came in today, and I went for them to put it on, and after about an extremely boring hour, they were on. Anyway, It wasn't until then that I realized what (Insert bad word(s) here) things these were. I can't eat ( more specifically- chew), talk (clearly), or EVEN FULLY CLOSE MY MOUTH!.i hate them...................SO... ...on a lighter note, does anyone here have/had that herbst thing before?Update- I got them off, and I'm wearing rubber-bands now.

Topic by John Smith   |  last reply


Don't keep rats as pet !

When my brother decided to travel around the country, he has been forced to leave the white rat he kept as pet ... and I've been forced to adopt this little animal.Rats as pets quickly become cute, funny, and show a personality that make them even more endearing ... In other words, "la souris" (the mouse), as I renamed it because I was unable to remember the name my bro gave her formerly, quickly found her place in my home and my life.So, happy end ??No !No, because rats pets quickly develop lot of weird diseases :- dermatitis - mange- bumble feet- cysts- tumors- etc- and various infections and self-injuries because the rat scratches or bites itself because of one or several of the above diseases.The health and the life of your rat will quickly become a nightmare, and, if like me, you tend to consider your pets like full members of your family, your rat pet will become a great source of worries ... and if you're not cruel, you'll be forced to give an end to its agony. Because that's a real slow and cruel agony.Most people who adopt a rat as pet seems not to be aware of all the problems this little animal will have, neither how expensive it will be to look after it.The internet is full of sites dedicated to the diseases of rats pet. My advice : If you love pets, don't adopt or give a rat as pet !20080225 update :Despite what I said, if you still want to adopt a rat, then, you should better document yourself a lot before commitment.Member Please wrote a tiny instructable about How to take care of a rat the right way. She is a breeder, so you could ask her as much questions as you need.20080226 update :She also wrote two other very useful articles :avoid bad diseases for your pet ratfun games for your pet rat

Topic by chooseausername   |  last reply


Looking for a Fun Creative Project for Adults with Little to No Experience

I run a non profit teaching kids computer science concepts. As a fund raiser idea I was considering hosting an adult class at our local makerspace. I am looking for a kind of nerdy, somewhat inexpensive projects that adults will enjoy making as well as displaying in their home or office. With kids we do coding, make games, light LEDs with arduinos, make Raspeberry Pi cameras, and play around with paper circuits and homemade hex bugs. Does anyone have any adult ideas that may be fun? (Also, we are considering having a local brewery bring beer) I am open for more kids projects too, if you have any.

Topic by jkahle   |  last reply


​Teacher/Edu Focused Contests

Hey, teacher community! Did you know we are running three exciting teacher/edu focused contests right now? And we are launching more each month! :)The Classroom Science Contest is ending July, 29th and the Grand Prize is a $1000 Amazon Gift Card.We're also running a DIY Summer Camp Contest which ends August 26th and The Growing Beyond Earth Maker Contest which ends February 2nd.As we're planning more education focused contests, we would love to get your suggestions and feedback for the types of contests and prizes you would like to see.Is there a contest for a specific subject or topic you'd like to see? Are there prizes that would help meet a need in your classroom?We want the teacher contests to be a fun way to show off what you're doing in the classroom and provide you with prizes that help you continue to do all the amazing stuff you do, so let us know. :DP.S. Here's a preview of some of our upcoming contests.

Topic by WeTeachThemSTEM   |  last reply


List of Upcoming Contests (updated 6/4/19)

Hello everyone! Below is a partial list of the 2019 contest calendar. Keep in mind that this list is subject to change and contests will continue to be added throughout the year. The contests below are already in planning, and I've left off ones that we're still trying to decide on. The months indicate when the contests will be launching. All contests will launch near the beginning of each month. Keep in mind that the list below is not set in stone. All contests and dates are subject to change!JulyPlanter Challenge Design and create a planter or potPaint Challenge Painting tutorials, tips and tricks, using paint to refresh old itemsBBQ Challenge Share your best grilling recipes ands favorite sidesSew Tough Challenge Sewing projects, but extra rugged and practicalGame ContestOpen to all games and gaming inspired projects: cosplay, props, tabletop games, arcade machines, controller mods, etc.DIY Summer Camp ContestPitch a tent, learn archery, build a boat, get campyStone, Concrete & Cement ContestGet stuck between a rock and a hard place and make cool stuffAugustFlying ChallengeIf your project flies, we want to see itSpicy ChallengeFeeling hot, hot, hot... when it comes to these recipesClassroom Organization ChallengeShow us your favorite solutions to tame the craft and work supply madnessMake it Move ContestAny project that moves is eligibleMetal ContestUse metal in your project - head banging optionalIndoor Lighting ContestWe love lampTeacher ContestTeach us your ways, oh educators!SeptemberMotor Vehicle ContestCars, trucks, vans, motorcycles... you get the ideaMaps ChallengeMake cartography great againKitchen Skills ChallengeShare your kitchen knowledgeCNC ContestBuild a project using a CNCMultidiscipline ContestOpen to projects that combine two or more disciplines, like woodworking AND sewingSkateboarding ContestBuild a board, share tricks, wax every ledgeHalloween ContestCostumes, props, decorations, food and moreOctoberAfter School ChallengeAfter school projects and activities Book Character Costume ChallengeLet your imagination run wild and bring your favorite book characters to lifeCandy ChallengeSugar and spice and everything niceArt Skills ChallengeDrawing, painting, sculpting, animation and moreMade with Math ContestCombine math with makingRobots ContestMake yourself a robotic friendNovemberMeal Prep ChallengeGet a gold star in being an adult and teach us how to meal prepFashion ContestIt's called fashion sweetie, look it upInvention ContestSolve everyday problems by creating something newAssistive Tech ContestUse technology to make life easierHome Decor ContestRefresh and restyle the DIY wayReuse ContestWork with what you've got instead of buying newDecemberPCB Badge ChallengeCreate custom PCB badges using EagleCrazy 4 Coding ChallengeShare fun coding projectsCookies ChallengeC is for cookie, and cookie is for meFiber Arts ChallengeThe challenge for all textile arts: weaving, crochet, embroidery, sewing, etc.Instrument ContestMake some noiseMad Science Fair ContestOpen to all science fair projects and experimentsShelving ContestGet creative with shelvingMake it Glow ContestAdd LEDs to all the things! *All contests and dates are subject to change. Please leave suggestions for prizes here. You can also leave suggestions about contests here. Have a contest question? Check the Contest FAQ!

Topic by randofo   |  last reply


Prize suggestions and feedback needed! What would YOU like to win?

Hi everyone! Here at HQ we're always planning contests, but sometimes we run out of prize ideas. :D I would love to hear any and all suggestions for products you guys would like to win! I'd also love to hear feedback about prizes we've offered this year - what did you like? What didn't you like? Do you prefer getting a shiny new electronic toy or a prize pack more suited to the theme of the contest? Have a suggestion for a contest theme? Check out this topic!

Topic by randofo   |  last reply


Very Frustrated - Instructable Won't Publish!?!

Okay, so I'm a professor and I have a nice project to publish.  For a first time user of this site, I'm thoroughly frustrated with the lack of detailed feedback when something is wrong.  I would fix it if it would tell me.  Usually I just walk away thinking that the thing is simply not worth the time, but the reputation of this site gives me repose to try to find out why. My instructable was saved and shows up in my drafts.  Great. I hit publish and it goes to a page to request keywords and category.  Great. I put a minimum of 2 keywords and select a category.  Great. I press "yes, publish my instructable" and the page refreshes, clearing everything I've entered. After doing this ten times with no other results or feedback of what the problem is, I find myself writing this topic in hopes somebody knows why.  Whatever the answer is to this dilemma, its kind of ironic that the instructable site is so lacking in basic feedback when there is a problem.. Oh well, I hope you understand my frustration.

Topic by Pr0f Most   |  last reply


HELP: Measuring power density from cellphone tower.

I am working on a project to measure the power density from cell tower. Most projects I saw involve expensive antenna and also a spectrum analyser which is too costly. I came across showing ppl fabricating a target single band microstrip passing through a RF Detector circuit. I think chip like AD8318 could handle it?? But how am I gonna filter if were to use an antenna with range of 200MHz to 2GHz eg. (https://www.sparkfun.com/products/8347) to measure a specific GSM band like 900/1800 MHz from the cell tower? I need help on the filtering and RF detector circuit part!!The closest resemblance to my proposed system: https://www.favoriot.com/category/how-to/

Topic by StudD   |  last reply


Control Amperage

Hiyas, I was wondering if you could point me in the right direction. I was wanting to build or buy something I could control Amp input. The system would be 12 -14 v dc and I want to be able to limit the input to say... 25 - 30 amps. So if a system would naturally draw more amps I want to be able to control the system be limiting the amp input...if that is making any sense. Got any thoughts ??? tks Huchleberry

Topic by huchleberry   |  last reply


Need help making pop up speakers

So im trying to make a pair of popup speakers for my desk. I dont even mind it being pop up empty rectangular boxes (platforms) in which i can put in some portable Bluetooth speakers. I have attached a picture of a popup socket. Im not sure how it works though. I know you can use linear actuators but im not sure that will work or maybe i havent found the right ones. please if someone could help me

Topic by mmathavan   |  last reply


HOW TO SETUP 5 UNIT OF 3 PHASE WIND TURBINE 2KW 48V TO 10KW 240V HOME

Hai... I need some solution... I'm not a electrical engineering... so, there are 5 unit of 3 phase wind turbine, with rate output up to 2Kw, 48V each... and I need to produce current load for home about 7Kw to 9Kw, 240V,,, so, how to wiring from 5 unit of wind turbine to home current...sorry for my english and thank you...

Topic by zeak1975   |  last reply


Cloning the famous ARA-2000 antenna for SDR use

Several years ago the company behind the original ARA-2000 antenna, Dressler Hochfrequenztechnik, closed.The ARA series of antennas, like many other products by this company never got a patent, instead it was trusted that no one would bother to replicate it.A bit like the Swiss Army knife, many tried to copy it, none really managed to match the original quality.There is quite a bit of hacking still going on for this antenna, most projects though seem to be abandoned at the time of writing this.I am currently trying to figure out how to create an entire clone that everyone who knows how to properly use a soldering iron can build.There is a lot to consider here...The active element is of quite unusual shape and needs to be wound around a cylinder of a pretty accurate diameter.My initial tests showed that for example aluminium foil with some unavoidable wrinkles already has a negative effect.And a change in diameter of just 2mm means the entire antenna only performs badly for the entire band.This part is thankfully already solved to my satisfaction using thin copper sheets and some stiff plastic sheet.Quite a pain though is the MMIC part - the amplifier that makes the antenna active.There is a ton of MMIC blobs available, either solo or as a ready to go amplifier.Downside is that without really knowing any characteristics of the original is comes down to guesswork.And as most of the cheap SDR dongles won't provide a BIAS TEE I will opt for an external power supply for the amp.I might provide the option for a inline use a bit later though.Why clone the ARA-2000 antenna?For starters you need to forget the mythical stories you might have heard about this antenna."Picks up even the weakest signals!", "Totally linear over the entire bandwidth" and so on...Without the amplifier the antenna is actually not even average in therms of reception performance.My initial tests with a network analyser showed that the anteanna actually is behaving really weird (without the amp!).Although this first bit needs further testing, it seems that most, if not all of the work in the 1.5-2GHz range is done by just the straight connecting strup going from the amp, or in my test case the coax, to the wrapped antenna part.For anything in the more interesting frequency bands it seems that the antenna is not using anything like a discone, whip or ground plane antenna.Instead the 3rd harmonics of a given frequency provide the max power output from the antenna but it arrives at the cable at the right frequency.Especially in the lower frequencies, below 200MHz there is also quite some phase shifting happening.As a passive antenna it seems to be almost impossible to find a frequency to transmit on without using some matching trickery first.But when it comes to size or looks, the ARA outperforms everything you can think of unless you want to constantly adjust the length of your whip antenna.And if you check what is available in real (user) data in terms of noise and signal quality than most other antenna types are far worse.The design provides a wide frequency range with very little noise, almost like a build in filter.Considering that mostly harmonic frequencies are used not that surprising.Getting hooked on SDR means you start little and then you want more and more.Unless you really need the low frequency HAM bands below 50MHz the ARA is a good choice that just makes sense.What is quite surprising in the original is the total lack of protection for strong signals.Sure, we might never need a lightning arrestor because all is enclosed in plastic and has little attraction lightning, but someone hittiing the transmit button close by....I will have to do some more checks to determine whether or not more protection is required.What is the problem with amplifier?For starters, no one really knows what was used in the original - they all just guess based on how well the real design matches some datasheet.Means whatever was used might as well be a custom made solution.I checked a few datasheets for MMIC amps but could not find any useful reference to the handling of things like negative gain, phase shift or a constantly changing impedance.Some however state that a 50 or 75Ohm signal is provided at the output.If I interpret that correctly than those MMIC's not only amplify but also do some matching.In most cases you won't need an amp that works outside what the antenna can provide.Problem is that I don't like regretting things later on ;)So IMHO it would be best to use a wideband MMIC covering all from about 1MHz to a few GHz.Additional filters can then cut off what is not required or where the antenna starts to fail.What is clear by the original design is that the cable shield acts as a ground and most likely also has a balancing function.It would make sense to add a ferrite trap close the the receiver to filter out what the cable might otherwise mess up.Can the frequency range be lowered to get even the low HAM bands?The answer is YES and NO.It is not a big problem to extend the cone shape and then hope to come much lower.Issue with this is the helical, long periodic design.As basically only the 3rd harmonics are used for all interesting frequencies any ARA type antenna going much lower would end to be really long.You can't just make it longer!One thing is to have a full and even number of turns.The original only had two, three turns is bad, four means the entire antenna is slightly longer than your average downpipe for your roof gutters....Other, seemingly logical alternative would be to stick to two turns and to increase the diameter.Apart from the size problem here we would also change the shape of the foil quite a bit and I have not done enough tests with that to provide a conclusion.Are there alternative design options?As it turns out copper pipe is available in 80mm diameters for the use in chimneys as well as downpipes.With a proper machine it would be pretty straight forward to remove what is not used as the active element.Milling a pipe or rod is these days a common thing in many good workshops.But on a hobby level and low budget....One of the best options for cheap test antennas of this design is to use tinting foil - the cheapest you can find ;)Just read the lable and make sure it does not use a metalised film.If it has no UV protection and no tinit at all it is best but hard to find.A little less stiff is the stuff to cover school books or cupboards.Vinyl is bad though!If you look for copper foil in the cheap online places you mostly find the suff used for shielding in rolls of 200x1000mm.Unless you have a really sharp knife or really suitable sissors this stuff is a pain to cut as the glue tends to stick very good to whatever you use to cut through.Don't ever try one of these blade type cutters for paper and pictures unless you put a slight oil film on all cutting surfaces first....In some hobby shops you can get copper foil without any glue in different thicknesses - this stuff is the prefered option.Not only cheaper than the China rolls with glue but you invest a bit more and get a thickness that does not wrinkle right away when working with it ;)Cheap, steel downpipe and cutters or nibblers?I though about and I tried - and I failed LOLUnless you use a pin type nibbler and custom made rig the result is quite bad - at least mine was.What works though is to use thin aluminium sheets, cut them and then bend them around a suitable template.But I ran out of old laminated sings to salvage and the duble sided ones I have left are too much work.What comes next?Well, I have a few rolls of copper sheets coming next month, the cheap glue covered type.This time however I will leave the plastic cover on and use tape to secure the foil to the pipe.A two-stage amp with external power supply is coming too so I can do some more tests in this area.For the time being I will opt for some 3D printed end caps but with a bit of luck can find something easier next time I have time to waste in the hardware store.Excluding cable and a cheap USB or 12V power supply, the current costs of building the anteanna are around $40US.About half of that if you don't cennectors and attach the coax directly.Another experiement I am working on is to use copper tape, 12mm wide, to create the antenna in a semi-fractal style.I am hoping this will provide a high enough gain so the antenna is usable without an amplifier.Right now the biggest issue is to find a really SDR suitable way to deal with strong signal close by.I will keep you update here when I start with the new antenna and upload some pics along the was of building it.

Topic by Downunder35m   |  last reply


SDR antenna - 50 or 75Ohm cable?

Once you get going with your new SDR dongle you soon realise that it is little fun with the supplied antenna - if it came with one...Local stations, police (unencrypted) and so on is all fine with the short antennas.But if you want to get weaker stations or even track some satellites you are as lost as trying to get anything in the 160m band on your screen.Obvious way out is to get an external antenna.Depending on your needs and layout at home you might be lucky to find a ready to go option at some cost.In most cases though you will need more than the 3-5m that come with the usual antennas for car use.And not all base station antennas come with enough cable - keep in mind that hieght above ground and no obstructions close by count...With RG58 cable already being quite expensive a lot people consider the cheap 75Ohm TV cable as an alternative...Can we use 75Ohm antenna cable for our SDR needs?Of course we can!We only need to make sure that at the antenna end AND the receiver end the cable acts and appears like a 50Ohm cable.Especially if you need a really long cable in range of over 20m the TV cable shines with less loss that can't be ignored.Let me try to explain it the simple way first:You TV needs 75Ohm but the good old dipole antenna provides 300Ohm.The so called BALUN that connects the actual antenna with cable matches the antenna to the required 75Ohm impedance for the cable and TV.Like the TV, we don't transmit anything, so we don't have to care about what happens if power would go to the antenna - it is not a radio in the common sense, we just listen ;)There are many options available to match any impedance to any other but in our case a lenght of coax pairs is all that is needed.1/12 of the wavelength for the 75 and 50Ohm cable and we have a match.But.....You are right this simple option does not really work if you want to listen to a lot of different frequencies.What works fine for the TV also works fine on both ends!I assume you use an antenna for the common 50Ohm system and a standard 50Ohm SDR module or receiver.Two simple transformers will do the trick just fine and allow us to use cheap 75Ohm TV cable.The one on the antenna end provides 50Ohm for the antenna and 75Ohm for the cable.For the receiver the transformer is the same type but connected in reverse.You can look up how to make one with a simple ferrite torioid core and wire or coax but also order them from your favourite Chinese seller in the usual online markets.Add an antenna switch and you can use multiple antennas optimised for the frequency in question with dirt cheap TV cable.Just make sure to put the balun in a metal enclosure that is connected to the braid of the coax on both ends.

Topic by Downunder35m 


The Clinic // Get help with your Instructables!

Hello and welcome to the newest version of The Clinic! If you have an instructable that's not getting the attention you think it deserves, post it in the comments below for honest feedback and suggestions to improve it from fellow authors and Instructables staff. We want to help you create the best instructables you can! Curious about the basics of creating an instructable? Check out my FREE How to Write an Instructable Class! You can also read through our Featuring Checklist. Posting a great instructable has many benefits, including:More viewsMore comments and followersHaving your instructable Featured on the site Having your instructable featured on our social media accounts (Facebook, Instagram, Twitter, Pinterest)Better chance to win contests Driving traffic to your websiteP.S. While I know the goal for any instructable is to get Featured, it's not the end goal here! We're sure to hand out features, but please keep in mind not every instructable is feature-worthy. Even the most popular authors have unfeatured instructables! Don't let it get you down - you're still amazing! :D

Topic by jessyratfink   |  last reply


Help! -I need a timed cigarette dispenser - seriously

Have tried everything to give up smoking and failed, so a neighbor offered to give me 1 cigarette every 4 hours so I can cut back. Now she is going out of town and I really need a machine to do this job. Can anyone come up with a relatively inexpensive machine that can be built by an amateur like me? I would be grateful for any help.

Topic by diane4m   |  last reply


Pedal Power LED lit night soccer!

Hello,My school entered into a "pedal power video" competition, the challenge was to make a video showing how to use alternative sources of energy, so my school had a soccer game at night where we lit the field up using pedal power and generators. This was done by attaching a belt to the back wheel of a bike and hooking it up to a treadmill motor working in reverse for power. Enjoy!thanksiosman

Topic by iosman123   |  last reply


Principles of Laser cutting

I have being repairing all forms of cutting & welding machines for some years. In my experience for example Plasma cutters work on a principle of momentous arc. This is formed by a High frequency arc it only gives you 30 milliseconds to start your current flow. Air is required to force this arc out of the plasma cutting head. Ok got your attention now getting back to a laser cutter it also uses air to force out cutting light to cut or engrave. so looking for more under standing to work on a problem.

Topic by Keith MichaelD   |  last reply


Q: can i power a (9v-battery) multitester with 8 or 10v?

Hi, i´m living in a mountain-cabin with a small solar-kit (12v battery, 6 x 2v cells).i want to buy some multi-tester (which normally uses a 9v battery).i hate to buy batteries (and not just becauce i am a cheap fukc - might actually cost about a bit less than the tester itself, go figure, beauty/beast of capitalism)since i got anything from 2-4-6-8-10-12v here (for free - thank you sun): can i run the tester with 1 volt more or less? (or does all hell break loose .. which i´m actually kinda fond of)bowing

Topic by la xerra   |  last reply


leg and arm weights

Will someone write up the plans for a HEAVY-DUTY ankle and wrist weight. I have been searching online for a company that will make custom weighted wrist and ankle weights but there aren't any. I'm wanting to make a 50 lb for the arms and 100 lb for the legs. I'm thinking along the lines of several iron or lead bars strapped together with a nylon fiber or other strong material. I've only ever done projects in high-school, where materials were provided, so I don't really know where to get the materials needed. Please help.

Topic by dhill16   |  last reply


Recent Feed Page

We have heard your feedback loud and clear, and we will be bringing back an easy way to see all recently published instructables. This requires some dev time because we changed things under the hood and need to do a little work to re-create this page. We hope to have it back shortly.We appreciate your patience as we continue refining the site after this release.Update:The recent feed has been released and can be found at this link:https://www.instructables.com/feed/recent/You can also find a link to it on your feed page.

Topic by randofo   |  last reply


what to do with a 50,000 volt Tesla coil?!

I just got a 50,000 volt Tesla coil (Oudin coil) for Christmas. I dont have a clue what i could use it for, i need inspiration. My uncle likes to surprise me with semi random things so other than shocking metal tables i just dont know what to do with it. ---from teachersource.com (where he ordered it)While more accurately called an Oudin Coil, these are commonly referred to as a hand-held "Tesla Coil." This coil is self-contained in a heavy duty Bakelite case which forms a convenient handle. The spark is adjustable from 10,000 to 50,000 volts at frequencies of approximately 1/2 megahertz. The high frequency spark produced is about 1" long and can be used for a wide array of applications. An instrument like this is intended for intermittent use only and must be turned off after 10 minutes of use. The electrode furnished is approximately 2" long and the instrument is furnished with an intensity adjusting knob. For 115v, 50/60 Hz. An improved SAFETY FEATURE is the ON/OFF momentary switch which is in the handle. This makes our Oudin Coil extra safe for classroom use. (Runs on standard North American line current, 110 volts 60 Hz)

Topic by i make shooting things   |  last reply


Make use of iCamera 1000 units?

I have 3 "iCamera 1000" camera units laying around. I do not have the rest of the security system they are designed to function with, but there has to be some way to make use of them and have some fun. I have lots of cat 6 cable and RJ45 connectors to custom make a cable if anyone has the expertise to figure out how to make use of these. Before posting here, I searched and searched here and on Google but only found information regarding the "normal" application of these cameras..... I was hoping for something more outside the box which is why I am here. I included a front/back picture. Thanks for any ideas!!

Topic by PigWhistle   |  last reply


How Do You Make a Clock Silent?

I've tried tinkering, but it never seems to work. Is there a way to make an analog clock silent (or at least quieter), without actually turning it off (the idiot's answer to everything)? I recently had to retire my old bedside clock, and so I bought a cheap-o one at Wal-Mart for about 5 dollars...and it is the loudest thing I've ever heard. Will someone please enlighten me?

Topic by KnittingFreak   |  last reply


Suggestions for this post

Hello, i recently posted this instructable, please suggest tips to get better at this post since it wasn't featured and how to avoid those mistakes in future,thank you!

Topic by MissionCritical   |  last reply


Removing Broken Pin from an RCA Jack

I recieved a free, working TV the other day. The only problem with it was the pin from an RCA video cable had broken off inside the socket. I didn't want to spend money on an RF modulator for my DVD Player, so I figured out a pretty solid way of getting the pin out. 1.) Find a needle 2.) On a hard surface, bend the very tip of the needle slightly so that it forms a tiny barb. 3.) heat the tip of the needle with a lighter until it glows red hot. 4.) stick the needle into the plastic core of the broken RCA pin 5.) wait a few seconds for it to cool 6.) pull the needle out, and the broken tip should follow!

Topic by spenjmn   |  last reply


Not able to open drafts.

Hi Team,I am unable to open drafts. Clicking on profile pic, its shows drafts, but nothing gets showed up once I click on it.Please help resolving this.Regards,Vineet

Topic by IoT Cloud Guru   |  last reply


Ever heard of Ceramicrete, MgO cement, Magnesium cement

Has anyone ever worked with MgO cement?  Where can buy it in US? MgO replaces the Ca found in portland cement. MgO cement makes a concrete that will incorporate cellulose and other organics into the crystalline structure. absorbs CO2 instead of generating it, is an order of magnitude stronger than portland, does not require wetting, and cures in minutes. So basically, you can take some burlap or old blanket and paint this stuff on, then fill the void with straw and cement and make super strong, light and thin structures. I have looked for it locally but it does not seem to be available to consumers in the US, probably because of the lack of sheep crap which is the typical source of Mg. It is amazing stuff. This is pretty much the only article I could find about the stuff: http://greenhomebuilding.com/articles/ceramicrete.htm

Topic by bsims1   |  last reply


Methods for Powering 8 LEDs?

Hey Guys - My daughter has a small Little Tikes car which I'm adding 8 LEDs (3 per headlight & 1 per taillight) to. Each LED is a 2v 20ma. I've already started, but hit a snag. For testing the LEDs, I used a 9v battery with a 330ohm resistor on positive. This lit individual LEDs as well as 3 LEDs in parallel. My plan was to wire them all in sequentially then figure out what was needed resistor wise when done - bad decision. I have almost everything installed except power and now stuck as to what do do. Having 8 LEDs which are 2V / 20ma, exceeds the voltage a 9V battery can produce. Afraid to try connecting the 8 directly to 9V as don't want to risk burning them out. Just wanted to post to see what my best option would be - especially one where I wouldn't have to rewire everything again in parallel if at all possible. Thanks!

Topic by bzowk   |  last reply