Building An Accurate Equal Arm Balance

microscale

This interesting take on weights and measures uses a two foot long level as the base for a diy equal arm balance. The balance is the oldest method used for measuring mass. That’s because you don’t even need a reference weight for it to work as long as you are measuring ingredients that are proportional to each other in whole numbers.

The key to accuracy with these scales is to reduce friction at the fulcrum. In this case the fulcrum is made of two upturned razor blades on the base, with a single razor blade resting perpendicular to those on the arm. But because gravity is doing the equalization, the base must be as level as possible. Adjustable feet were added to the base so that it can be leveled on two axes. When the tower at the center was built (using threaded rod) a disc level was used to fine-tune the mounting angle of the two razor blades. The finishing touches include a coupling nut on each end for fine-tuning the balance, and the halves of a tea ball strainer as the weighing vessels.

 

This Cube Is Made For Walkin’

cubli

Meet Cubli, a research project which aims to make a cube that can walk around without using any appendages. It’s a research project at the Institute for Dynamic Systems and control in Switzerland. Anyone else thinking about our beloved companion cube right now?

The robotic experiments are based on angular momentum. Inside of the cube there are center mounted motors which each spin a wheel. Three of these are mounted perpendicular to each other to give the cube the ability to change its position along any axis. This is best shown by the first video after the break where just a single side of the assembly is demonstrated. A square frame starts at a rest position. You see the wheel spin up and it is suddenly stopped, which causes the momentum of the wheel to pop the square frame up onto one corner. The wheel then switches into a second mode to keep it balancing there. The final mode is a controlled fall. This theoretically will let the cube move around by falling end over end. So far they’re not showing off that ability, but the second demo video does show the assembled cube balancing on one corner.

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Printing And Programming A Self-balancer

The Hackaday staff isn’t in agreement on 3d printers. Some of us are very enthusiastic, some are indifferent, and some wonder what if they’re as widely useful as the hype makes them sound. But we think [Jason Dorweiler’s] self balancing robot is as strong a case as any that 3d printing should be for everyone!

Don’t get us wrong. We love the robot project just for being a cool self-balancer. Seeing the thing stand on its own (video after the break) using an Arduino with accelerometer and gyroscope sensors is pure win. But whenever we see these we always think of all the mechanical fabrication that goes into it. But look at the thing. It’s just printed parts and some wooden dowels! How easy is that?

Sure, sure, you’ve got to have access to the printer, it needs to be well calibrated, and then you’ve got to make the designs to be printed out. But these hurdles are getting easier to overcome every day. After all, there’s no shortage of people to befriend who want nothing more than to show off their Makerbot/RepRap/etc.

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The Bicycle Can Tell Us How To Make It Better

Over the years bicycle design has changed. Materials were upgraded as technology advanced, and accumulated knowledge helped bicycle builders make improvements along the way. But deep analysis with the intent to make meaningful improvements has not been widely embraced. Reasearchers at UC Davis are looking to expand into this frontier by letting the bicycle tell us how it can be improved. This is one of the test bikes they’ve been working on, which is mainly aimed at data harvesting. They’re hoping to find some real improvements based mostly on how the machine can get out of the rider’s way as much as possible. The thought here is that the rider’s body makes up 80-90% of the volume of the vehicle and should be accommodated in every way possible.

Sure, this could be a case of trying to build a better mouse trap. But listening to the discussion in the video after the break really drives home the complex issues of stability and locomotion that go into these seemingly simple vehicles. We’re going to guess the final recommendations will not involve making the bike five times taller.

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Android Legs Stability Testing

This is [James’] latest android build, a set of legs that use gyroscopes for balance.

He started off by planning the build with some LEGO pieces to get an idea of how each foot and leg joint would fit together. This let him achieve one of his goals. From the start he wanted to create a robot that would remain stable, and not build up enough momentum to tip itself over if there is a problem. With the dimensions established he cut out parts from 2mm sheets of HIP plastic using a hobby knife. They work in conjunction with a frame made from aluminum and HDPE. The whole thing houses eight servos responsible for movement, but he found an interesting way to use them for balance as well.

[James] came across some gyroscopic sensors which are made for use with RC helicopters. They connect in-line with a servo motor and offset it based on the gyro data. He’s using four of them with this bot, playing the hip and ankle servos against each other for balance. What results is a set of legs that look like their jonesin’ for a fix. See for yourself in the clip after the break.

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Watch Out Segway, Here Comes Tilto

tilto_demo

While the Segway enjoyed a few years of fame before falling off the radar, [Marcelo Fornaso] is hoping his creation has quite a bit more staying power. Inspired by the Segway’s ability to balance itself, he started thinking about how the concept could be improved. He felt that one of the Segway’s shortcomings arose out of the fact that the base platform was rigid and required the user to lean back and forth outside the device’s frame in order to turn it. He thought that this made the riding experience uncomfortable as well as risked causing the rider to fall over.

His creation, the Tilto, aims to both improve on the turning ability of the Segway while eliminating the need for handlebars. Based on a tilting mountain board design he had been tossing around for a while, the Tilto uses accelerometers and gyros to keep its balance, much like the Segway. His goal was to keep the vehicle balanced while traveling forwards and backwards, but also allowing the device to tilt from side to side without tipping over. This design keeps the rider mostly upright, allowing the user to direct the vehicle by leaning much like you would on a bicycle.

As you can see in the video below, the Tilto works pretty well, even in its prototype form.

Finally, a people mover that lets us get our gangsta lean on!

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Teaching Children To Walk Using Video Games

team_equiliberator

Medical conditions that prevent individuals from being able to walk are difficult to handle, even more so if the patient happens to be a child. Shriner’s hospitals treat a good number of children suffering from cerebral palsy, spina bifida, or amputations. They are always looking for creative treatment methods, so their Motion Analysis Laboratory looked to some Rice University undergrads for help. They asked the group of engineers to design a system that would make physical therapy a bit more fun, while helping encourage the children along.

The team recently unveiled their project, called the Equiliberator. The game system incorporates a series of five Wii balance boards situated between a pair of pressure-sensitive handrails. The platform communicates with a computer via Bluetooth, registering the patient’s movements as he or she moves along the path. The software portion of the system consists of a monster-slaying game which requires the child to step on a particular section of the pathway to dispose of the oncoming enemies.

The game is designed to get more difficult as the child’s balance and coordination improve, encouraging them with an ever growing bank of points as they progress. The final goal of the project is to enable the pressure sensitive handrails to determine how much the child is relying on them for balance, offering in-game incentives to walk with as little support as possible.

We love seeing hacks like this which not only entertain, but truly help people in the process. Kudos to the team at Rice University – they have done a fantastic job here.

Continue reading to see a quick video describing the Equiliberator in the designers’ own words.

[via MedGadget]

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