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

Is This Book Still Accurate? Answered

Today I found an electronics textbook, which will be incredibly helpful for me.  If it is still accurate.  The publishing date is 1989, and the title is 'Electronics Principles and Applications Third Edition'.  Would you consider the content to be still accurate since it is on a basic level? Thank you very much, I appreciate it.

Question by StarscreamClone   |  last reply

Information page not accurate?

I noticed on another author's information page (accessed when you double click on stat card) that he had an achievement patch for being in the newsletter. I also noticed that his featured articles were marked with a banner. I had an instructible shown in the 9/30/2010 newsletter and have had one instructible featured (at least at the technology level). How do you get the achievement patch and featured instructibles marked?

Topic by Doug Paradis   |  last reply

Accurate adjustable resistor?

I need a simple, low cost, small device capable of 10 different resistance settings, and must be capable of mechanically reproducing them exactly, on command.  It cannot be a potentiometer, as it is innacurate without some sort of  measurement device (which I cannot use), nor a rotart switch or encoder (too big and expensive, cannot use digital).  Basically, is there some alternative <$2 that will do this.  Again, no digital stuff or measuring position, only going between several set resistance settings (but any incrament thereof is okay).   

Question by jduffy54   |  last reply

What is a good knex sniper? Answered

Ok i want to know  a good knex sniper out here, that is accurate and does not consume too many pieces ( i have a good ammount but not like the killerk stuff etc.)?

Question by Nazgul   |  last reply

Dmm model no. MAS830L not accurate

I bought multi meter on line recently. But it I think cannot measure electronic component accurately. Specification as below 1.model no. MAS830L 2.Brand.MASTECH I measure new battery of 9 V with thus multi meter. But reading is 10.76 V which not correct. So what can I do with this dmm.? 0r how can we calibrate it.

Question by SangpoSangpo   |  last reply

measuring petrol/ethonol accurately

G'day All, If this has been done before, I apologise, but I have not found anything when I have searched. I am a team manager for a team of students who need to design, construct a three wheeled vehicle. The test is a 24 hour "trial" (more like a race ;-) ) We have been competing in a category for "Hybrid Vehicles" which an additional power source to asssist the rider.  In our case it is a 50cc engine using a friction drive arrangement so we can disengage it if required or if we desire.  The reason for this is that we only recieve 3 litres of petrol for the event............  This is my problem.  I have not been able to measure petrol in the tank accurately enough.  Over the last two years I have had one litre left or ran out after 21 hours.    I have been thinking of using a strain gauge or load cell to measure the weight of the tank.  I'm thinking it could be as simple as powering up the load cell with the appropriate voltage, and measuring voltage drop across it, maybe with an added resistor. Or it could be made more complex by using a circuit to drive a number of LED's giving an indication of the fuel in the tank. If anyone outhere has any ideas to do this simply and reliably, I would love to hear from you.  If it is more complex then so be it. Here is a link to the event to give you an idea of what it is about

Topic by coln72   |  last reply

What is the most accurate/inaccurate knex gun on the market

Hello everyone i was wondering what is the most inaccurate and accurate knex gun out there i personly made a pistol that when fired kicks up for the front then fires out the bullet at an inaccurate level. Now your probably wondering "Why the hell would you make an inaccurate pistol?" and Im here to tell you that I did it just for fun Now you can share your most inaccurate and/or accurate knex guns that you and/or somebody else made. Aslo, no hating this is supposed to be fun. So enjoy.

Topic by didexo   |  last reply

How to make a knex gun better

How to make a knex gun better.

Topic by knex maddo   |  last reply

What makes a knex gun accurate?

Yer so what makes a knex gun accurate and I've also noticed that people say "this gun can shoot 10m" which is false because it's more to do with the elastic bands you are using rather than the actual gun.

Topic by smidge147   |  last reply

PIC Internal Clock -- How accurate?

Can I trust a PIC's 4Mhz internal clock to keep accurate time over days of use? Or will I need an external crystal. I'm vary weary of that, as I'm going for a compact design. Thanks for the help.

Topic by zachninme   |  last reply

Hacking a 1-sec accurate timer

Hey all, For my digital SLR camera, I've hacked together a cable relase using a three-way switch. This works a treat, and now it's time to graduate to full automation to help with night time navigation. For this I need to build a timer that keeps a switch in the 'on' position for a certain number of seconds. The timer needs to be accurate to the nearest second, so nothing fancy. Ideally it would be a number pad I can type into the number of seconds. So any ideas? I'm putting together a short instructable to make the cable release. Cheers, Pierre

Topic by eKstreme   |  last reply

Community sections not displaying accurate info

I noticed that several community sections and topic lists are not displaying correct data. I don't want to sound like I'm nit-picking (because I really do like this site), so I hope staff takes this as an effort to improve things and not just as criticism. :) The following sections display incorrect data: ( Community > Forums > Newsletter Archive (shows last post= 1 year ago, but last post was yesterday). Community > Help > Contests (shows 0) Community > Marketplace > Jobs & Internships (shows last post= 6 months ago, but last post was 4 days ago) The following sections do not display topics in the correct order based on most recent; Community > Marketplace > For Sale, Free Stuff, Jobs & Internships, Services and Wanted (only "Kits" is displaying correctly). Community > Help > Bugs and FAQ's Finally, if I may make a suggestion... I have noticed that when a new topic is posted, it does not show up as the "last post" as indicated on the root "community" page. Instead the "last post" is always based on comments. Too often, I think members are missing new topics because they are unaware that they exist if they are basing the activity of a section on the "last post". I think its worth considering that a change be made to reflect the "last post" by activity instead of by comment alone. Thank you for your efforts to make this community a great place to be. As I said, I hope my comments are taken as constructive and not just as criticism. 

Topic by canucksgirl   |  last reply

Equation for accurate bending (kerfing) of plywood

I am planning out my first Instructable. It will be a bent (kerfed) plywood coffee table, There have been a growing number of projects out in the 'makeosphere,' where people are cutting slits or kerfs that go almost completely through a thicker piece of wood, allowing it to be easily bent. I am on a super-tight budget, and cannot afford to ruin my $22 sheet of plywood, so I was hoping that someone might be able to help me with some measurements for cutting the kerf-slits in the plywood. Here is the idea all sketched out. I need help with the measurements that are in bold.  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  PROJECT DESCRIPTION:  Materials: 1x | 4 ft. x 2 ft. 3/4 in birch plywood 2x | 3 ft. 5/8 in threaded metal rods 8x | flat washers 4x | standard nuts 4x | "end nuts"  Steps: On the sheet of plywood, measure in X inches and mark X number of cross cut lines, X inches apart. Measure in 2 inches from each end of the board and draw a line. Measure in 2 inches each each side of the board, and draw another line. Drill out a 5/8 inch hold at all 4 of these crossed lines. Thread a standard nut onto each end of the threaded rod and screw it on 1-2 inches roughly, then slip a flat washer over the threaded rod. Bend each end of the board up to create almost 90 degree angles. Insert each end of the threaded rod into the holes, slip a flat washer over the threaded rod and screw on each of the four "end nuts."  Use the standard nuts, and the end nuts to fine tune the bends into 90 degree angles.  Flip the table over, and enjoy.  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  Stability is more important to me than curve radius. I don't know if spacing cuts close together for a small curve radius is more or less stable than placing the cuts further apart for a larger radius. I've never done this, but I have seen that there is an equation for this. I haven't been able to find the equation actually expressed, I've just heard that there is one. Does anyone know about this area of woodworking/physics?

Topic by Dolmetscher007   |  last reply

easy fast long range accurate paper airplane:the V1

Hey guys,I made a paper airplane thats a variant of the dc3 paper airplane.I call it the V1(V1 does not stand for version 1,it stands for variant 1).Icurrently dont have any pictures or videos of it(I think)but I will soon have pictures or videos of it.

Topic by gardman3 

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

Does a hall sensor need debouncing with arduino? Answered

Hi, I am trying to measure the time it takes for a wheel to rotate using a hall sensor that was pulled out of a old computer fan. Does this sensor need any debounceing to give accurate readings?

Question by David97   |  last reply

How to get an ATtiny to run an accurate clock? Answered

I'm making a clock with an ATtiny and I would like to know how to make it tell accurate time. I'm already pretty sure it would require an external crystal or resonator, but I just don't know the frequency or if there are any code requirements. I'll be programming the chip with an Arduino, if that helps with code. Thanks!

Question by GenAap   |  last reply

What is the best digital caliper for accurate measurement

I have some metal working task, for that reason I need measurement tool. My neighbor friend recommend me to buy digital caliper but I have no idea on it. It would be best if caliper expert user recommend me right caliper. Thanks in advanced.

Question by LinkonL   |  last reply

Having trouble measuring accurate voltage with arduino.

For a week now I’m trying to get very precise voltage readings with no luck so far. I’m using a voltage shunt regulator (LM431) for reference but still. My goal is to read values low as a 1mv change. I’m using a voltage divider to convert 38 volts to 4v (According to my vref). I've read that 10 bit ADC in atmega328 is enough for this job. Is it or am I doing something wrong? Thanks P.S i have made a lot on changes to my circuit so please go over to my new link to get up to date. Ive read all of your feedback and tried to implement it. Thanks a lot for all your answers.  LINK:

Question by faraz ahmed khan   |  last reply

whats the most accurate low piece count sniper ? Answered

Guys im new here but i would just like to know what the most accurate low piece count sniper thanks knex cannon every one who answers in a helpful manner wins them self a free subscribion

Question by knexcannon   |  last reply

Best way to accurately measure capacitance w/ osciloscope?

I am sure there are many ways to measure capacitance w/ an oscilloscope, and one of the annoying things is that some capacitors have different capacitance at different voltages and test frequencies. My original idea was to use the RC time constant and a known resistor, but I think this is probably the least accurate way to do this. Would using a sine wave function generator and figuring out capacitive reactance (and capacitance) be the better method? OR what about measuring resonant frequency of a LC tank circuit? Or some other method I have not mentioned? What's the best?

Question by -max-   |  last reply

How accurate do VGA timing signals have to be?

I'm looking to try to drive a VGA monitor using a PIC 16F690, on a 12MHz clock (3,000,000 operations per second) The most accurate the signal from the PIC can be is 1/3 uS, but the timings given are to 1/100 uS for the 640 X 480 @ 60Hz standard. Overall, each frame does come out to a whole number of cycles, so does the exact duration of each line matter? I've seen a PIC output very basic graphics on a 4MHz clock, so I would expect it to be fairly simple to just light up the display on 12MHz. Alternatively, is the display smart enough to fit whatever is fed into it onto the screen? Thanks for the help.

Question by The Skinnerz 

Accurate Variable Current Sink? Differential Voltage Reference?

Some background: I have recently aquired a few really nice (and really heavy!!!) LAMBDA power supplies, The largest one supplies 24V, and up to 9A, but has annoying foldback current limiting, which causes the output shut off when even a short period overload (like inrush current) is detected. What I want: I would like to modify this power supply to give me (ideally) completly variable 0-15v dual rail voltages & 0-5A adjustable current limit, & I would like this to be controlled with arduino so that I can use a nice LCD display and control the supply remotely with a bluetooth or wifi app, and possibly do some data logging which could come in handy for energy measurements and stuff! My current PSU design: The schematic below is what I've currently built in LTspice. Both the voltage & current regulation work. The voltage across the (+) and (-) inputs of the current error amplifier should be the sum of the voltage drop across the shunt resistor and the voltage drop of a voltage reference, so when the voltage on the shunt resistor exceeds the voltage of that reference, the op amp will start to limit current by reducing the bias voltage on the pass transistor. This V_ref needs to be both variable and accurate, but since this V_ref is a differential voltage between the output of the pass transistor and the input of the error amp, I came up with the clever idea to use a resistor there and a variable constant current sink. That way the constant current through that resistor results in a fixed V_drop across it. With a bit of fudging around with it, I was able to make it work. However, I need to replace that "ideal" current sink with a real one. I tried using the classic NPN-based one, but it wasn't good enough. I then attempted to make the slightly improved version of that current sink with a spare op amp, although this worked, it would stop pulling current once the voltage fell below what was being maintained across the small resistor. The REAL question: Would anyone happen to know how to make a really accurate and variable current sink? Maybe if this is not such a great idea, what other methods can I use to generate a fixed differential voltage?

Question by -max-   |  last reply

123D Design tutorial for technical parts with accurate dimensions?

I'm an engineer with ~7 years of experience using Solidworks (professional CAD software). After hearing about Autodesk 123D Design here on Instructables, I tried to start using it to design and print things with my home 3D printer. However, I'm initially finding it very frustrating to use (more detail on that in a minute) - and I'm not sure if this is just because I'm stuck in my ways with the software I'm used to, or if I'm just trying to use 123D for something it wasn't really intended for. To try and give some concrete examples - I understand that you can create 3D shape primitives (rectangular prisms, cylinders etc) and assign them dimensions when you create them. I also understand that you can create 2D sketch objects and define their dimensions. What I don't find intuitive at all is how you can assign the dimensions of objects relative to each other. For example, say I want to make a 10x10x1mm bracket, with two 2mm diameter circular holes that have their positions on the face defined by the distance from their centers to the edge of the bracket. In a parametric CAD program, that is very easy to do in a 2D sketch and then extrude to a 3D solid. In 123D, I understand that I can create a rectangle primitive and then put holes in it using cylinder primitives - but it seems impossible to define the exact location of those cylinders relative to the edges of the rectangle; also impossible to create a sketch with two circles in it and a dimension defining the distance between their centers. To give another concrete example: at the 4:20 mark in this video (from this Instructable), he draws a circle on top of an existing rectangular part, and then "centers" it by just dragging it around freehand and eyeballing it. Would it be possible to define the center of that circle relative to an edge, corner, or center of that existing rectangle? Or can 123D just not do that? What I'd like to see, if anyone is up for it, is a step-by-step tutorial (preferably in video format) for making some sort of "technical" part where the dimensions matter and it isn't sufficient to just eyeball it and drag things around. e.g. a bracket like this (exact dimensions don't have to be what I drew here, but you get the idea). All of the tutorials I've seen so far - including the official Autodesk ones - seem to just focus on eyeballing it/free-handing dragging parts around.

Topic by Ben Finio   |  last reply

axels weapons from kingdom hearts (ok)

If you play kingdom hearts wich i am a fan of you have to know who axel is from organization 13 here is his weapons.

Topic by combatknex   |  last reply

is there any accurate snipers that i can make that r not powered by compressed air?

Is there any accurate snipers that i can make that r not powered by compressed air? Ive tried glove guns they aren't that good i don't think a spud gun would be accurate either.

Question by    |  last reply

Plans for an alternate method of calculating time accurate to tenth of second ?

This is for a competition it can not use any electrical device and it must literally fit inside a 30cm cube but it can expand in after the starting bell.  If anybody can point me in the direction of plans or kits that would be awesome.

Question by danielsb7676   |  last reply

How to get a bandwidth meter that caclulates accurate bandwidth usage?

I recently got a cable modem and took a limited 2 month plan. The bandwidth is limited so I tried to install two bandwidth meters - the free NetVue and another one called DU Meter which I had used long ago.But the problem is that even when I am not doing any downloading or even browsing, both these meters show that I'm downloading at 5 - 7 kBps, constantly. This way, they show a much higher value than the actual bandwidth usage. I wish to know my daily and  weekly usage, but I cannot know using these two.Can anyone tell me what is the problem with these meters or if I need any other kind of meter for use with cable modem? Very appreciated, if anyone can help. Regards, RS?

Question by rseni   |  last reply

knex keyblade fenroath keeper (fenrir + oathkeeper mixed)

My new keyblade i made up it is a fenrir and an oathkeeper combined

Topic by combatknex   |  last reply

What actually happens inside a Large Hadron accurate is this?

I was wondering, perhaps KelseyMH could enlighten me further, how accurate the information is from this article.  I realize it is slated for the general public so it may not be as detailed as it should be, but barring that, how good a job does it do?  Large Hadron Collider:  how it works

Topic by Goodhart   |  last reply

What mods do my knex X-11 Assult Shotgun need? Answered

I want some ideas on what mods the gun needs so I can make the X-12 version. ****Edit**** If I remade it today, it would look like a G3 dead on. And this was a generic sling gun.

Question by beanieostrich   |  last reply

How can I read accurate analog values on Arduino A2D? Answered

I am running an 8x8 screen from the 5v supply on board an arduino (controlled by the arduino via shift reg's). I am also trying to read an analog value over one of the analog pins. I have noticed however large variations in the analog read value, enough to make it near useless. I get the same problem to a lesser extent without the screen on but still rendering it next to useless. Normal resistors seem to be absolutely fine giving a near constant value, but using photo-transistors produces the error, as does reverse bias LEDs. Any Idea's whats going on or how it may be fixed? p.s. When the screen is on the interference is cyclic, looks like a relatively steady (frequency) sine wave. The rate of the interferences wave seems to vary with how long the display sequence is (basically its display, read, display, read loop). When doing a read I have tried with the screen both on and when the shift regs Output En is low (effectively off) - still getting the cyclic interference. Interference when all that I am doing is analogue reading appears random.

Question by andy   |  last reply

How accurate can a line following robot be? (Laser cutter idea inside)

I have no idea how accurate line following robots can be (and this is what I'd some clarification for), but could a cutting laser be mounted to one? The robot would just follow a black line that you've printed out, and in the process would have also cut out the pattern. If that would work, this would allow you to cut out shapes from a huge canvas size, as well as making quick stencils with a fine line Sharpie.

Topic by olliewagner   |  last reply

measure distance with raspberry pi?

How should i measure 10 meter distance very accurately with raspberry pi ?  if anyone knows any sensor that can measure distance of 10 meter accurately please tell me then i will manage ? thank you.

Question by dharmik123456   |  last reply

I need a good auto loading knex gun with a good mag. I'm hoping that it also doesn't use a ton of parts. Help?

I'm thinking of building the el diablo assault pistol or the tds2. Thanks.

Question by fortheheckofit   |  last reply

ATTINY As A Clock?

Will using time library with an Attiny/45/85/84 ( ) create an accurate clock? I keep on seeing people using these external crystal things. Do I need one? Isn't millis pretty dang accurate? How would I sync the clock with real time?

Topic by HavocRC   |  last reply

How can I accurately scale up an A4 drawing onto a much bigger canvas, without a projector?

I have a few line drawings I want to reproduce but on a much larger scale, but without the whole route of clear plastic + overhead projector (no such tools available). Any ideas?!

Question by    |  last reply

can a smoke detector be modified to be so accurate to detect cigarette smoke in a small room?

In my small 12qm room i wanted a kind of smoke detector to say when the smoke is too much and i should open the window, like when it stinks.. cuz smokers in a smoker room dont smell it anymore.. guess few of u still know that =)would love to hear some answers or suggestions(and no im not looking to modify a already there smoke detector.. ill buy a new one..dont worry)

Question by xgl0baltk   |  last reply

Should I build the Sipriani Rifle 2.0 or the H.A.W.C (highly accurate war crossbow)? Answered

I want something that would be good for shooting at targets from like 50 feet.

Question by Sting Teddy   |  last reply

K'nex sniper rifles

This forum is for K'nex sniper rifles that look good, can shoot atleast 50 ft, and are accurate.

Topic by Smasher555   |  last reply

TJ-SR V1.2 Coming soon!

My Sniper rifle (a good one) is coming out, i hope to post pictures on 18th august, and i will be posting instructions!Pros:Long rangesemi auto 5 shotsA good stockAn accurate sightTrue triggerVery accurateCons:Uses a lot of piecesVery heavyThe mag Jams a bit

Topic by The Jamalam   |  last reply


I need a circuit that will flash a light at fairly accurate regular timed intervals. Perhaps the easiest might be a battery circuit with LEDs, but flashing a mains-powered light would be OK if easier. It is for use as a light metronome, so I need to be able to vary it to between 40 and 200 flashes per minute. Have searched the net: lots of flashing circuits, but none that can be varied in tempo in a reasonably accurate way. Grateful for any thoughts!

Topic by LDW   |  last reply

Testing a Cheap Multimeter

It's been years since I had an expensive meter. These days, I have meters in the $5 to $20 range. Usually they're accurate enough for my purposes, but what if I want to be really certain? Is there a way without a pricey meter to test em?  Perhaps calibrate the meter by checking v  coming out of a v regultor. Would that be accurate? Perhaps the 7805 regulator which is supposed to output 5v.  y?n? M?

Topic by Toga_Dan   |  last reply

CNC Router for Aluminum mold creation? Answered

I know nothing about CNC routers, but I'm curious about aluminum mold fabrication.  Can anyone suggest a good instructable that would be useful in creating a CNC router that would be up for the job.  The aluminum block is 4"x3"x1".  It is completely blank so I need a router to remove the metal to create a mold.  I'm not sure how accurate these things are, but it needs to be very accurate.

Question by Spaceman Spiff   |  last reply

Do cheap pH meters work?

I have seen $10-20 pH meters for testing soil in garden stores, home improvement/hardware stores. I was wondering do these give accurate readings? I am looking for a cheap and accurate way to test pH. Any suggestions even for other ph testing methods are appreciated. Thanks!

Question by rendermatt   |  last reply