Search for counterweight in Topics

Can anyone reverse engineer and make one of those elevator beds that are made with counter weights? They are becoming popular in Europe.  Ana White made one using garage door but it uses four corners.  The ones in Europe use only one wall or also add the ceiling across for the other end.  I like the one that spaceurc_com has which uses counter weights. BedUp_fr & espace-loggia_com seem a bit more difficult.  I can build a murphy bed, but these are a challenge and I like a challenge but it is too technical for me. Thanks for your help.

Hi everybody.  I am going to make a loft bed that will raise automatically when my kid gets out of it.  What I'd like to do (please see attached files) is suspend the bed via pulleys and cables attached to one weight.  The weight would be just a pound or two (trimmable, of course) more than the frame, mattress, bedding, etc. so it will raise itself until the weight hits a stop leaving the bed a few inches from the ceiling.  If necessary some friction could be used to keep the speed reasonable.  At night it should pull down quite easily, and I believe that with this layout, it should come down evenly regardless of where it is being pulled.   I had wanted this to "float", but since it is going to be in a corner anyways, I may run a couple tracks down the wall with hardware to guide the bed and keep it from swinging. The big question I have is how to fasten this to the ceiling.  It is drywall with joists above.  Offhand I'm guessing the bed will be say 110 pounds, so about 225 pounds hanging from the ceiling with the bed empty.  I'd like to have an extra, what, 500 pounds wiggle room?  Worst case scenario, two 150 pound people sitting on the end of the bed...  I mean I can explain that this is a one person only contraption, but I REALLY don't want it coming down regardless of what gets thrown at this thing. Any ideas, criticisms, feedback, will be so greatly appreciated.  I think this could be really awesome, and I know it will make my son flip out!  He's got a very small room, and this will free up so much space. Thanks again.  John

I'm thinkin of puttin together one o these. Think I'll go with counterweight instead of spring. Even the counterweight will act toward more momentum, assuming the fulcrum is sufficiently anchored.   Post by Samanyoluhaber.com.

Over the weekend, I built a trebuchet. It is two feet tall from base to arm, and it uses a 2.5 pound weight as a counterweight. It will only launch a golfball around 8 feet! It has barely any arc at all. Can somebody help?

The winner is a weight powered slingshot made by Hiyadudez. His explanation of how the gun fires; It's basically a normal gun rail, with a 'car' on the rail. Attached to the 'car' is string that runs to the front of the gun and over some pulleys. Attached to the other end of the string is a big weight/counterweight. When released, it pulls the car forward (the bullet is in front of the car) and sends it flying out of the barrel, but the car stays in. It shoots a blue rod 10-15 feet. Thanks to everyone who participated. The next contest can be found here.

One of my records is scratched, and I thought it was impossible to play through perfectly because of how scratched it is.  I found out today that it IS possible!  I found that by adjusting the tone arm to track more lightly, the record would paly over the scratches instead of following them.  Alas, there is a pop when the needle goes over the scratch, but a pop is better than a skipped section of a song.  My tone arm doesn't have a counterweight on it, so I MacGyvered a way to balance it; I taped a fifty-cent piece to the end of it on the top to make it track lighter.  If your record player is skipping, give this a try before you clean your record in hopes of getting rid of the scratch.  This way is a lot easier. 

Here's the deal: I'm working on a project that uses 2 motors (PS2 controller vibrating motor, without the counterweight), I assume these are 5v dc motors, right? Both rotate the same axis (1 is not enough due to the pressure that is being put on it, a spring mechanism stuff) With 12v it runs like a dream, till they burn! and from what I observed, always 1 motor hits higher temperature than the other, is there a problem with that? Then I dropped it to 5v with diodes and the motors didnt have the strenght to start spinning, so I raised to 8v and they spin, not very smoothly (is that spell right?), but you know, they work, but still they're overheating! If I used PWM to control both of the motors, would it work and not burn'em? Thanks and sorry for the long and confusing text.

Ok. I need to create a camera crane. It dosn't have to be very big since I'm using it for stop motion. Just a simple pan and tilt crane with a counterweight to off-set the camera. Now, I can make a regular one very simply using a video crane method that you can find on this site. However, this crane must do 2 things. 1. It must be able to move at incredibly small increments. Only fractions of an inch at a time. 2. The crane must be able to hold it's position in a very sturdy manner. It cannot move even in the slightest because stop-motion requires that the camera does not move at all while individual pictures are being taken. For the life of me, I can't figure it out. Traditionally, a "step motor" is used to create the individual movements for things like this. But they are incredibly expensive. I've had more luck with gears and servos, however I want to figure out the logistics before I just go buy gears individually on a website that may or may not work. Your help would be appreciated. Thank you.

Hey, I'm new on here but realllyyy need some help in this as I have a limited technological background. Basically I have a project in which have two digital displays, each one displaying either the time, in minutes or the hour (two digits per display). Now what I want to do with these is effectively attach these on to the hands of an analogue clock, so that when the hands spin round, the time is displayed. For example when the minutes hand is at the quarter past mark, the display will read 15 and when the hour hand is at the bottom the other display will read 06. So I have the designs ready for this clock (including counterweights and whatnot) but I just need a very powerful clock movement, or gearing system that will enable me to turn a couple of heavy clock hands, I have seen online you can but high torque movements which at the moment is my best bet, but i cant imagine it will work very well to be honest. I would really appreciate any response or something to point in the right direction as I'm very open minded and if the issue is solved, I will be sure to put up instructions on how this clock was made. Thanks for reading. Josh

I had an idea for a camera stabilizer a while ago which involves some basic rules of physics. I've done some thinking on it and I can't seem to figure out if it would really work or not. It involves two principles: 1.) Torque (t=f*d) 2.) Inertia (p=m*v) ---- The idea is to combine a gimbal design found on camera "gliders" like these: -Commercial product: http://www.bhphotovideo.com/c/product/521721-REG/Steadicam_MERLIN_Merlin_Camera_Stabilizing_System.html -Homemade design: http://www.diycamera.com/stabiliser/index.html ...with some sort of see-saw to counter the effects of up-and-down motion.  Ignoring the fact that this might be somewhat hard to hold such a thing, I just want to know if this would work. ---- Any balanced see-saw will have an equal amount of torque on either side of the pivot point. Therefore, a balanced see-saw will work with 500g hung 10cm from either side of the pivot point, OR 750g 5cm from one side and 250g 15cm from the other side (750*5=3750; 250*15=3750).  With this concept, I thought of designing this part of the stabilizer like a small camera jib (http://en.wikipedia.org/wiki/Jib_(camera)). That is, the camera on one end with a counterweight on the other. The pivot point would have a handle or some kind of vehicle mount on it.  The stabilization occurs (or so I'm thinking) because of inertia. Inertia=mass*velocity. So, when the pivot point (the handle) moves up or down, one of the sides of the see saw should move up faster than the other. The side that moves up slower (the longer side of the see saw, I'm thinking) should have the camera mounted to it.  ---- Is there a flaw somewhere in my thinking? THE QUESTION: Would both sides of an uneven length, balanced see-saw move up at the same time when the pivot point is moved up or down? I'm not really sure and I'd like to hear your input. 

[edit: this isn't real, but it would be awesome] In the interest of helping out our amazing community of authors, we’ve decided to make all of Instructables available for download in a single PDF document. That way when the EMPs hit or the grid goes down, you’ll have all the chicken rearing, solar paneling, rain barreling, wind turbining, and urban farming resources you’ll need. And because we’re including everything, you’ll also be able to stave off the post-apocalypse blues with bacon roses and unicorn poop. We’re putting all 127,000 Instructables projects into a single omnibus edition that will be sold at cost (TBD) to Instructables authors and for about $1000 for non-members. We’ll also make the PDF available to Pro members. If you’re so inclined, you can print and bind your own version. Get familiar with KaptinScarlet’s “How to Bind Your Own Hardcover Book” Instructable. We found a spectacular publisher who’s willing to bind the pages with paracord and baling wire. This edition should have just about 30 meters of paracord in the binding, along with just enough baling wire to keep the whole thing together if you choose to take out the paracord. The publisher also agreed to include a metal shank in the spine that can be fashioned into a makeshift knife, shovel, or bottle opener. The book is big enough to make a pretty nice counterweight for a small trebuchet, too. There were a few challenges for this publication. First of all, there’s an awful lot of content. To keep the print length down, we used small images wherever possible. We also cut the comment sections and individual project tables of contents. We did, however, keep the advertisements in the margins just in case AdSense will pay out during the End of Days. This publisher did balk at including packages of strike-anywhere matches in the book jacket. Sorry everybody. Matches were deemed “too unsafe” for their production and distribution teams. As though a conflagration of Amazon packages in the back of a UPS truck is less safe than losing a few digits to a frozen post-apocalyptic hellscape. The biggest challenge of all, though, was the sheer size of the book itself. The rough draft weighed in at about 500 kilograms. In a lucky break, using that ultra-thin biblical/lexicographer paper stock allowed us to cut the weight to just 220kg AND to make the pages double as bathroom tissue in a Charmin-less world. The tome will require a licensed forklift operator to receive it (or you can choose to pay the $150 white glove installation surcharge.) And, as usual, we cannot ship to a PO box.

I would like to build a few, properly working, ultrasonic devices.For example an ultrasonic soldering iron and an ultrasonic soldering bath.But some small ultrasonic plastic welder or cutter is nice too :)If you ever had one of the above to play with you know why they are great to have.The development story so far:I managed to destroy several driver boards.The ones you find for cheap with 28 or40kHz transducers in your favourite online store.In the beginning I knew I will have a need to repair or replace these boards but no clue why.Take an ultrasonic cleaner and read the manual.There it is always pointed out that a low water level can destroy your toy.What does that exactly mean?The transducer needs to be kept in resonance, if the water level is too low or something havy sits right at the bottom of the tank the frequency drifts off too much.Very expensive untis can cope a bit better here, which gave me the idea for the universal driver.During my experiments with hoorns I noticed that it is very hard to get usable results without extensive computer simulations first.Just one mm too long or too short and literally nothing happens, go a bit further and a thin aluminium horn might start to crack under the stress.And in all these cases the driver overloads, in one cheap case to the point that the transducer fused together.Trying to examine these driver circuits while they operate turned out to be a total nightmare!Place the probe from the ocsilloscope literally anywhere and the thing goes out of tune already.By the way: Never coil up the wires going to your transducer.....Only way I found that somehow works is by adding a tiny transformer around the wire going to the transducer and to measure the voltage generated there.To make it short: Destructive testing provided the requirements a driver needs to match to keep the cost low.Reasons for the premature death of cheap driver boards:Almost all of these cheap drivers I could find generate the 28 or 40kHz signal from the mains voltage.Means it goes through a transformer to get the desired 50-80V and some witchcraft turns that into a more or less smooth DC voltage.This is then switched by some beefy transistors, mosfets or similar, depending on the circuit.The actual feedback happens with a tiny ring toroid, similar to what you use to drive a ZVS system.With this dirt simple design a fully tuned transducer - like when nothing is attached to it yet - would cause the driver to provide a voltage of about 6x of what the transducer is rated for.Thankfully in most cases the transducer survives this a couple of times while the transistors fry within about 3 seconds no matter how good the cooling.Slightly out of tune - like when mounted onto a cleaning tank - the resonant frequency is slightly off the tuned 28 or 40kHz.The driver compensates this through the tiny feedback transformer.But this only goes for a about 1-4kHz, drift away further and first the power drops, then the voltage spikes and it dies.The feedback is not able to shift the generated frequency enough as it is ultimately derived from the mains frequency of your grid.Reasons why a dedicated, low cost driver would open new possibilities:Imagine you need to make a horn or sonotrode for your transducer.Knowing that each half of it should be equal to a quarter wavelength of the operating frequency is nice and easy.But if you add something like a blade for cutting or you need some pressure for welding then calculated dimensions become useless.Programs to fully simulate complex sonotrode designs, especially if you need to add screws or blades are costly and out of reach for most of us.Even if you would have access you still need to know the material properties to know the speed of sound in the material and how much it can flex in various directions without being subjected to metal fatigue.For basically all hobby needs in terms of ultrasonic gadgets we are happy with a simple push pull motion.the same motion our transducer offers by default.And when it comes to attachments it turned out that quite stubby horns of light weight are a good compromise already.A 50-50 ratio of diameter and length works reasonably well in most cases.For example the standard 40kHz transducer of 45mm diameter is quite happy to work with a horn like this:45mm diameter on the thick end, 20mm diameter on the tin end.Thick part 40mm long, thin part 42mm long.The extra 2mm are for the manual tuning by filing or sanding it off until there is good cavitation happening when you put the end into water.This however is only good for simple testing purposes and some fun but as soon as you attach blades or a small pot with about 200grams of molten solder the tuning is way off and destroys the driver quickly.To be able to deal with different pressure levels on the working end or just a different mass that is attached the driver needs to "know" the new self resonant frequency.Basic idea for a dedicated driver:Please bare with me on this one as my developing days got severly neglected once I moved to the other side of the globe....Input should from a 12V power supply, preferably a PSU to keep costs and sourcing time low.The operating voltage for the transducer shall come from a simple switch mode supply.I was thinking of scrapping a PSU for the transformer and switching transistor.This however would provide about 120-160V on 240V mains with the transformer of a PSU.To match the required load changes it would be great to drive this first transformer by PWM means to regulate the output voltage with a potentiometer while keeping it steady within the set values.Basically like every cheap phone charger but with an output voltage that can be adjusted and kept regulated.The switching transistors for the transducer should be well over the required specs of an out of tune transducer.I guess capable of switching 600V should be sufficient.Main design change to the cheap driver boards would be the feedback.A hall effect sensor could provide the proportional voltage to the current going into the transducer.It would also provide the real operating frequency of the transducer for the feedback loop.The resulting real resonant frequency of the running system is then used to drive the switching transistors.As a result the transducer would always be driven at the exact right frequency no matter the load on the working end.These transducers still have a quite limited frequncy range due to the fixed counterweight on the back - it is optimised to be self resonant without the transducer being mounted.To explain this feature let me use a spring with a weight on it....You can move your hand up and down to make the weight swing up an down with the spring force.You can also push the weight to get the same effect.But if the weight would just expand and contract there would be no change in the spring force or position or the weight.Our transducer however is mounted to something and the weight on the back is heavier than what is on the front end of the transducer.As a result the weight is pushed back and forth and because all is fixed together this movement is transfered to for example your cleaning bowl.Without anything attached to the transducer it would literally start to rip itself apart until either the bolt or the ceramics fail.The feedback loop needs to prevent this by adjusting the switching voltage going to the transducer.Once too far out the system needs to shut off until it can reset.The frequency control is not that fragile.With the power controlled through the feedback even a wide drift in the operating frequency of about 5kHz would only reduce the effectiveness and amplitude of the moving horn/sonotrode.Sadly my skill set in circuits is not that good anymore to have the required parts in my head and to know how to combine them properly :(Why this concept is only really good for really basic applications:Professional solutions utlise often less than 20W of ultrasonic power for a soldering iron or scaler.For these devices the sonotrode/horn is spefically designed for the task at hand.Same goes for any possible attachments - without them these things don't do much at all.Finding these low power ceramic transducer rings for a good price is hard enough, making an amplifying horn even harder.But when using these quite big 50 or 100W transducers we find for cheap online we can compensate the lower amplitude with the added power of the transducer.Since we only need surface action but won't have to go through a few liters of liquid it might even be beneficial.Fun fact: A 40kHz transducer has the second harminc frequency at about 170kHz.Means we could design a driver for the second harmonic and enjoy total silence when working with it.Would also mean that the ultrasonic power would be much higher.Mass times acceleration and such things ;)If you want some ultrasonic cutter then you don't want to waste weeks and lots of money trying to come up with a working attachment to your transducer.Just keep it as short as possible and with about the same weight as the front part of the transducer.At least the driver desing would make it quite easy to design an amplifying horn by trail and error through reducing the lenght of the thin end until it really fits.Anyone with good circuit skills willing to volunteer? ;)