For their final project in embedded microcontroller class, [Aaheli, Jun, and Naomi] turned their focus toward assistive technology and created an Electronic Travel Aid (ETA) for the visually impaired that uses haptic feedback to report the presence of obstacles.
We have seen a few of these types of devices in the past, and they almost always use ultrasonic sensors to gauge distance. Not so with this ETA; it uses six VL53L0X time-of-flight (ToF) sensors mounted at slightly different angles from each other, which provides a wide sensing map. It is capable of detecting objects in a one-meter-wide swath at a range of one meter from the sensors.
The device consists of two parts, a wayfinding wand and a feedback module. The six ToF sensors are strapped across the end of a flashlight body and wired to an Arduino Mini inside the body. The Mini receives the sensor data over UART and sends it to the requisite PIC32, which is attached to a sleeve on the user’s forearm. The PIC decodes these UART signals into PWM and lights up six corresponding vibrating disc motors that dangle from the sleeve and form a sensory cuff bracelet around the upper forearm.
We like the use of ToF over ultrasonic for wayfinding. Whether ToF is faster or not, the footprint is much smaller, so its more practical for discreet assistive wearables. Plus, you know, lasers. You can see how well it works in the demo video after the break.
This device is intended to augment the traditional white cane, not replace it. This virtual cane we saw a few years ago is another story.
Continue reading “Find Your Way with Tiny Laser Beams”
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.
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.
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.
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.
Continue reading “Hackaday Prize Entry: Dynamometer for Post Stroke Rehabilitation”
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.
I’ve fallen and I can’t get up. We all remember it, and we all know what product we’re talking about. Now, with cheap microcontrollers, ubiquitous WiFi, and wearable electronics, there must be a simpler solution. [Jean Paradedel]’s emergency button project is designed to replace those wearable emergency buttons, which usually include an expensive call center plan.
[Jean]’s button is based off an ESP8266 module, which sends an email to a care provider if a button is pressed. The whole thing is powered by a CR2032 watch battery and the device’s case was 3D printed. The interface is simple — it’s just a wearable button, after all — and the form factor is small enough to be completely unobtrusive.
[Jean] reflashed the ESP8266 board with a simple sketch that runs the project. First, a button-press connects the device to WiFi and then blinks an LED so you know it’s connected. When the emergency button is pressed, an email is sent out letting a caregiver know that there’s a problem.
Check out the video below for a demo of this cheap emergency button in action.
Continue reading “Hackaday Prize Entry: Inexpensive Emergency Button”