Hackaday Prize Entry: DIY Foot Orthotics

July 1, 2016 by 7 Comments

What does your gait look like to your foot? During which part of your gait is the ball of your feet experiencing the most pressure? Is there something wrong with it? Can you fix it by adding or removing material from a custom insole? All these answers can be had with an expensive system and a visit to a podiatrist, but if [Charles Fried] succeeds you can build a similar system at home. 

The device works by having an array of pressure sensors on a flat insole inside of a shoe. When the patient walks, the device streams the data to a computer which logs it. The computer then produces a heat map of the person’s step. The computer also produces a very useful visualization called a gait line. This enables the orthotist to specify or make the correct orthotic.

[Charles]’s version of this has another advantage over the professional versions. His will be able to stream wirelessly to a data logger. This means you can wear the sensor around for a while and get a much more realistic picture of your gait. Like flossing right before the dentist, many people consciously think about their gait while at the foot doctor; this affects the result.

He currently has a prototype working. He’s not sure how long his pressure sensors will last in the current construction, and he’s put wireless logging on hold for now. However, the project is interesting and we can’t wait to see if [Charles] can meet all his design goals.

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HALT In The Name Of Testing

July 1, 2016 by 16 Comments

“Did I forget something?” It’s that nagging feeling every engineer has when their project is about to be deployed – it may be a product about to be ramped into production, a low volume product, or even a one off like a microsatellite. If you have the time and a few prototypes to spare though, there are ways to alleviate these worries. The key is a test method which has been used in aerospace, military, and other industries for years – Highly Accelerated Life Testing (HALT).

How to HALT

The idea behind HALT testing can be summed up in a couple of sentences:

  • Beat your product to death.
  • Figure out what broke.
  • Fix it, and fix the design.
  • Repeat.

Sounds barbaric, and in many cases it is. HALT testing is often associated with giant test chambers which are literally designed to torture anything inside them. Liquid nitrogen shock cools the chamber as low as -100°C. The Device Under Test (DUT) can soak at that temperature for hours. Powerful heaters then blast the chamber, causing temperature rises of up to 90°C per minute, topping off at up to 200°C. Pneumatic hammers beat on the chamber table causing vibrations at up to 90 Grms and 10 KHz. Corrosive sprays simulate years of rain and humidity. These chambers are literally hell on earth for any device unlucky enough to be placed inside them. It’s easy to see why this sort of testing is often referred to as “Shake and Bake”.

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Hackaday Prize Entry: An MRI Machine

June 30, 2016 by 27 Comments

Magnetic resonance imaging devices are one of the most fantastically incredible machines humans have ever built. They’re capable of producing three-dimensional images of living tissue by flipping protons around with a magnetic field. Ninety percent of the population doesn’t know what that sentence means, yet you can find an MRI machine inside nearly any reasonably equipped hospital in America.

For his Hackaday Prize entry, [Peter Jansen] is building a magnetic resonance imager, capable of producing the same type of images you’d get from the radiology department at a hospital. It’s going to be a desktop unit, capable of scanning fruit and other similarly sized objects, and can be built using tools no more advanced than a hot air gun and a laser cutter.

This project is a continuation of what should have been [Peter]’s Hackaday Prize entry last year. Things got busy for him last summer, he dropped out of the Hackaday Prize, which means he’s welcome to continue his build this year.

Last year, [Peter] developed the plywood mechanism that would rotate a magnetic sensor across the diameter of the scanning volume, rotate the object to be scanned, and lift the object through the volume. It’s a weird 3-axis CNC machine, basically, but the parts near the magnetic sensor can’t be made out of metal. Dental floss worked okay, but we have a few hundred feet of Spectra fishing line if we ever bump into [Peter]. Magnetic resonance imaging means big coils of wire, too, which means the tedious task of winding coils around a cylinder is part of the build. [Peter] built a machine to do the work for him.

This is not [Peter]’s first attempt at building an imaging device. He built a desktop CT scanner that is exceptionally slow, but does shoot radiation through fruit to produce an image. His first project on Hackaday.io was the Open Source Science Tricorder, one of the top five finalists in the first year of the Hackaday Prize.

Already, [Peter] has some amazing work under his belt that produces real data that could not be otherwise obtained. An Open Source MRI is the perfect project for the Hackaday Prize’s Citizen Science phase, and we’re very happy to see him enter this project.

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Hackaday Prize Entry: Invisible

June 29, 2016 by 20 Comments

[Kate Reed] found a quote by a homeless person that said “No one sees us”, which led her to exploring what it actually means to be invisible — and if we actually choose to be invisible by hiding away our emotions, sexual preference, race or income. She realized that too often, we choose to only see what we want to see, rendering all the rest invisible by looking away. Her public art campaign and Hackaday Prize entry “Invisible” aims to increase social awareness and strengthening the community by making hidden thoughts, feelings and needs visible.

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Hackaday Prize Entry: A Universal Glucose Meter

June 28, 2016 by 77 Comments

If you need an example of Gillette’s razor blade business plan, don’t look at razors; a five pack of the latest multi-blade, aloe-coated wonder shaver is still only about $20. Look a glucose meters. Glucose meters all do the same thing – test blood glucose levels – but are imminently proprietary, FDA regulated, and subsidized by health insurance. It’s a perfect storm of vendor lock-in that would make King Gillette blush.

For his Hackaday Prize entry, [Tom] is building what was, until now, only a dream. It’s a universal glucometer that uses any test strip. The idea, of course, is to buy the cheapest test strip while giving the one-fingered salute to the companies who release more models of glucometers in a year than Apple does phones.

As with any piece of consumer electronics, there are plenty of application guides published by the biggest semiconductor companies explaining to engineers how to use their part to build a device. After reviewing the literature from TI, Maxim, Freescale, and Microchip, and a few research articles on the same subject, [Tom] has a pretty good idea how to build a glucometer.

The trick now is figuring out how to build an adapter for every make and model of test strip. This is more difficult than it sounds, because some test strips have two contacts, some have three, some have five, and all of them are proprietary. Calibration will be an issue, but if you’re building a glucometer from scratch, that’s not a very big problem.

This is one of the most impressive projects we’ve seen in this year’s Hackaday Prize. No, it shouldn’t be the only way a diabetic tracks their sugar levels, but diabetics shouldn’t rely only on test strips anyway. If you’re looking for a Hackaday Prize project that has the potential to upend an industry, this is the one.

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AVR Vs PIC, Round 223: Fight!

June 28, 2016 by 91 Comments

Get ready to rumble! [Thierry] made the exact same Hello-World-esque project with two microcontrollers (that are now technically produced by the same firm!) to see how the experience went.

It’s not just an LED-blinker, though. He added in a light-detection function so that it only switches on at night. It uses the Forest Mims trick of reverse-biasing the LED and waiting for it to discharge its internal capacitance. The point is, however, that it gives the chip something to do instead of simply sleeping.

Although he’s an AVR user by habit, [Thierry] finds in favor of the PIC because it’s got a lower power draw both when idling and when awake and doing some computation. This is largely because the PIC has an onboard low-power oscillator that lets it limp along at 32 kHz, but also because the chip has a lower power consumption in general. In the end, it’s probably a 10% advantage to the PIC on power.

If you’re competent with one of the two chips, but not the other, his two versions of the same code would be a great way to start familiarizing yourself with the other. We really like his isDarkerThan() function which makes extensive use of sleep modes on both chips during the LED’s discharge period. And honestly, at this level the code for the two is more similar than different.

(Oh, and did you notice [Thierry]’s use of a paper clip as a coin-cell holder? It’s a hack!)

Surprisingly, we’ve managed to avoid taking a stray bullet from the crossfire that occasionally breaks out between the PIC and AVR fans. We have covered a “shootout” before, and PIC won that round too, although it was similarly close. Will the Microchip purchase of Atmel calm the flames? Let’s find out in the comment section. We have our popcorn ready!

Hackaday Prize Entry: MyComm Handheld Satellite Messenger

June 27, 2016 by 54 Comments

We live in a connected world, but that world ends not far beyond the outermost cell phone tower. [John Grant] wants to be connected everywhere, even in regions where no mobile network is available, so he is building a solar powered, handheld satellite messenger: The MyComm – his entry for the Hackaday Prize.

The MyComm is a handheld touch-screen device, much like a smartphone, that connects to the Iridium satellite network to send and receive text messages. At the heart of his build, [John] uses a RockBLOCK Mk2 Iridium SatComm Module hooked up to a Teensy 3.1. The firmware is built upon a FreeRTOS port for proper task management. Project contributor [Jack] crafted an intuitive GUI that includes an on-screen keyboard to write, send and receive messages. A micro SD card stores all messages and contact list entries. Eventually, the system will be equipped with a solar cell, charging regulator and LiPo battery for worldwide, unconditional connectivity.

2016 will be an interesting year for the Iridium network since the first satellites for the improved (and backward-compatible) “Iridium NEXT” network are expected to launch soon. At times the 66 Iridium satellites currently covering the entire globe were considered a $5B heap of space junk due to deficiencies in reliability and security. Yet, it’s still there, with maker-friendly modems being available at $250 and pay-per-use rates of about 7 ct/kB (free downstream for SDR-Hackers). Enjoy the video of [Jack] explaining the MyComm user interface:

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