assistive technolgy

25 Articles

This Servo Actuated Multimeter Does The Twist

February 14, 2020 by 9 Comments

This tip comes our way courtesy of [Elad Orbach], who’s been experimenting with a device that uses a servo to turn the function dial on a multimeter. It’s something you can put together in a few minutes with leftovers from the parts bin, and as you can see in the video after the break, the basic concept seems to be sound enough.

As to finding a practical reason for spinning the switch on your meter with a servo, that’s left largely as an exercise for the reader. [Elad] hints at the possibility of using such a setup to help automate repetitive testing, which we could see being useful especially in combination with a foot pedal that allows you to switch modes without having to put the probes down. The same basic idea could also be helpful as an assistive device for those who have difficulty grasping or limited dexterity.

Whether top of the line or bottom of the barrel, the multimeter is easily the hardware hacker’s most frequently used tool (beyond the screwdriver, perhaps). We’ve seen plenty of projects that try to graft additional features onto this common gadgets, though automation isn’t usually among them.

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Hackaday Prize Entry: UAProsthetics, A Powered Hand

October 10, 2017 by 6 Comments

One of the great successes of desktop 3D printers is custom prosthetics and orthotics. For a fraction of the price of a prosthetic arm, you can buy a machine capable of producing hundreds of completely customizable prosthetics. [Taran Ravindran]’s project in the running for the 2017 Hackaday Prize follows the long tradition of building customized prosthetics. His prosthetic hand designed to be simpler and cheaper than conventional artificial limbs while still giving us some innovation in how this hand will move.

The digits on [Taran]’s hand are controlled by linear servos pulling on a series of Bowden cables. One servo actuates the index finger, with a double differential to close the three less important figures — the middle, ring, and pinky fingers don’t need the articulation of the forefinger and thumb. Those three are actuated together, saving cost and complexity — they basically operate to support the index and thumb rather than being controllable independently. The thumb has 2 DOF by itself to give it the maximum amount of utility.

Another area of importance [Taran]’s focusing on is the matter of ease of use. If the prosthesis is too complicated, difficult, or unpleasant to use, it won’t get used regardless of its awesome features. Knowing this, he focused on making the hand as simplified as possible. Right now, the project has been modeled in CAD, and [Taran] is just waiting for the SLS parts to arrive before assembling the whole thing. It’s a great project, and a great entry for this year’s Hackaday Prize.

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Hackaday Prize Entry: Personal Guardian Keeps An Eye Out

October 8, 2017 by 14 Comments

The Personal Guardian is a wearable tracking and monitoring device intended to help vulnerable people. The project goal is to allow these patients as much independence and activity as possible without a caregiver needing to be present. Wearing a sensor package might allow a memory care patient (for instance) greater freedom to wander.

The device consists of an Arduino 101 development board with a GSM shield that it uses to send SMS messages to the caregiver — for instance, if the accelerometer shows the patient fell over, or moved beyond certain GPS coordinates. Furthermore, the care-giver can monitor the device to determine the device’s status, and sees the patient’s heart rate thanks to a BLE sensor strap.

The patient can also press a panic button or toggle through a series pre-set SMS messages. In terms of complexity, the project’s creator [Ray Lynch] intended the interface to be simpler than a smart phone.

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Hackaday Prize Entry: Economical Bionic Leg

October 6, 2017 by 9 Comments

When it comes to high-tech bionic legs for amputees, all the cool stuff is titanium, carbon fiber or other, more exotic materials. With carbon fiber “blades” all the rage, it’s easy to forget that simpler technologies still work, and could be made to work even better with the addition of some inexpensive electronics. The Economical Bionic Leg project is the result of that idea.

Project creators [PremJ20] and [G.Vignesh] aren’t kidding about bringing the cost of these bionic legs down. The target goal is $60 per, with stainless steel and silicon rubber as a cheaper alternative to carbon fiber — the rubber would be molded to fit the amputated region. The heart of the project is a Particle Photon development board, with a flex sensor and accelerometer monitoring the prosthesis and supplying data to the cloud. It’s essentially a basic prosthetic leg with a monitoring system built in. Placing a sensor cuff on the regular leg, the artificial limb’s flexibility can be fine-tuned to match the two.

Will this inexpensive bionic leg ever compete in the Olympics, like [Oscar Pistorious] run in the 2012 London event? Probably not — the tech that goes into artificial limbs has the same amount of material science going into it as F1 racing and turbojet design. Still, this is a very cheap way to bring tech into something that desperately needs to be cheaper, and it’s a great Hackaday Prize entry, to boot.

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Hackaday Prize Entry: Dynamometer For Post Stroke Rehabilitation

October 2, 2017 by 4 Comments

For those who have suffered a stroke, recovery is a long and slow process that requires rehabilitation to start as early as possible. Quite often, secondary stroke attacks complicate matters. Spasticity — muscle contraction and paresis — muscular weakness, are two of the many common after-effects of stroke. Recovery involves doing repeated exercises to strengthen the muscles and bring back muscle memory. Benchmarking progress becomes difficult when caregivers are only able to use qualitative means such as squeezing tennis balls to monitor improvement. To help provide quantitative measurements in such cases, [Sergei V. Bogdanov] is building a Dynamometer for Post-Stroke Rehabilitation. It is an Open Source, 4-channel differential force gauge for measuring and logging the progress of the patient. The device measures, graphs, and logs the force exerted by the four fingers when they push down on the four force gauges.

The device consists of four strain gauges obtained from cheap kitchen scales. The analog outputs from these are fed to HX-711 24-bit ADC boards. An Arduino Nano processes the data and displays it on two banks of eight-digit LED modules. [Sergei] also experimented with a 20×4 character LCD in place of the LED display. In the standalone mode, the device can only indicate the measured forces on the LED (or LCD) display which is calibrated to display either numerical values or a logarithmic scale. When connected to a serial port and using the (Windows only) program, it is possible to not only view the same information but also save it at regular, set intervals. The data can also be viewed in graphical form.

The project page provides links to their Arduino code, Windows monitor program as well as build instructions. Check out the related assistive technology project that [Sergei] is working on — A Post Stroke Spasticity Rehab Helper.

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Hackaday Prize Entry: Visioneer Sensor HUD

September 28, 2017 by 4 Comments

Only about two percent of the blind or visually impaired work with guide animals and assistive canes have their own limitations. There are wearable devices out there that take sensor data and turn the world into something a visually impaired person can understand, but these are expensive. The Visioneer is a wearable device that was intended as a sensor package for the benefit of visually impaired persons. The key feature: it’s really inexpensive.

The Visioneer consists of a pair of sunglasses, two cameras, sensors, a Pi Zero, and bone conduction transducers for audio and vibration feedback. The Pi listens to a 3-axis accelerometer and gyroscope, a laser proximity sensor for obstacle detection within 6.5ft, and a pair of NOIR cameras. This data is processed by neural nets and OpenCV, giving the wearer motion detection and object recognition. A 2200mA battery powers it all.

When the accelerometer determines that the person is walking, the software switches into obstacle avoidance mode. However, if the wearer is standing still, the Visioneer assumes you’re looking to interact with nearby objects, leveraging object recognition software and haptic/audio cues to relay the information. It’s a great device, and unlike most commercial versions of ‘glasses-based object detection’ devices, the BOM cost on this project is only about $100. Even if you double or triple that (as you should), that’s still almost an order of magnitude of cost reduction.

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