Linear Magnetic Field

I am stuck in my research,please tell me a way to make a linear electromagnetic field,other than making an outer core for it please help me

Topic by ajose4 5 years ago  |  last reply 5 years ago

remote linear actuator

   Hey everyone. I have a question about a  linear actuator that I'm putting on my sawmill to control the throttle. On a sawmill you either need to be full throttle or idle. I've already got the actuator mounted and it works great. Now I need a controller for it. I've got a keyless remote from a auto parts store that I would like to use. I also would like to have a hard wired button. The kicker is that I would like to be able to push a button on the remote or the wired button and the actuator go all the way out. And then push the same button and it come all the way in. The actuator has built in limit switches so it will stop on its on either all the way out or in. This may not be feasible for me to do but I was just thinking by using relays it may be. If I can't use just the one button then I'll have to use two. There should be no need for a stop button since the actuator has a limit switch at both ends. Thanks

Question by papermaker007 7 years ago  |  last reply 7 years ago

How does a Linear Motor work?

Spell it out for me, i'm having a hard time understanding it.

Question by lutziepv08 9 years ago  |  last reply 9 years ago

Possible to use a single foot pedal switch to activate a linear actuator?

I acquired this mechanism which I would like to modify for ease of use. The original set up uses a linear actuator and a 3 way toggle switch. The linear actuator comes with built in limit switches. The 3-way toggle is not practical as my hands are fully utilised on the work bench. I would like to modify the set-up so that I can use a single foot pedal switch to get this motion. One step on the foot switch and the linear actuator extends to its maximum length. Then another step on the same foot switch and the linear actuator retracts to its maximum. Any help with the circuitry and parts will be greatly appreciated. Thanks in advance. ROY

Question by anslemroy 3 years ago  |  last reply 3 years ago

how do i plug in my Linear Actuator in to my Vex Cortex Microcontroller? Answered

I know how to do servos and such, but the actuator has 5 wires, and i dont know where to put it.

Question by therobotman 6 years ago  |  last reply 6 years ago

linear regulator design, darlington, 5V dropout @ 2.5A !? Answered

The question says it all, really. I built up a linear power supply shown below. My unregulated 12V supply can fall as low as 14.7V @ ~ 2-3 A but if I end up being unable to go higher than 9.5V at 3A. Because I'm driving a motor as a load, the current drawn is very dirty. At 10V I see small dips that correlate to dips in the supply voltage when it goes just under 15V. So what can I do to help alleviate this, as I was under the impression that I would see a absolute maximum of 3V of dropout, not a whopping 5V. (p.s. the maximum gate current into the S8050 is 10mA, but currently set to 6.77mA w/ a 10 ohm resistor) p.p.s: MY design uses an LM324, which is really not the best, as it's slow and cannot sink much current. To alleviate the first issue I simply added current mirrors to aid the op amp in sinking current in a simalar fashion as a current source used for an open collector outputs. What op amp should I use instead for better performance? I suspect the LM324 due to it's low slew rate and low GBP may cause poor high frequency rejection (esp. if I choose to use a switching pre-reg) and poor high frequency load regulation (causes poor transient response on the output) Op amps I can choose from: LM324; // slow, from my testing, this one has inputs that work to ground :D LM224; // ditto, but in a weird package LM386; // slow, but from my testing, this one also has inputs that work to ground. LM741; // ancient relics of the past, not rail to rail by any means, sucks IMO. UA1458TC // ancient relics of the past, I don't have much knowledge of them. Inputs do not work to ground. LM318H; // its in a fancy metal case :D TL072CP; // JFET inputs, but I think the output current is limited and the output can't go below the noninverting input. TL2072AC; OP37; // These things can't even give a stable output by themselves! OP27; // ditto LT1007; // have not messed with it much LT1167;  LT1191; LT1363; CRAZY fast, 1000V/uS!!! Maybe too fast... LT1360; LT1112;

Question by -max- 2 years ago  |  last reply 2 years ago


Hey,    I have a robotic project that I have a deadline for. i have everything in place, but i cant think of how to connect the linear actuator up to my Vex Cortex Microcontroller. it has 5 wires, but I cant fit them in any of the outlets. Sincerely, I cant give my name out

Topic by therobotman 6 years ago  |  last reply 6 years ago

Linear actuator wiring question

I have a 73 Bronco, I am trying to install a set of step bars onto. I would like to have them mounted on a linear actuator. Is it possible to have them wired to a door jam switch, so they would lower when door is opened, and raise when closed? Every switch I have seen is a toggle, which won't work for my application. Any help would be greatly appreciated! Greg

Question by greg dill 6 years ago  |  last reply 6 years ago

linear strip photovoltaic panels

Hi, I was wondering if anyone knew where I could find strip PV (photo voltaic) panels. I have small pv panels 3in by 3in but i am looking for longer strip pv panels maybe an inch long by however thanks Jon

Topic by gwydionn 7 years ago

Linear magnetmotor - the basics for a beginner

Designing what is said to be impossible can be tricky, so I will try to give you some tips to reach your goal a bit quicker.A lot of people these days try to start with a wheel.Makes sense in one way as the final goal obviously is something that would rotate.However, considering angles in a rotating system is far easier with a usable baseline!We developed the liear motor well after any rotating electric motor.But only because someone already invented it for us.Making it flat was then more or less about finding a need for it first, like the modern highspeed trains on a maglev principle.If you want to make something move then it makes no big difference if you do it in flat or round.Flat however leaves you more options and much easier adjustments.And you will need a lot of the later...IMHO the best size and option for linear is the N0 model railway system.Tracks are only 3CM wide and second hand carriages to salvage the wheels is cheap.Either way, how would you start?We have multiple choices, like single row of magnets or double, maybe even tripple.Same for the actual magnet orientation.Flat, angled, attracting or repulsing...They all work if you understand how they actually work.Not the principle, the magnets ;)You see, a magnet always has two poles and without trickery both poles will be of even strenght, size, angle to each other and so on.Playing on a small and flat track with little resistance allows to use tiny magnets, like 5mm disc ones.If you follow the common concept of two magnet rows either side at a slight angle then you are half way there.People spent a lot of time trying not only to let the cart being attracted by the first magnets but also to let them pass out at the other end.In case you wonder why:Being able to be "sucked" in means you will have some force pulling on your cart from the next stage.Being able to fully pass through and preferably gain speed, means the cart would go from one set of magnets to the next - motion is accomplished.Let me give you my personal favourites for 5mm disc magnets:1. The rows are at an angle of 4-5° like a slim V-shape.2. Same as above by with the orientation changed by 90°The first basically means you have the magnets facing up while in the second you would have them mounted vertically.Both have good and bad sides and I think it is easiest to start with the first option.Here you would have a row of magnets at a slight angle either side of the track.Lets say it is all pointing away from you, then the north row would be left, south row on the right of the track.If you start narrow or wide depends if you want attraction or repulsion forces to work with.Again, it makes no big difference really, just a different way of operation, most seem to prefer repulsion though thinking the forces are greater - this is not true though ;)A very often copied way of mounting the working magnet (s) on the cart is by placing a magnet with south facing down on the left and one with north facing down on the right of the cart.Here you have the big problem of manipulating fields.The forces are quite strong and it seems the obvious choice but should be left for the advanced classes.Let me try to explain:No matter the site of your work magnet it has a very narrow acting field.Means you have a lot of attraction forces going only downwards and not providing any energy to move your system ;)If you orientate a magnet (stack) so north faces to the right and south to the left on either side of the cart you have more options.If the stack or single magnet has the correct length to match the angle of the magnet rows then a funny thing happens.Assume the outer most magnet is at about the same distance from center as the first magnet in the row.Means the inner most and opposing one is further away and the attraction forces gain the upper hand.While moving along though it moves away from the magnet row and whie still gaining force the last magnet in the row stops the cart dead center.This is the common scenario you see on the web when people try and fail.Now if you change the length of your working magnet and position in relation to the magnets in the row you can use the changes to your advantage.You can add slim disc magnets either side of your stack and observe the change in behaviour and where the cart starts to be repelled or gets stuck.In a bad case it starts fast but then stops with a big wobble back and forth.The perfect balance and size means the cart is attracted once it comes close to the magnet rows.There should only be a tiny sopt of very little repulsion right before the cart takes off.Like a hair trigger on a good gun if you know what I mean.It should then see some accelleration till about magnet 5-7 in a row of 14.From there it should level out and roll trough and keep rolling.I assume your first attempts now get you to the point where you cart start really nice, slows down a bit and seems just to miss a tiny extra push to make it out.It it shoots to the last magnet in the rows and then settles back to one or two before the end you are close!We have now two basic ways of manipulating the magnetic fields in our favour, or to "cheat" phsyics.Closing the gap.You will have realised by now that you need at least two stages for your system to be tested properly.Preferably 3 to get a 120° angle in a rotary conversion, but 5 would make sure there is hickups.This also means distance is now something to play with.Remember the pull before get at the same level with the first magnet in the rows?This is the first force we utilise by bringing the second stage at a distance CLOSE to take over the pull.Close because we don't want it to pull the cart out just like that.It would create a big "bump" and in a rotary system massive and unwanted vibrations.Instead we weaken the last magnet in either row.We still want to keep its pull but not so much the holding force that makes our cart go stuck here.Placing a magnet orientated in the same direction as your rows at the end of the row will change how and where the field of the last magnet in the row goes ;)Just to be precise: If the magnet in the row is north up and south down then the added magnet should have the poles 90° to that and in the same direction as the row.Depending how high, how close and with wich pole you place it the fields will change.You want to lower the locking force by at least 50% here - that will be suffient to overcome the holding force and gives the next stage a good chance to take over.It can also help to provide a sacrificial pole below the last magnet in the row.Again if north would be facing up then the lower magnet would also face north up but with a small distance to the upper manget.Ok, what happens here exactly?If I would want to be precise here you would need to read an awful lot, so make it simple...The lower magnet provides a way for the upper magnets south pole to get somewhere else instead of back to its original north pole.It also means there is another north pole "pushing" the north of the upper magnet more flat at the bottom half.This weakens the field strenght.Distance is key.The added magnet at the end does a similar thing.It provides attraction or repulsion forces that affect the field shape of the last magnet in the row.Imagine you have north facing towards the last magnet:You would push the last bit of the field up while also providing a very sharp end instead of a big round shape.The south pole of the last magnet also gets attracted by this added magnet, even more with one magnet below it.With those two added magnets you should be able to fully overcome the binding effect stopping your cart.It won't start and keep going when you let go of it half way down the track though, you need to start with the first magnet or give it a push to overcome the first binding effect.After that momentum takes over.If it really is that simple then where are all the successful videos about it?They are out there, you just need to look quite long for them.Most people still literally think only linear.A magnet has north and south and we can't change it - but we can...With field manipulations as above and shielding we get so much more than what physics currently dictates.Keep in mind that adding shielding under your rows of magnets will also affect how all works together ;)Some people forget this when using ferromagnetic things way too close to their testing area.Distance is also vital to keep in mind when experimenting.The closer two magnets are greater their forces to each other.You can utilise this for example by lowering magnets that seem to be far too strong in your configuration and cause a binding effect ;)And as said, shielding is nice thing for triack too - imagine what would happen with sielding on the sides of your magnet rows... ;)Make a negative into a positive!Extremly strong binding forces at a certain point in your track design can mean you might be able to utilise it instead of trying to waste it.Added magnets can divert the field to quite some extend.Shielding however can also direct them somewhere else - like in the core of a transformer where it all goes in a great circle.Even strips of shielding connecting magnets from one row to the one on the other side of the track can be utilised.Like that you turn two small magnets into one long one with twisted poles at the end.Provides more field strenght too and makes it good for areas with little to no attracting force to the cart.Then there is bigger design...Some people add a center magnet.With one on the cart and one in the center of the track you can create a cancellation field.The rows bind while the center magnet wants to push.If place where there is still enough forward momentum or even acceleration but close enough to the binding magnets it is possible to greatly lower the binding effect.But keep in mind you need to consider the added repulsion or compensated the field so it is most active towards the moving direction and less strong to where the cart is coming from.Advanced manipulations.You can machine magnets, sandpaper, file, grinder, CNC....Imagine you cut a square dice magnet from one corner to the other.Depending on how you have the field orientation you can end up several variations.But if north faced up in your dice then it will still face up in the cut pieces!Cut a pyramid and you end with a big flat south pole and a pointy north pole - and with extreme field strenth in this pointy bit.Similar story with half moon shapes.Imagine you machine a flat block magnet so you have a half moon with its pointy bits facing down and big round bit up.If north was up in the block and you shape the moon correctly then you end with two strong south pole points and a north pole that is strongest right between those points.Why is this so interesting you might wonder?Imagine you already know a magnets pole does not care if gos back to its own opposite or that of a different magnet.Then you also know you can machine and shape magnets to your will.Now imagine that for a change:Precisely machined pyramids that have the top chopped off.All tops in this example facing being the north poles and big bottom south.If you then machine a precise iron core block you make a nice cube.With magnets we need really good glue and a good press to make it happen.But if the center core is of proper size then we end with a block magnet that has a south pole on all sides.Of course to be 100% perfect we would need a zero tolerance gap but good glue and high forces can come quite close.Works as a sphere too but would even have clue where to start to machine the magnets LOL

Topic by Downunder35m 7 weeks ago

Questions about linear actuators?

Im looking for some info on how to make some small (10-20cm) linear actuators. or if anyone knows were they can be bought that would also be helpful.

Question by bamphy 9 years ago  |  last reply 7 years ago

Wanted: Controller for Linear Acuator

Basically, I need a dial that would command this linear actuator to advance in one inch increments on either a dial or a touchpad or a slider. or 917 414 5472 Thanks! Evan

Topic by EvanB65 1 year ago  |  last reply 1 year ago

Seeking someone to hire for a project

Hi, I'm not sure if it's appropriate to post this inquiry on instructables but I thought I'd give it a try. Basically, I need a dial that would command this linear actuator to advance in one inch increments on either a dial or a touchpad or a slider. I'm not an engineer and I don't really have time to build this myself - would anyone be interested in doing this for a fee? If it would help in assessing the project, I now this controller would work However, I need the dial or touch pad to allow for discrete steps and not be sort of vague. Any help would be much appreciated. I'm just not sure where else to turn. Thanks, Evan

Topic by EvanB65 1 year ago

Linear electric water pump?

I need to figure a way of moving fluid along a pipe without anything in the water (i.e no mechanical bits) would a coil around the pipe produce any movement?

Question by tommo1000 7 years ago  |  last reply 7 years ago

wiring a linear actuator with relays

  Hello everyone. I'm trying to run a linear actuator with built in limit switches by remote control. I bought the remote from a parts store. The remote was supposed to be used for windows up and down, door locks and other stuff. I would like to be able to use the relays that I already have on hand. I want to be able to push a button on the remote and the actuator go all the way out or in without holding the button down the whole time. Thank for your help.

Topic by papermaker007 7 years ago  |  last reply 7 years ago

Simple linear motor design ? Answered

I need a simple, not powerfull, linear engine. It has to move just like an inch back and forth, chaning directions on its own when it reached the end of his stroke. Even 5mm would be enough movement. I think about of something based on a neodymium magnet in cylinder shape. It has to be as simple as possible, i don't need any control for frequenzi, because if it works.. i can work out more from there on my own. Only thing important, it has to be small, like the lenght of a half pencil and 2cm in diameter would be ok (for the moving part, electronics placed elsewhere don't matter). A normal rotating engine with a shaft doesn't work for the design i have in mind :(

Question by wupme 10 years ago  |  last reply 10 years ago

forked threads and linear threads

Hi. It's about how are organized threads into forums. Currently forum threads are forked : you can reply to a comment separately, and each of your reply will make a new fork if somebody reply to your new comment ... this makes threads like trees ... Personally, I don't find this system very handy, more particularly when the same thing is being actively discussed in several forks. This system is good for short chats and when commenting instructables, but when it's about debating, it quickly becomes confusing ... For the forums, I'd prefer a system with a linear thread where messages are ordered according to time, and where we have to quote the persons we want to reply to. Several discussion could get "multiplexed" on the same thread, but personally, I find that less confusing as long as there are quotes. What's your preference ?

Topic by chooseausername 11 years ago  |  last reply 7 months ago

Linear LED ammo Counter? Answered

So, my friend and I are building a Coil Gun!  Nothing super powerful, but it will punch a nice hole in a cardboard box.  Here's the problem; we want to add an ammo counter to it.  We were thinking of using an IR LED, a Photo-transistor, and a voltage comparator circuit, kind of like the one here ( , first photo, right circuit)) .  The circuit would send a pulse when the projectile interrupted the IR beam. Now what?  The magazine holds 6 rounds, so maybe 3 green LEDs, 2 yellows and 1 red to count the ammo.  We were thinking of maybe using a 4017 counter IC to advance down an LED after each pulse, but doing it this way means only one LED is lit at a time.  We would really like it if somehow we could have all the LEDs lit, and after each pulse one would turn off, but I'm unaware of how to do this.  Oh yea, we don't have access to a micro-controller, which is why we have this problem.  So to recap, we need a circuit that will light 6 LEDs when powered on, then shut off one LED for each pulse received.  Is there any way to make a circuit that does this?

Question by aeronut01 6 years ago  |  last reply 6 years ago

LIM Question

I have a question about linear induction motors. I can't seem to actually find the answer anywhere. Is one rail a permanent magnet and the other an electromagnet, or are both of them electromagnets?

Topic by puffyfluff 10 years ago  |  last reply 10 years ago

*linear* PWM LED fade with arduino

Arduino comes with a simple program to make an LED fade on  or off, however, as far as I can tell, the apparent brightness of the LED does not change linearly with the wpm duty cycle. After some research I found that this is because humans percieve brightness logarithmicly, not linearly. (Also, LEDs don't change brightness linearly with current, but sisnce I'm using PWM, i don't think that comes in to effect.) I found a simple look-up table to correct for this on this page. 255, 180, 128, 90, 64, 45, 32, 23, 16, 12, 8, 6, 4, 3, 2, 1,0 This seems to work very well, but I don't know where this comes from. Does anyong know the ectual equation to get the % duty cycle from the %brightness? I like to abstractise things.

Topic by Vick Jr 8 years ago  |  last reply 7 years ago

Clarifications about a linear induction motor.

Several questions: -Calculate the force of a linear induction motor from the magnetic field/current (aluminum induced surface)? -How does one determine the direction in which is moves considering the magnetic fields are not static and there isn't a second magnet since it is just an aluminum induction surface? -Is there an optimal current frequency for a linear induction motor? -Is there any way to make a single phase Linear induction motor, and avoid using 3 phase current?

Question by amelius 6 years ago  |  last reply 6 years ago

how to prevent voltage change using zener diode?

Zener diodes only regulate voltage when it is within its regulation range. in a simple zener regulator, voltage in the resistive load changes as the resistance of the load changes, but this is usually a small change. now, my question is, is it possible to prevent this small change? how?

Question by codestroy7 7 years ago  |  last reply 7 years ago

lift table from old adjustable bed

Have two old electric linear screw actuators that work great. I Need a lift table but can't figure out how to put it all together. I don't know what width or type of metal use for the lift or the bolt hinges???.  Does it have to be a scissor lift or can I keep the actuators where they are at each end of the bed, wire them to work together and make a lift that way?  I need an affordable way of doing this and it only needs to lift to about 500 lbs. from 17 inches off floor to 30 inches off floor.  All framing is angle iron but seems heavy duty. Anyone's help if greatly appreciated as I just cannot afford to spend $ 1000. + on an electric massage lift table. The pic is after everything but the motor/actuators were removed. Thanks Deb

Topic by DebMaudie 3 years ago  |  last reply 3 years ago

How to tilt a bed / linear actuators?

I'm thinking about making an alarm clock that literally gets me out of bed! The alarm clock would start tilting the bed to one side, untill i either get out of bed, or fall out of bed :) I was thinking of using linear actuators on one side of the bed to do the tilting. Does anyone here have any experience with linear actuators? How strong are they, and where can I buy them cheaply? Any other ideas on how to tilt a bed? Cheers - Chr

Topic by chr 11 years ago  |  last reply 11 years ago



Topic by maeku 7 years ago

wiring limit switches on a linear actuator

I am trying to wiring two limit switches onto a linear actuator. One to stop the extend stroke but will allow you to retract the actuator. The other limit switch will stop the retract stroke but allow you to extend the actuator. The actuator is installed on a door I need it to stop on the extend stroke and the retract stroke so it doesn't damage anything. I have an LACT8-500A actuator and the company doesn't make a limit kit for the adctuator.

Topic by youaintwrong 8 years ago  |  last reply 8 years ago

linear input to control a rotating servo? Answered

Im trying to build a circuit in which an input uses linear motion to control a rotating servo. the servo rotates clockwise/counterclockwise, and the input should have 3 inputs. turning the servo clockwise, turning the servo counterclockwise, and a neutral option so the servo doesn't have to always move; the neutral would be between the to rotation inputs. The closest form of an input I've found so far is a sliding potentiometer since it is controlled by linear motion. If there's a better input that can have those 3 inputs i'd love to know.

Question by explosive_bagels 7 years ago  |  last reply 7 years ago

help with a coil gun (or linear accelerator)?

hello, i want to make a coil gun (or something) where is a good place to get capacitors (short of buying them of coarse)? any help (nomatter how off topic would be lotsa help) thanx!

Question by cheesewzrd 8 years ago  |  last reply 8 years ago

Linkage for Linear Motion from Servo. Answered

  This was originally going to be a question on mechanical advantage and tinsnips but I've realised the answer during typing the question. So, my follow-up question is . . . I'm looking to extend the throw of a servo and convert this to a roughly linear motion but still keep the whole mechanism compact.  I'd like around a 4 to1 gearing (with corresponding loss of force, of course).  Is there a simple linkage I should be looking at to get this?

Question by AndyGadget 7 years ago  |  last reply 7 years ago

Turning horizontal linear motion into vertical

Hi guys, I have a dmx controller which is connected to two sunstrip lights which I control with my foot during gigs. It means I have to balance on one foot and slide the fader up and down with the other in order to get a swell/strobe effect. Have you any idea how I could hack it to turn the horizontal linear motion of the fader into a vertical motion (basically a pedal I can stamp on it swell like a wah) Any suggestions helpful. Cheers!

Question by DaveP177 3 months ago  |  last reply 2 months ago

Hack your Servo V1.00: Make a powerful linear actuator using a standard hobby Servo

Hack your Servo V1.00: Make a powerful linear actuator using a standard hobby Servo   Provided you have the tools and the servo you can built this for under a couple of bucks. The actuator extends with a rate of about 50mm/min. It is rather slow but very powerful. Watch my video at the end of the post where the small actuator lifts 10kg vertically.   Materials List Tools list   - hobby servo - standard hobby brass tubing             -OD: 4.0mm, ID: 3.4mm             -OD: 5.8mm, ID: 4.5mm - standard hobby styrene tubing                                                 -OD: 4.8mm, ID: 3.5mm - M4 studding - 2 x M5 washers - 2 x M4 nuts - 5 minute epoxy - cyanoacrylate - grease - multi-strand cables - heat-shrink tubing   - standard tools – screwdrivers, scalpel, files etc. - dremmel multi-tool with ceramic abrasive disk, or similar - hand-drill + 4.9mm + 2.5mm drill-bits - M3 tap - M4 tap - soldering iron - glue gun - small vice - small saw - sanding paper (relatively fine) - small flame torch Procedure - I will be giving instructions based on the dimensional parameters of the Hitec HS-300. The procedure remains the same for any type servo. I strongly recommend you read the whole post before you start. So lets make a start, shall we?   - Open your hobby servo, remove control electronics, feedback potentiometer and mechanical stop on the servo’s output gear.   - Solder new cables on the servo motor’s leads.   - Drill two 4.9mm holes on the servo case bottom cover. These should be located longitudinally along the centre line and 9.5 mm from each end (this applies on the Hitec HS-300 and is also true for many standard servos but depending on your servo type there might be differences). The M4 thread will come out from the servo body using one of these two so this hole must be located directly below the centre of rotation of the servo’s output gear. Be very careful since this alignment is very important! If you don’t get it right you might have to use a new servo! The more accurate you are, the longer your servo will endure. -  Measure the dimensions of the rotating shaft of the potentiometer on the servo’s original electronics – note the geometry in general. The shaft should be flattened right at the tip in order to prevent it from freely-rotating once inserted into the servo’s output gear.   - Take the M4 studding (M4 thread) pick one end and by using the dremmel and the abrasive wheel tool, replicate the tip of the servo’s potentiometer on that end. Start by decreasing the diameter of the thread, rotating it steadily by hand against the abrasive disk (normally to 3.5mm in diameter and at least 6mm in length). Try to think of your fingers as the chuck of a slow-turning lathe. Once the diameter of the thread is down to the pot’s shaft diameter, flatten the tip according to the potentiometer’s tip. The idea is that the thread must be inserted in the servo’s output gear in the same way the potentiometer did before. The better the fit the longer your servo will endure. - On the flat tip of the M4 thread, screw the two M4 nuts approximately 20mm down its length. Following that, insert the two M5 washers. - Insert the thread inside the servo and adjust the distance of the nuts and washers down the thread such that the servo case bottom cover closes properly and the motor rotates efficiently. Basically, you have to make sure that once the thread and the servo are assembled there is no pressure between the servo case bottom cover and the nut-washer assembly. Similarly, you have to make sure that once the thread and the servo are assembled there is no gap between the servo case bottom cover and the nut-washer assembly. Once again, the better the fit the more your linear actuator will endure.   - Once you find the optimum position carefully disassemble the servo, remove the washers from the thread and use a drop of cyanoacrylate on the side of the nut that was in contact with the washers in the assembly. Let the glue to settle for 5 minutes. Unscrew the second nut by 10mm towards the flat end of the thread, and prepare a small epoxy mix.   - Put the mix between the two nuts and screw the second nut back in place. Once in place also use some epoxy on the back of the second nut as well. Ideally you should sand all contacting areas before you apply the epoxy glue. Leave to settle for at least 6 hours (even if you use a 5 min epoxy). - Secure tightly the 4mm diameter brass tube onto a vice by flattening the mounting end and use the M4 tap VERY carefully tapping as deep as possible (at least 15mm). Using the dremmel cut 10mm out of the threaded part of the tube and then verify that the created thread runs along the whole length of the small threaded tube by screwing it onto an M4 screw. Keep the 4mm threaded tube on the screw for handling purposes. Apply a layer of solder on the outside surface. - Take the 5.8mm diameter brass tube pick one end and try to sand at least 5mm into the tube (on the inside). Mount the brass tubing on the vice without squishing it and apply a thin layer of solder on the inside.   - Ignite the flame torch, take the 4mm threaded tube (holding it by the screw) and move it on the soldered end of the 5.8mm diameter brass tube which should still be mounted on the vice. Using the flame torch heat-up both tubes and carefully insert the 4mm threaded tubing inside the 5.8mm tubing until is fully inside. Use a pair of pliers and insert the brass tube by holding the end of the screw that sticks out. Hold the threaded tube levelled inside the 5.8mm tube until the solder settles. If you do not have a flame torch use a candle, your soldering iron and your patience :). Remove the screw. The end result will be the cylinder of your linear actuator. - The cylinder length should be equal to: the actuator’s desired working length (stroke) + length of the 4mm threaded tube which is inside the 5.8mm tube + 10mm for the mounting hinge at the cylinder end.   - The thread length should be: the actuator’s desired working length (stroke) + length of threaded tube which is inside the 5.8mm tube + length of the thread which resides inside the servo casing, which is model-dependant.   - Take the non-threaded/non-soldered side of the cylinder and drill a 2.5mm hole through, 5mm from the tip. - Cover the entire length of the cylinder with heat-shrinking tube and cut-off any excess bits. The 2.5mm through holes made earlier on the non-threaded side of the cylinder are now covered. Use the drill again to expose them and tap them through, using the M3 tap. Screw a 20mm long M3 studding or simply cut-off the head of a 20mm long M3 screw. This will act as your cylinder mounting hinge.   - Take the 4.8mm styrene tubing and M4 tap it 10mm deep. Cut a small ring 5mm in length and screw it in the M4 thread fully, from the side of the nut that was in contact with the washers (long side of the M4 thread). This will act as bushing between the thread and the servo’s case bottom cover. Ideally you should use nylon, copper or metal bushing. - Secure the motor cables inside the servo casing using a glue-gun and use heat-shrinking tube to cover them. Assemble the servo including the thread, the styrene bushing and the washers.   - Screw-on the cylinder and you are good to go! Here is a video of the small actuator lifting 10kg For those of you that have watched my video on the MTR Rover     will understand where the idea of hacking the servo came from ;))   Soon we will be posting assembly instructions, code and schematics on how to modify a standard servo to get full PID speed and position control with 10-bit resolution over 360 degrees – continuous ;)     I look forward for your comments!    

Topic by Antonb 9 years ago  |  last reply 9 years ago

X-Y stage for film scanner

I'm building a film scanner using a dlsr. Here's a picture of the rig so far: Basically there's a light source, negative stage, negative holder, camera support stage, camera and lens.  I put a negative in the negative holder and slide it using a guide such that I can take a bunch of pictures of the negative at 1:1.  For example, it takes 25 pictures to cover a 6x7cm negative.  The individual files are then combined into one file using stitching software.  The system works very well, but it's a bit tedious.  I'd like to automate the negative movement using a diy motorized xy stage.  Many of the designs I've seen are for much bigger units, such as for a cnc machine, or units that require speedy movement.  That's not the case here.  Each movement would be only 10-20mm. I'm fairly handy, and I can follow directions/recipes well, but I haven't worked with arduinos or stepper motors before.  Any advice or suggestions on a good way to accomplish my goal would be very welcome!

Topic by pdesmidt 7 years ago  |  last reply 6 years ago

Power Supply Question? Answered

I want to build a switching Power Supply, without the use of IC's with everything already inside. I only want to use op amps and passive components. Below are my goals on what to achieve. I would like to make this PSU current limited, or at least shut off when the current goes too high. I basically took the concept of the linear voltage regulator and expanded on it, turning it into a 'proof of concept' switchmode supply. Input Voltage range: . . . .7-24 Volts Voltage: . . . . . . . . . . . . . . 5-24 Volts Max Current: . . . . . . . . . .10 Amps Price: . . . . . . . . . . . . . . . . $5 -- $10         Instead of feeding a voltage reference into an op amp, I modulated it with a few components. (A triangle wave generator, and a array of resistors to lower the amplitude and introduce a DC bias.) The DC bias is controlled by the current protection module, which is simply an op-amp that reads the voltage on a small resistor and multiplies it by 5. This finalized current controlled, DC reference biased triangle wave is fed into a comparator, which will then switch a rather large MOSFET on and off at about 200 Hz, with varying PWM, depending on how much 'droop' there is on the output. Here is a rundown of what the components will do: OK, I refined my plan to this general specs: Input Voltage range: . . . .7-24 Volts Voltage: . . . . . . . . . . . . . . 5-12 Volts Max Current: . . . . . . . . . .10 Amps Price: . . . . . . . . . . . . . . . . $5 -- $10        I basically took the concept of the linear voltage regulator and expanded on it, turning it into a 'proof of concept' switchmode supply. I don't want to use any prebuilt chips where you have a magic black box with inductors, capacitors and resistors connected to it. I want this to be entirely raw, basic, cheap parts. Maybe later, I will replace many of the op amps with a single programmable chip (like an Atmega328P)         Instead of feeding a voltage reference into an op amp, I modulated it with a few components. (A triangle wave generator, and a array of resistors to lower the amplitude and introduce a DC bias.) The DC bias is controlled by the current protection module, which is simply an op-amp that reads the voltage on a small resistor and multiplies it by 5. This finalized current controlled, DC reference biased triangle wave is fed into a comparator, which will then switch a rather large MOSFET on and off at about 200 Hz, with varying PWM, depending on how much 'droop' there is on the output. Here is a rundown of what the components will do: Green field: This contains a voltage regulator which acts as both a 5V power source and a voltage reference. Not only will this module produce a 5V output, but also produce a triangle wave. Blue field: This module will be fed the triangle wave, decrease it's amplitude, and inject it with a bias voltage, controled by the current limiter (red field). Red field: This basic module simply measures current flowing through a 0.1 Ω resistor, and multiply that reading by a factor of 10, and inert it (the circuitry is probably wrong, and I am not sure how this will work, if it even will do what I want it to Will this work?) Yellow field: The final modulated triangle wave is then fed into the last comparator, which will switch a MOSFET on and off at a fixed frequency of 200Hz. The output of this last comparator is now PWM. As the output voltage sags, the pulse width will increase, and cause the final voltage to stabilize at either the peak value of the triangle wave (with little to no load), or near the bottom end of the wave (with a heavy load) ------------------------------------------------------------------------------------------------------------------------------------ My questions:  I try to run this in LTspice simulator but some reason the output of the last comparator is a distorted triangle wave. I think this has to do with my filtering capacitor and MOSFET gate capacitance. Can anyone give suggestions about this design?  I'm sure the current limiting function is not going to work as intended until I finalize it's design (I hope I don't need more than 4 op amps altogether, It would be nice to use a single chip I already have) Any suggestions? I might just omit this part entirely, as it is not necessary.

Question by -max- 5 years ago  |  last reply 5 years ago

How to concatenate two or more linear interpolants? Answered

I have a graph, it is not a straight line but a random curve, I want to do linear interpolation of different data set points. I read it here: And it says that: "Linear interpolation on a set of data points (x0, y0), (x1, y1), ..., (xn, yn) is defined as the concatenation of linear interpolants between each pair of data points." So. how can I concatenate two or more linear interpolants? And can you please also give an example of it?

Question by Wisaam 5 years ago  |  last reply 5 years ago

the use of threaded rods for cnc miller and cnc 3d printers

I got some threaded rods today. They look straight. 16 threads per inch.  The tag on one of the shorter ones says 3/8" - 16x36", course threads, zinc plated 1700lb. I was planning to use these for the x,y,z control for a 3d miller/printer. I realize it may be slow. Someone mentioned that the McWire repstrap uses a 4 1/20 (the only part I understand is 20 threads per inch) was really slow, but someone made it work with 2 1/16. I did not really have plans to attempt position verification because I think the resistance vs torque should be minimal for a threaded rod setup. I figure I could get away with just sending it specific pulses for a specific amount of time. Could I have some feedback on this?

Topic by nstenzel 6 years ago  |  last reply 6 years ago

Antique Bicycle, Human Sonar, The Linear Clock

Antique Bicycle Human Sonar The Linear Clock Learn Business Card Throwing DIY Gorilla Pod Make Whimsical Furniture Kids Riding Crane Gourmet Chocolate Truffles Kill Bedbugs With Christmas Lights Instant Limoncello Cardboard Cryptex Vault $3 Xbox Kinect TV Mount Remove Vinyl Tiles With Dry Ice Challenging Bolt Puzzle Build a Printing Press

Topic by randofo 8 years ago

Torque to linear thrust through lead screw

Hi,I am trying to figure out maximum linear force I can produce with an electric motor through use of lead screw and nut. I have come up with an equation which seems correct but resulting forces are way higher than my intuition believes is correct.I tackled the problem from the perspective of energies:F' * p = M/r * 2*π*rlinear force * thread pitch = torque / radius [M/r = force at radius] * circumference of lead screwF = 2*π*M/p * (1-k) //k stands for coefficient of friction between lead screw and nut)Radius falls out of equation, which seems fine as force is provided by torque, which is radius agnostic. I used a 7€ stepper for source of torque which can provide 0.42 Nm of torque and a lead screw with 8 mm pitch and 4 mm radius, I assumed 15% losses. My equation tells me that such system can provide 280 N of force, which seems wayyy too much for a cheap motor.I have attached a python code that calculates linear force in case it helpsCan someone tell me if my equation is either correct or flawed?

Topic by ptkrf 7 months ago  |  last reply 7 months ago

How does the num. of turns & voltage on the primary translate to an ideal voltage on the secondary?

In electronics, one of the things that has been the most confusing to me is the physics behind transformers. I have learned of that stupid formula a while back, where the ratio of turns is proportional to the voltage ratio and inversely proportional to the current, however, I know from reality that it is no where near that straight forward. As far as I can tell, it is a bunch of BS. Anyway, I want to know what the REAL story is, how the AC current going through the transformer is related to the magnetic flux through the core, and how that relates to the output of the secondary. What seems counterintuitive to me is that more windings on the primary should yield to a stronger magnetic field in the core for a given current, which means for magnetic flux (???) which seems like it should yield to more induced current in the secondary. Is the answer related to inductive reactance (more turns = more inductance = more inductive reactance = higher impedance at a given sinusoidal freq. = less current per unit of voltage?) Note: If you have a good physics and calc background and understand it to heart, pls do explain. However, I am currently only nearing the end of calc 2 w/ absolutely no formal education in physics, so I may have some difficulty with wank terms and vocab. (a.k.a. do not try to show off how many terms you know attempting to explain things in the most complicated and technical way possible.) Also, any good tutorials online that go into depth into the topic? ----------------------------------- The reason I want to know these things is that I wasn't to build a good 6A 0-+/-15V dual isolated channel linear power supply with many transformer tabs so I can keep the voltage drop on the pass elements as low as possible at variable output's so huge $$$ heatsinks are not necessary due to lower low power dissipation. (I have mostly figured out the LPS circuitry, but have not found a suitable Xformer online.) I can get the laminated magnetic cores needed relatively cheaply, however if I have to do some custom windings, I want to make sure I do not choose the wrong number of windings for the core. (obviously one turn on the secondary and 5 turns on the primary will pop a breaker @ 60Hz... )

Question by -max- 4 years ago  |  last reply 4 years ago

Need a cheap dual-output, center tapped, 180VA 18V 5A transformer?

I am trying to design a nice dual-rail lab power supply and need a cheap dual-output, center tapped, 180VA 18V 5A transformer. The outputs are as follows: Primary: 120V Secondary 1:  9V-0-9V, @ 5A max. Secondary 2:  9V-0-9V, @ 5A max. ======================OR==================== Primary 120V Secondary 1:  9V, @ 5A max. Secondary 2:  9V, @ 5A max. Secondary 3:  9V, @ 5A max. Secondary 4:  9V, @ 5A max. I prefer a transformer for the linear regulator over a switching preregulator, because a switching preregulator sort of defeats the whole purpose of making a nice, high precision, low-noise lab instrument. However, I also prefer to have more than just 2 separate 18V outputs, since that means when the output is shorted and constant current mode kicks in for either the positive or negative rail, I will have a voltage drop of 18V, at a maximum current of 5A, and thats over 90W of power dissipation!!! I think that I can deal with that if thats the only solution, since I am planning on using a large CPU active heatsink for cooling, but I prefer if I was not pushing a TO-247 device to it's thermal limits. I have found this: It is affordable, but it seems strangely cheaper than a lot of other toroidal Xformers on the market. Also, the 2 primaries are not center tapped. It is 200VA though! I have never heard of that company, and it seems like the description of it is written in chinglish. They act like the fact that they over-engineered and under-specced it is a feature (to me, thats how all ratings should be, that should be normal and standard, not a feature.). I have also found this: It would be perfect, but it is $80!!! Very expensive, Also, I do not think it is a nice toroidal transformer, not that that matters much to be, I just like the professional look of a beefy toroidal transformer inside a power supply. Lastly, I have found this: It seems to be very similar to the first find, and it is from a reputable distributor. At $70 it is still expensive, and I do not want to spend over $100 for a homemade power supply. I would just get a off-the-shelf solution for that! What about the possibility of modifying a MOT transformer? How many VA or watts can I expect from the output without active cooling? I know they are rated from upwards to 1000W, but I also know they cannot sustain that power output for a long time without overheating and requiring lots of active cooling, and from what I remember, I believe the core is really being pushed into saturation during normal operation, leading to LOTS of power loss in the transformer core, but can they output 180VA continuously and effectively? Approximately how many turns of wire would I need to achieve my requirements, and what gauge wire should I use? I am thinking 20AWG but someone who has done that before would know better than me.

Question by -max- 4 years ago  |  last reply 4 years ago

I need a circuit that 'buffers' voltage applied to an electric motor to slow down its movements. For a record player.

I'm looking to build a circuit that slows the voltage spike sent to an electric motor. Something that would progressively apply power and progressively power down.It's for a linear turntable. The tone-arm is belt-driven by an electric motor. The issue is, the motor moves so suddenly that it creates an audible 'thump' in the speakers from the quick movement. Would a capacitor in parallel do this?

Question by CST10 7 years ago  |  last reply 7 years ago

would like to know where to wire the 10k linear potentiometer to the Lm317

I'm trying to build a Led Constant Current driver for my led grow plants but I'm stuck on where i would solder the 10k linear potentiomter on the LM317 By the way this is what I'm using 10k linear pot 1kohms fix resister 2.2ohms resister LM317 can someone please draw in color code where i would solder the 10k Pot wires to the LM317  please really appreciate it thank you

Question by lex76 3 years ago  |  last reply 3 years ago

Reduce steel tube diameter by 0.3mm Answered

I am trying to make a DIY CNC machine, using linear rails and the expert advice in the many awesome instructables out there on this topic.  I hit my first roadblock, and I need some help/advice please... The 16mm steel tubes I ordered for the sliding rails wouldn't fit in the 16mm linear slide bearings SCS16LUU that I ordered, they are ever so slightly too big. With a lot of force I could get the rail in the bearing, but it wouldn't slide without extreme force - certainly not the smooth sliding motion it's supposed to be! I've probably ruined the bearings by forcing it in, but I'm not worried about that so much right now (I have spare bearings). I broke out the digital callipers, and the rail diameter measured 16.3mm - that's .3mm more than expected, and more than can fit in the 16.0mm bearings. So now I need to reduce the steel rails by 0.3mm. I have only hand tools at my disposal, and no experience accurately reducing steel rod diameter. I guess another alternative is increasing the slide bearing diameter, but these are sealed bearing units and difficult to get at. Does anyone have any ideas ?  Would it be easier to order new steel? Please let me know any thoughts on this, I'm desperate here.  Thanks in advance,

Question by srah1 4 years ago  |  last reply 4 years ago

Looking for someone to help buld an Arduino linear measurement project.

I'm looking for someone to help me build an Arduino linear measurement project. I need to measure less than 6" stroke with some accurate repeatability. I'm willing to pay for the programming and any parts I might need. Email me if you are interested in working on this with any questions you have... Thanks, 

Topic by rpmlou 1 year ago

i want to drive 1960 N weight with linear speed 5km/h which motor is suitab for this? Answered

I want same speed with load and without load? plz ans this question. 

Question by AbdulH63 3 years ago  |  last reply 3 years ago

PSU design (major revisions): Transformer calculations help?

Recently I have attempting to design a proper dual-rail power supply that will allow me to set a voltage as low as +-1V up to +-30V in 0.1V increments at (hopefully) 3 significant digits (at least for the lower voltage settings). Anyway, this supply is also going to be current limited to up to 5A,again, it can be set to just about anything. I plan on using an Arduino micro-controller to set the output. In order to do this, I plan on using the analogWrite functions, or better yet, a legit DAC. There will be 4 outputs from the Arduino that will set the power supply output by applying a 0-5V voltage on the input of the 2 current limits and 2 voltage sets. (one for the negative rail, one for the positive). However, I have kept running into the same problem: how do I plan on driving this linear power supply with up to 200W*? My first idea was to use a a MOT, due to their high-power capabilities, and re wind the secondary with the right number of turns to achieve this output. However, I have heard that these transformers are not optimal for continuous running due to their poor and cheap design. (losses are very high). My second idea was to search around for a 250VA transformer. However, even until now, the VA rating confuses me. How does VA compare to W? I know this has something to due with reactive power, real power, and apparent power. However, I have no intuition of any of these 'powers.' How would I go about calculating the correct size transformer for the job, also, I am going to assume this linear power supply has the properties of a resistive load, since it is rectified and smoothed with a filter capacitor, so practically nothing should react with the AC power. (unless there is something more to the full-bridge rectifier setup I am considering.) This is when I came across unwound toroidal cores found on eBay for $25, the perfect price range! However, this has raised more questions! to start off, beyond turns ratio, I do not know now many turns I need for the AC side of things. I know intuitively and from experience, mains-frequency transformers do not work with only one (or even few) winding(s). I think this has to do with saturation, but I'm no expert by any means. and the inductive reactance of the transformer's primary. How do I calculate losses, inductance, and other important parameters of a homemade transformer like this? Things get very nasty when I look back at rewinding an old transformer. Now I have all these questions about inductive reactance, power, currents, magnetic flux and saturation, but also, about determining the original power rating of something like a very old small welding transformer or one from a large 10A car-battery charger. Is it possible to approximate the power by measuring the dimensions of the core? How close will this approximation be?  After getting frustrated with this, I considered alternative approaches. What if I purchased 2 ~20V ~6A SMPS (switch mode power supplies) connected them in series, and connect the center tap of my linear supply to the joining point between the 2 SWPS's? Would this be unstable and be bad for the SMPS if a load was connected between the 'outputs' of this new center tapped supply? Would any sort of balancing be required? Also, a bigger problem includes how this will be connected to my linear PSU design. With a low voltage @ high currents, I would be wasting a LOT of power, power that has to be dissipated away from the transistors. This heat can approach 200W, which is company unreasonable! Anyway, I would them have to either a switching preregulator, or modify the SMPS's so the voltage can be controlled easily and varied between, say, 3V to 20V. absolute accuracy is not required, close enough, and rest of my PSU should handle it. This becomes seemingly impractical too, and many other considerations need to be made. What should I do? what are the calculations and factors I need to know? i do not have an LCR meter to measure inductance, so trial and error is out. Does anyone here have experience at this? Help would be greatly appreciated! *The 200W figure was calculated by taking 40V, (What I believe would be a safe to allow some slack for +-5V voltage drop across my 2 shunts and transistors) and multiplying it to 5A of current for the maximum power output. ------------------------------------------------------------------------------------------------------------------- I have added an image of my current design, and I have modularized it the best I could. The YELLOW is all my current power-management circuitry. Currently just a transformer with many taps, going to a currently-undesigned switch box that will change the voltage on the output, which is then rectified and enters a filtering capacitor, finally entering the circuit.  The GREEN field is the voltage set. It is the most major part of the PID feedback loop, along with the ORANGE field. It works simply by feeding a voltage to the positive of a op amp configured as a comparator, and with negative feedback from the output. It then outputs a signal to the transistor, turning it either more ON, or more OFF depending on how the output voltage compares to the +Vset. The negative portion is largely the same, but the input voltage needs to be inverted so the output voltage is set negative properly. I was not able to use less than 2 op amps for this portion, unfortunately. The ORANGE field is current set. It works by measuring the voltage drop across the shunt resistor, and outputting a unity voltage that is referenced to ground, instead of to the positive rail. (It took me forever to finalize and perfect that!!!) Anyway, this voltage is then fed into a op-amp configured as a comparator to drive the transistor. The BLUE field is my switching regulation topology, which is controlled by both the ORANGE and GREEN fields. Do you like my use of diodes as a super-simple voltage or current selection switch? the op amp that outputs a lower voltage is the one that gets 'listened to' by the transistors. This way, current and voltage mode enable properly. This does add a small problem when it comes to powering the op amps, all of them have to be powered off of slightly higher voltages to swing the full range due to the voltage drops of those diodes. In the PINK field is simply a single-transistor solution to a constant current load. This allows the regulator to be regulated even at very low voltage set levels. This is why I am able to achieve a +-0.5V on the output (at least within LTspice) Finally, and most unimportantly, the light PURPLE fields have a simple ultra high-gain difference amplifiers that will detect if the output current and current set are the same, and turn On or OFF the respective LEDs. The green LEDs are voltage-mode indicators, and the red LEDs are to show when current-limiting mode comes on.

Question by -max- 5 years ago  |  last reply 5 years ago

Tesla coil output? Answered

Ok I'm experimenting with tops and linear transformers for therapeutic effect these seem to be the best combo so far could some aproximate what kind of signal is being out put with a step up linear transformer 4:1 and does it just feel good to me and disruptive to telecommunication it doesn't interfere with wifi

Question by wiccakingkamui 5 years ago  |  last reply 5 years ago

If I wanted to build a small linear accelerator what how would I make the electrostatic generator? Answered

I am going to build a small linear accelerator like the one rutherford used to bounce alpha particles off of a sheet of gold foil. Actually that is exactly what I am going to make. The only thing is that I am not sure how I would generate the electrostatic field. Would a van de graaff generator work, or would I need something different? if I do need something different how would I make it?

Question by Higgs Boson 7 years ago  |  last reply 6 years ago

PDF's are 0 (zero) bytes

I am a 'new' Pro Subscriber. I tried downloading .PDF from this posting using Firefox (and Chrome); files are zero bytes. What's up with that. What's the solution?

Question by squattingdog 4 days ago