Open Source Finger Prosthesis

October 18, 2012 by Mike Szczys 9 Comments

Here’s a project that is striving to develop a set of open source finger prosthesis. They are aimed at patients who have partial amputations. This means that part of the digit remains and can be used as the motive force behind a well designed mechanical prosthesis like you see above. This uses levers, pulleys, and wire to move a gripper in much the same way the pad of a pointer finger works. There’s even a video (embedded after the jump) which shows it being used to grab a toothpick from a dispenser… pretty impressive. This is similar to the prosthesis we saw in August which managed to work without pulleys and wire.

This isn’t limited to fingers. The same posts that shows off the unit seen above also includes a prosthetic thumb. The leverage for that design is provided by a woven nylon strap which attaches to a bracelet on the wrist.

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Unlocking Silk For Uses As An Optical, Digital, Biological, Or Food Storage Device

October 18, 2012 by Mike Szczys 10 Comments

[Fiorenzo Omenetto] gave a TED talk early last year to illustrates a lot of intriguing uses for silk. Before watching his presentation we would have been hard pressed to come up with a use for silk other than in clothing. But it turns out that investigating how silk worms create the material has led to a range of other applications. You can see the full talk embedded after the break.

One of the first things he shows off is a transparent film made of silk. The material looks almost like cellulose film, and can function in a similar way. [Fiorenzo] shines a laser through a silk slide that has a micro-dot of words embedded in it. the result is a clearly readable message projected on the wall. The film can also be used for holographic images.

But it’s the biodegradable aspects that are clearly the breakthrough here. A slide of silk can be doped with pharmaceuticals and programmed for a very specific time release. This way the drugs no longer need to be stored under refrigeration, and can be reclaimed using only water. The same properties allow one to manufacture disposable objects that will quickly and completely degrade. But there’s even more, if you dope the material with a conductor like gold it becomes a disposable circuit.

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Measuring A Pulse With Infrared Light

September 13, 2012 by Brian Benchoff 18 Comments

The next time you’re unfortunate enough to make your way to a hospital, emergency room, or urgent care clinic, you’ll be asked to attach a small pulse monitor to your finger. The device the nurses clip on to one of your remaining digits is called a photoplethysmographic sensor, and basically it is able to read your pulse through reflected light. In the search to find out how these devices actually work, [Raj] sent in a great tutorial covering the theory behind photoplethysmographicy, and also built a simple device to detect a pulse without using a microcontroller.

These photoplethysmographic sensors operate by shining light into someone’s flesh – usually a finger or ear lobe – and recording the light reflected back to the source. The volume of blood in the finger will have an effect on the amount of light reflected back, and makes for a perfect way to automatically measure someone’s heart rate.

To build his device, [Raj] used a TCRT1000 reflective optical sensor. Inside this sensor is an infrared LED and a phototransistor. Of course with a finger over the sensor there is a ton of noise both from ambient light and the base rate of reflected light from a piece of flesh. [Raj] filtered this out, leaving only the small variations in the amount of reflected light, thus creating a very simple – and very inexpensive – electronic pulse meter.

Mind-controlling Cockroaches

September 10, 2012 by Mike Szczys 81 Comments

Producing micro robotics is not yet easy or cost-effective, but why do we need to when we can just control the minds of cockroaches? A team or researchers from North Carolina State University is calling this augmented Madagascar Hissing cockroach an Insect Biobot in their latest research paper (PDF). It’s not the first time the subject has come up. There have already been proofs in research and even more amateur endeavors. But the accuracy and control seen in the video after the break is beyond compare.

The roach is being controlled to perfectly follow a line on the floor. One of the things that makes this iteration work so well is that the microcontroller includes a new type of ADC-based feedback loop for the stimulation of the insect brain. This helps to ensure that the roach will not grow accustom to the stimulation and stop responding to it. Since this variety of insect can live for about two years, this breakthrough makes it into a reusable tool. We’re not sure what that tool will be used for, but perhaps the next plague of insects will be controlled by man, and not mother nature.

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Genetic Research On The Cheap

September 9, 2012 by Eric Evenchick 12 Comments

When you think of DIY hardware, genetic research tools are not something that typically comes to mind. But [Stacey] and [Matt]’s OpenPCR project aims to enable anyone to do polymerase chain reaction (PCR) research on the cheap.

PCR is a process that multiplies a specific piece of DNA a few million times. It can be used for many purposes, including DNA cloning and DNA fingerprinting for forensics. PCR is also used for paternity testing.

The process involves baking the DNA at specific temperatures for the right amount of time. The DNA is first denatured, to split the helix into individual strands. Next, the temperature is lowered and primers are bound to the strands. Finally, another temperature is used to allow the polymerase to duplicate the DNA. This process is repeated to multiply the DNA.

The OpenPCR uses an Arduino to control a solid state relay. This relay provides power to two large resistors that act as heaters. A MAX31855 is used to read a thermocouple over SPI and provide feedback for the system. A computer fan is used to cool the device down.

A milled aluminium sample holder houses and heats the samples during cycling. The laser cut, t-slot construction case features some helix art, and houses all of the components. It will be interesting to see what applications this $85 PCR device can perform.

Via Adafruit

Can A Robot Be A Safe And Cost-effective Alternative To Guide Dogs?

September 5, 2012 by Mike Szczys 34 Comments

[Tom Ladyman] is making the case that a robot can take the place of a guide dog. According to his presentation, guide dogs cost about £45,000 (around $70k) to train and their working life is only about six years. On the other hand, he believes that this robot can be put into service for about £1,000 (around $1500). The target group for the robots is blind and visually impaired people. This makes since, because the robot lacks a dog’s ability to assist in other ways (locating and returning items to their companion, etc.). The main need here is independent travel.

He starts with the base of an electric wheelchair — a time-tested and economy-of-scale platform. The robot navigates based on images from four downward facing cameras mounted on the pole seen above. The X on the top of the pole allows for a much wider range of sight. The robot identifies its companion via a tag on their shoe, but it’s got another trick up its sleeve. The cameras feed to a set of four BeagleBoards which work together to process them into a 3D map at about 12 FPS, allowing for obstacle avoidance.

Check out the video after the break for a bit more information. The 3D guidance system is also explained in detail at the link above.

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Replacing A Finger Or An Arm In The Hacker Tradition

August 31, 2012 by Mike Szczys 33 Comments

Just a few weeks ago we were wondering if we’d try to build our own prosthesis if we were ever to lose a limb. This pair of hacks answers that query with a resounding “YES!”.

To the right is a replacement pointer finger. The missing digit took the first two knuckles with it, but there’s enough left to easily interface with this creation. It’s a mechanically clever assembly that moves as you would expect the original to. See for yourself after the break. It seem the maker intended to mold silicone around the structure but never got around to posting an update video.

On the left we have a chinese man who lost his arms while fishing. It seems they were using homemade bombs instead of nets and one went off prematurely. Since then he’s constructed several different prosthetic arms, each with its own special purpose. This one has a saw connected to it but these two write ups on the man show images of him using a fork and wielding a hammer.

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