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Hackaday Links: November 3, 2024

“It was the best of times, it was the blurst of times?” Perhaps not anymore, if this Ig Nobel-worthy analysis of the infinite monkey theorem is to be believed. For the uninitiated, the idea is that if you had an infinite number of monkeys randomly typing on an infinite number of keyboards, eventually the complete works of Shakespeare or some other famous writer would appear. It’s always been meant to be taken figuratively as a demonstration of the power of time and randomness, but some people just can’t leave well enough alone. The research, which we hope was undertaken with tongue firmly planted in cheek, reveals that it would take longer than the amount of time left before the heat death of the universe for either a single monkey or even all 200,000 chimpanzees in the world today to type the 884,647 words of Shakespeare’s complete works in the proper order.

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Wearable Robot Makes Mountain Climbing A Breeze For Seniors

You know, it’s just not fair. It seems that even if we stay active, age will eventually get the better of our muscles, robbing them of strength and our bodies of mobility. Canes and walkers do not provide additional strength, just support and reassurance in a treacherous landscape. What people could really benefit from are wearable robots that are able to compensate for a lack of muscle strength.

[Dr. Lee Jongwon] of the Korea Institute of Science and Technology has developed this very thing. MOONWALK-Omni is designed to “actively support leg strength in any direction”, and make one feel like they are walking on the moon. In order to test the wearable robot, [Dr. Jongwon] invited senior citizens to climb Korea’s Mount Yeongbong, which is some 604 meters (1980 feet) above sea level.

The robot weighs just 2 kg (about 4.5 lbs) and can be donned independently by the average adult in under ten seconds. There are four high-powered but ultra lightweight actuators on either side of the pelvis that aid balance and boost leg strength by up to 30%. This is all designed to increase propulsion.

An AI system works to analyze the wearer’s gait in real time in order to provide up-to-the-second effective muscle support in many different environments. One wearer, a formerly active mountain climber, reported feeling 10-20 years younger when reaching the top of Mount Yeongbong.

It’s quite interesting to see mobility robots outside of the simplicity of the rehabilitation setting. We have to wonder about the battery life. Will everyone over 65 be wearing these someday? We can only hope they become so affordable. In the meantime, here’s a wearable robot that travels all over your person for better telemetry.

Robotic Biped Walks On Inverse Kinematics

Robotics projects are always a favorite for hackers. Being able to almost literally bring your project to life evokes a special kind of joy that really drives our wildest imaginations. We imagine this is one of the inspirations for the boom in interactive technologies that are flooding the market these days. Well, [Technovation] had the same thought and decided to build a fully articulated robotic biped.

Each leg has pivot points at the foot, knee, and hip, mimicking the articulation of the human leg. To control the robot’s movements, [Technovation] uses inverse kinematics, a method of calculating join movements rather than explicitly programming them. The user inputs the end coordinates of each foot, as opposed to each individual joint angle, and a special function outputs the joint angles necessary to reach each end coordinate. This part of the software is well commented and worth your time to dig into.

In case you want to change the height of the robot or its stride length, [Technovation] provides a few global constants in the firmware that will automatically adjust the calculations to fit the new robot’s dimensions. Of all the various aspects of this project, the detailed write-up impressed us the most. The robot was designed in Fusion 360 and the parts were 3D printed allowing for maximum design flexibility for the next hacker.

Maybe [Technovation’s] biped will help resurrect the social robot craze. Until then, happy hacking.

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Listen To Your Feet, They Have A Lot To Tell You

[Umar Qattan] is in tune with his sole and is trying hard to listen to what it has to say.

At a low level, [Umar] is building an insole with an array of force sensors in it. These sensors are affixed to a flexible PCB which is placed in a user’s shoe. A circuit containing a ESP32, IMU, and haptic feedback unit measure the sensors and send data back to a phone or a laptop.

What’s most interesting are the possibilities opened by the data he hopes to collect. The first application he proposes is AR/VR input. The feedback from the user’s feet plus the haptics could provide all sorts of interesting interaction. Another application is dynamically measuring a user’s gait throughout the day and exercise. People could save themselves a lot of knee pain with something like this.

[Umar] also proposes that an insert like this could record a user’s weight throughout the day. Using the data on the weight fluctuation, it should be possible to calculate someone’s metabolism and hydration from this data.

Cat Robot’s Secret To Slim Legs? Banish The Motors!

The first thing to notice about [Bijuo]’s cat-sized quadruped robot designs (link is in Korean, Google translation here) is how slim and sleek the legs are. That’s because unlike most legged robots, the limbs themselves don’t contain any motors. Instead, the motors are in the main body, with one driving a half-circle pulley while another moves the limb as a whole. Power is transferred by a cable acting as a tendon and is offset by spring tension in the joints. The result is light, slim legs that lift and move in a remarkable gait.

[Bijuo] credits the Cheetah_Cub project as their original inspiration, and names their own variation Mini Serval, on account of the ears and in keeping with the feline nomenclature. Embedded below are two videos, the first showing leg and gait detail, and the second demonstrating the robot in motion.

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Measuring Walking Speed Wirelessly

There are a lot of ways to try to mathematically quantify how healthy a person is. Things like resting pulse rate, blood pressure, and blood oxygenation are all quite simple to measure and can be used to predict various clinical outcomes. However, one you may not have considered is gait velocity, or the speed at which a person walks. It turns out gait velocity is a viable way to predict the onset of a wide variety of conditions, such as congestive heart failure or chronic obtrusive pulmonary disease. It turns out, as people become sick, elderly or infirm, they tend to walk slower – just like the little riflemen in your favourite RTS when their healthbar’s way in the red. But how does one measure this? MIT’s CSAIL has stepped up, with a way to measure walking speed completely wirelessly.

You can read the paper here (PDF). The WiGate device sends out a low-power radio signal, and then measures the reflections to determine a person’s location over time. Alone, however, this is not enough – it’s important to measure the walking speed specifically, to avoid false positives being triggered by a person simply not moving while watching television, for example. Algorithms are used to separate walking activity from the data set, allowing the device to sit in the background, recording walking speed data with no user interaction required whatsoever.

This form of passive monitoring could have great applications in nursing homes, where staff often have a huge number of patients to monitor. It would allow the collection of clinically relevant data without the need for any human intervention; the device could simply alert staff when a patient’s walking pattern is indicative of a bigger problem.

We see some great health research here at Hackaday – like this open source ECG. Video after the break.

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“Look Ma, No Gyros!”: A Self-Balancing Mechanical Velociraptor

You’ve got to walk before you can run, right? Perhaps not, if this bipedal dino-like running robot is any indication.

Officially dubbed a “Planar Elliptical Runner,” the bot is a test platform for bipedal locomotion from the Institute for Human and Machine Cognition. Taking inspiration from the gait of an ostrich — we think it looks more like a T. rex or velociraptor, but same difference — [Jerry Pratt]’s team at IHMC have built something pretty remarkable. Contrary to all the bipedal and quadrupedal robots we’ve seen, like Boston Dynamics’ Big Dog and PETMAN, which all fairly bristle with sensors and actuators, the PER is very stripped down.

A single motor runs the entire drive chain using linkages that will look familiar to anyone who has taken an elliptical trainer apart, and there’s not a computer or sensor on board. The PER keeps its balance by what the team calls “reactive resilience”: torsion springs between the drive sprocket and cranks automatically modulate the power to both the landing leg and the swing leg to confer stability during a run. The video below shows this well if you single-frame it starting at 2:03; note the variable angles of the crank arms as the robot works through its stride.

The treadmill tests are constrained by a couple of plastic sheets, but the next version will run free. It’s not clear yet how directional control will be achieved, not is it obvious how the PER will be able to stop running and keep its balance. But it’s an interesting advance in locomotion and we look forward to seeing what IHMC’s next trick will be.

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