A Webcam Based Posture Sensor

May 6, 2014 by 9 Comments

Webcam based posture sensor

Even for hobby projects, iteration is very important. It allows us to improve upon and fine-tune our existing designs making them even better. [Max] wrote in to tell us about his latest posture sensor, this time, built around a webcam.

We covered [Max’s] first posture sensor back in February, which utilized an ultrasonic distance sensor to determine if you had correct posture (or not). Having spent time with this sensor and having received lots of feedback, he decided to scrap the idea of using an ultrasonic distance sensor altogether. It simply had too many issues: issues with mounting the sensor on different chairs, constantly hearing the clicking of the sensor, and more.  After being inspired by a very similar blog post to his original that mounted the sensor on a computer monitor, [Max] was back to work. This time, rather than using an ultrasonic distance sensor, he decided to use a webcam. Armed with Processing and OpenCV, he greatly improved upon the first version of his posture sensor. All of his code is provided on his website, be sure to check it out and give it a whirl!

Iteration leads to many improvements and it is an integral part of both hacking and engineering. What projects have you redesigned or rebuild? Let us know!

3D Printed Cast With Ultrasound Emitter Promises Faster Healing Times

May 6, 2014 by 44 Comments

3dcast-640x426

Almost a year ago, [Jake Evill] broke his hand stopping a fight between his friend and another person. And over the next few weeks he realized how archaic  plaster casts really are — clunky, smelly, itchy — not exactly conducive to healing, other than by keeping your arm completely immobilized. That’s when he came up with the Cortex Cast — a 3D printed exoskeleton cast that provides support, allows your arm to breath, and can even get wet!

Fast forward to today, and another designer is playing with 3D printed casts — but ones that could potentially speed up the healing time! Turkish designer [Deniz Karasahin] heard about a system called the Exogen, which is a low-intensity ultrasound system which can help speed up bone repair, sometimes up to 38% faster. The problem? It doesn’t really work well with regular casts, because the transducer needs to touch the skin — the solution? A 3D printed cast of course!

You see, the ultrasound tech has been around for over 20 years, but has never really seen mainstream use because the difficulties in actually using it, until perhaps now.

Better yet, they’re also hoping to launch trials in the US soon — 3D printers are only good for trinkets and doodads? Pfft.

[Thanks William!]

A Low Cost, Solar-Powered Swamp Cooler

May 5, 2014 by 53 Comments

A looming, torturous summer is preparing to bear down on many of us, making this dirt-cheap swamp cooler build an attractive hack to fend off the heat.

Though this is a pretty standard evaporative cooler, the design comes together in a tidy and transportable finished product. The base is a ~$3, 5-gallon bucket from a local hardware store with its accompanying Styrofoam liner. Three 2 1/8″ holes carved into the side of both the bucket and liner will snugly fit some inch-and-a-half PVC pipe with no need for glue.

One last cut into the lid to seat a small desk fan rounds off this build—or you can chop into the styrofoam liner’s lid if you prefer. The video demonstrates using a 15W solar panel to run the fan, and we have to admit that the cooler seems to be an excellent low-cost build. It does, however, require a frozen gallon jug inside to pump out the chilled air for around 5-6 hours per jug. Maybe one of our frugal and mathematically-inclined readers can throw out some guesstimations for the cost of stocking the bucket with a jug of frozen water a couple times a day? Video after the jump.

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Recycled Foam Box Is Now A Weather Station

May 5, 2014 by 20 Comments

Raspberry pi in foam box

When [Ioannis] received some high resolution LCD’s in a tattered foam box, he posed to himself a most interesting question – Should he throw the foam box away, or use it as a container for a project? Fortunately for us, he decided on the latter and threw together a very capable weather station!

Having only an hour to spare, [Ioannis] grabbed a Raspberry Pi, WiFi USB stick and a camera module and went to work. He mounted the camera module to the foam lid using a highly advanced technique, and soldered a cable that would power the device directly to D17 – a Zener diode that sits on the bottom of the board.

For the weather data, he’s using another design of his – the Sensor Stick. This nifty device — which we featured over the weekend — is about the size of a stick of chewing gum, and sports an array of sensors including the popular BMP085, which can measure pressure and temperature .

He wraps up everything using open source software to get the data from the weather station. Pretty impressive for an old foam box and an hours time! This would be an interesting start to a home automation system. Connect it to motorized windows and/or a sprinkler system and he’s on his way to claiming The Hackaday Prize.

Bacon Alarm Clock Won’t Burn Your House Down

May 5, 2014 by 20 Comments

Bacon Alarm Clock

If you have trouble waking up in the morning then maybe this alarm clock is for you. A bacon-aroma-releasing alarm clock!

Fueled by her love of bacon, Instructable’s user [llopez2005] decided she wanted to try making an alarm clock that would actually get her out of bed, hungry, and ready for bacon. Instead of trying to design a clock that would actually cook bacon — which might be a bit dangerous — she’s found an extract of bacon aroma which she could slowly release instead.

The clock makes use of an Arduino Uno with a RTC shield as well as a LED array for the clock’s display. The “bacon” is actually made out of bake-able clay, which sits on top of unscented wax, infused with the bacon aroma oil. The bacon and “bacon grease” sit in a baby frying pan over top of a small heater element designed for warming candles. Before the alarm goes off, a SSR turns on the element which slowly melts some of the wax, releasing its ever so delicious scent.

What we really like about the clock is the level of detail she put into its appearance. The base is designed after a small wood burning stove they have in the house, and she’s even made a Plexiglas display case for the frying pan — with holes to let the aroma out though of course!

Boost Peak Power Tracking Battery Charger

May 5, 2014 by 25 Comments

[Rusdy] is building a solar charger for his electric bike, and quickly realized the lithium cells in his bike wouldn’t work well with the most common charge controllers out there. Solar cells have an IV curve, of course, and this changes with the amount of sunlight, requiring some conversion circuitry. Most of the charge controllers out there operate in buck mode, but the commercial boost mode converters [Rusdy] needed for his 36V battery are pricey as all get out. What was [Rusdy] to do? Build his own Boost MPPT solar charger, of course.

The circuit used for the charge circuit is fairly similar to a boost converter, with a little bit of logic required to get the maximum power out of the solar cells. [Rusdy] had an Arduino lying around, so that took care of the logic, and by sampling the voltage and current with the analog pins, he can turn a MOSFET on and off to get the most out of his solar cells.

The finished product works perfectly with an efficiency greater than 87%. Charging current and the final trickle charge is adjustable through software, allowing [Rusdy] to get the most out of his solar panels and electric bike. The board itself is just a prototype and could use a layout revision, but we’ve got to hand it to him for cloning a >$300 charge controller with an Arduino and a few scraps in a part drawer.

 

2014 Imagine RIT: An Innovation And Creativity Festival In Rochester, NY

May 5, 2014 by 14 Comments

Metal Imagine RIT Sign

Every year, the Rochester Institute of Technology hosts Imagine RIT, an innovation and creativity festival “that showcases the innovative and creative spirit of RIT students, faculty and staff.” The festival is free to the public and really brings the community together to celebrate technology, science, art, innovation, and creativity! We had the chance to attend this weekend and we had a blast looking at all of the engineering projects on display.

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