Month: December 2014

Flash Memory Endurance Testing

December 4, 2014 by 21 Comments

[Gene] has a project that writes a lot of settings to a PIC microcontroller’s Flash memory. Flash has limited read/erase cycles, and although the obvious problem can be mitigated with error correction codes, it’s a good idea to figure out how Flash fails before picking a certain ECC. This now became a problem of banging on PICs until they puked, and mapping out the failure pattern of the Flash memory in these chips.

The chip on the chopping block for this experiment was a PIC32MX150, with 128K of NOR Flash and 3K of extra Flash for a bootloader. There’s hardware support for erasing all the Flash, erasing one page, programming one row, and programming one word. Because [Gene] expected one bit to work after it had failed and vice versa, the testing protocol used RAM buffers to compare the last state and new state for each bit tested in the Flash. 2K of RAM was tested at a time, with a total of 16K of Flash testable. The code basically cycles through a loop that erases all the pages (should set all bits to ‘1’), read the pages to check if all bits were ‘1’, writes ‘0’ to all pages, and reads pages to check if all bits were ‘0’. The output of the test was a 4.6 GB text file that looked something like this:
Continue reading “Flash Memory Endurance Testing” →

Cutting Glass With CNC

December 4, 2014 by 33 Comments

Breaking a pane of glass in half is easy – just score it, break it, and after practicing a few times, you’ll eventually get it right. What about cuts that are impossible with a normal glass cutter, like radiused corners and holes? For that, you’ll need CNC. Yes, you can cut glass on a CNC machine. All you need is a diamond burr or glass drilling bit, high speeds, low feeds, and lots and lots of coolant.

Cutting glass on a CNC machine doesn’t require any spectacularly specialist equipment. [Peter] is using an $800 Chinese mini CNC engraver for this project, but that’s not the only tool that was required. A fixture for holding a glass plate was also needed, but [Peter] quickly fabricated one out of acrylic.

Cutting glass with a CNC is something we’ve seen before. [Ben Krasnow] has been using diamond burrs, high speeds, low feeds, and lots of coolant to cut mirrors so expensive you don’t even want to guess.

While [Peter] isn’t getting the perfect finish [Ben] got a few years ago, he’s still milling holes and slots in glass. He’s wondering if it could be possible to mill an aspheric lens using this technique and a special spherical burr, something that would be very interesting to see, and could be a pretty good way to rough out telescope blanks.

Serial Camera, Courtesy Of The STM32F4

December 4, 2014 by 47 Comments

Look around for a small, embedded camera module, and you’ll find your options are rather limited. You have the serial JPEG cameras, but they’re rather expensive and only have VGA resolution. A Raspi, webcam, and power supply is a false economy. GoPros are great, but you’re still looking at some Benjamins used.

The guys at GHI Electronics are taking a different tack. They’re using image sensors you would normally find in cellphones and webcams, adding a powerful ARM processor, and are still able to sell it for about $50. It’s called the ALCAM, and they’ve stumbled upon a need that hasn’t been met by any manufacturer until now.

On board the ALCAM is an OV3640 3-Megapixel image sensor. On the back of the board is a STM32F4 and a microSD card slot. The board can be set up for time-lapse videos, stop motion animation, or all the usual serial board camera functions, including getting images over a serial connection.

The ALCAM operates either connected to a PC though a 3.3V serial adapter cable, through a standalone mode with pins connected to a button or sensor, to the SPI bus on a microcontroller, or a serial to Bluetooth or WiFi bridge. Images can be saved to the uSD card, or sent down the serial stream.

It’s a pretty cool board, and if you’re thinking it looks familiar, you’re right: there’s a similar DSI camera/STM32F4 board that was an entry to The Hackaday Prize. Either way, just what we need to get better cameras cheaper into projects.

Penguin Binoculars

Happy Meal Hack Produces A Google Cardboard Test

December 3, 2014 by 27 Comments

Ever since Google Cardboard came out, [Julian Jackson] had been meaning to give it a shot. Affordable virtual reality? Who wouldn’t! But, he never got around to it — until one day he was sitting in McDonald’s with his son, explaining to him how the latest Happy Meal toy worked — it was a pair of penguin binoculars.

Fast forward past Thanksgiving and Black Friday and [Julian’s] son had completely forgotten about the McDonald’s toy in all the excitement, so [Julian] asked if he could have it. His son was mildly confused, but curious also, so he let his dad take his toy.

After attempting to dismantle it with a screw driver to get at the lenses, [Julian] carefully calculated the best place to simply break it without damaging them. With the precision of a heart surgeon he swung back his trusty hammer…  Continue reading “Happy Meal Hack Produces A Google Cardboard Test” →

Philly Fixers Guild Will Teach You How To Fish

December 3, 2014 by 16 Comments

One crisp Saturday afternoon a couple of weeks ago, the Philly Fixers Guild held its second Repair Fair. Not second annual, mind you; the first fair was held in September. People came from miles around, hauling with them basement and attic treasures that needed, well, fixing. [Fran] is one of the Guild’s volunteer fixers, and she shot some video of the event which is waiting for you after the break.

The Philly Fixers Guild aims to promote sustainability in the surrounding community by teaching interested parties to repair their possessions that might otherwise end up in a landfill. The fairs are not meant to be a drop-off repair site—attendees are expected to stay and learn about what’s wrong with their item and how it can or can’t be fixed.

The Guild is open to volunteers who are interested in teaching people how to fish, as it were. Expertise is not limited to electronics repair; guild members are just as interested in teaching people how to sew a replacement button on their winter coat or building that thing they bought at IKEA.

Nowhere near Pennsylvania? Several groups like the Philly Fixers Guild have already been established in a few larger US cities. If you’re not near any of those either (and we can sympathize), you could do worse than to start your own. If you’re part of a ‘space, creating such a guild would be a good way to spread the word about it and the gospel of DIY.

In the video, [Fran] discusses an Atari 2600’s control problem with its owner. She re-seats the 6532 RIOT chip and explains that this may or may not have solved the problem. If not, [Fran] is confident that new old stock chips are available out there on the hinterwebs. There might still be some landfill carts on ebay if the owner gets it up and running. [Fran] also fixes the controls on a Peavey amp and gets some Pink Floyd to issue forth from a previously non-functioning Zenith portable AM/FM radio that’s old enough to have a snap cover.

Continue reading “Philly Fixers Guild Will Teach You How To Fish” →

Geopolymer Concrete, Perfecting Roman Technology Today

December 3, 2014 by 48 Comments

For all the things Romans got wrong (lead pipes anyone?) did you know we’re still using a less advanced concrete than they did? Consider some of the massive structures in Rome that have passed the test of time, lasting for more than 2000 years. The typical concrete that we use in construction starts to degrade after only 50 years.

Researchers at Berkeley think they’ve finally figured it out with thanks to a sample that was removed from the Pozzuoli Bay near Naples, Italy. This could vastly improve the durability of modern concrete, and even reduce the carbon footprint from making it. The downside is a longer curing time, and resource allocation — it wouldn’t be possible to completely replace modern cement due to the limited supply of fly ash (an industrial waste product produced by burning coal). Their research can be found in a few articles, however they are both behind pay walls.

Lucky for us, and the open source community at large, someone from MIT has also been working on perfecting the formula — and he’s shared his results thus far.

So, who wants to give it a shot? Any material scientists in our midst?

Pico-Kubik Quadruped Fits In The Palm Of Your Hand

December 3, 2014 by 6 Comments

Most of the legged robots we see here are of the hexapod variety, and with good reason. Hexapods are very stable and can easily move even if one or more of the legs has been disabled. [Radomir] has taken this a step farther and has become somewhat of an expert on the more technically difficult quadruped robot, building smaller and smaller ones each time. He has been hard at work on his latest four-legged creation called the Pico-Kubik, and this one will fit in the palm of your hand.

The Pico-Kubik runs Micropython on a VoCore board, which allows for it to have a small software footprint to complement its small hardware footprint. It accomplishes the latter primarily through the use of HK-282A Ultra-Micro Servos, an Arduino Pro Mini, and a tiny lithium ion battery. It’s still a work in progress, but the robot can already crawl across the tabletop.

This isn’t [Radomir]’s first time at the tiny quadruped rodeo, either. He has already built the Nano-Kubik and the µKubik, all of which followed the first (aptly-named) Kubik quadruped. Based on the use of SI prefixes, we can only assume the next one will be the hella-Kubik!