The Square Inch Project

For the last few years, Hackaday has been putting together some amazing contests. We gave away a trip to space, but the winner took the money instead. We gave away another trip to space, but those winners took the money instead. But we had a ton of fun along the way and are glad to see some others are getting in on the action. In September, a contest appeared out of the blue on hackaday.io. It is the Square Inch Project, a contest with the goal of stuffing the most electronics on a square inch of printed circuit board.

This wasn’t a contest designed, planned, or organized by anyone in charge here; this is a completely organic competition arranged and implemented by the hackaday.io community. A few months ago, a few notable hackaday.io people just decided to have a contest. Awesome.

OSHPark was kind enough to give out credits for PCBs as prizes, a we added in a few gift certificates to the Hackaday Store. Apparently that’s all you need to get a lot of people making a lot of cool stuff.

There are a lot of really great entries – far too many to cover in a single post – but you’ll find a few great ones below.

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Beautiful Sidewalk Graffiti Machine

Our hero [Alex] just built a sidewalk graffiti machine, and it’s a beauty to behold, so make sure you check out the video below the break. But don’t neglect [Alex]’s blog, and the build videos throughout. (Nice t-shirt in the wheel-making video, BTW.)

The machine itself is basically a two-meter wide printer where the roller is replaced with drive wheels. The frame, made of plywood, looks great and helps keep the machine light weight. Everything is done with DC motors and timing belts, which means motor encoders and closed-loop control in the firmware. It connects via a WiFi serial bridge, made with an ESP8266, to [Alex]’s cell phone.

Everything, from plans to software, is available on [Alex]’s GitHub for the project.

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The Three Week Three Dollar Binary Watch

There’s a Maker Faire in three weeks, and your group wants to design and build a binary watch to give to attendees. You don’t have much time, and your budget is $3 per watch. What do you do? If you are [Parker@Macrofab] you come up with a plan, buy some parts, and start prototyping.

[Parker] selected the PIC16F527 because it had enough I/O and was inexpensive. A cheap crystal and some miscellaneous discrete parts rounded out the bill of materials. Some cheap ESD straps would serve for a band. He did the prototype with a PICDEM board and immediately ran into the bane of PIC programmers: the analog comparators were overriding the digital I/O pins. With that hurdle clear, [Parker] got the rest of the design prototyped and laid a board out in Eagle.

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Which SD Card To Use In A Pi?

There is surprising variation in the performance of SD cards. They are not all created equal and the differences can impact the running of your Raspberry Pi, no matter which model. [Jeff Geerling] wondered exactly how different cards would affect system performance. He ran a number of tests on cards ranging from cheap no-names to well-known brand names. The no-name cards fared pretty badly but even among the brand names there is considerable variation.

microsd-cards-all-tested-raspberry-pi

[Matt] over at Raspberry Pi Spy also tested SD cards and found similar differences. Both tested microSD cards. [Jeff’s] tests were solely on the Pi while [Matt’s] were on Windows 7, Ubuntu, and a Pi.

The discussions in the blog about what to measure were as interesting as the actual results. That lead to determining which software tools to use for the measurement. For example, a system doing a lot of small database reads and writes might work better with one SD card while a system storing and then streaming videos might work better with another card. Another interesting result is that the Pi’s data bus greatly limits the access speeds. [Jeff] measured much higher speeds running the same tests using a Mac with a USB dongle. The cards are capable of much more than the Pi can deliver.

[Matt] also checked the capacity of the SD cards. There are a lot of fakes floating around marked with higher capacities than they actually support. Even getting a brand name card may not help since some are counterfeit. So beware: if the price it too good to be true, it very well may be.

3D Scanning Entire Rooms With A Kinect

Almost by definition, the coolest technology and bleeding-edge research is locked away in universities. While this is great for post-docs and their grant-writing abilities, it’s not the best system for people who want to use this technology. A few years ago, and many times since then, we’ve seen a bit of research that turned a Kinect into a 3D mapping camera for extremely large areas. This is the future of VR, but a proper distribution has been held up by licenses and a general IP rights rigamarole. Now, the source for this technology, Kintinuous and ElasticFusion, are available on Github, free for everyone to (non-commercially) use.

We’ve seen Kintinuous a few times before – first in 2012 where the possibilities for mapping large areas with a Kinect were shown off, then an improvement that mapped a 300 meter long path though a building. With the introduction of the Oculus Rift, inhabiting these virtual scanned spaces became even cooler. If there’s a future in virtual reality, we’re need a way to capture real life and make it digital. So far, this is the only software stack that does it on a large scale

If you’re thinking about using a Raspberry Pi to take Kintinuous on the road, you might want to look at the hardware requirements. A very fast Nvidia GPU and a fast CPU are required for good results. You also won’t be able to use it with robots running ROS; these bits of software simply don’t work together. Still, we now have the source for Kintinuous and ElasticFusion, and I’m sure more than a few people are interested in improving the code and bringing it to other systems.

You can check out a few videos of ElasticFusion and Kintinuous below.

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Go From Prototype To Pilot Production With Zach Fredin

What’s it like to build a run of 100 prototypes in your basement? Get a first-hand account as [Zach Fredin] discusses his development and production of NeuroBytes. The system is a set of electronic models that represent neurons. Connecting them together into different networks helps to teach about how the human nervous system works. It’s a wonderful concept, and was recognized as a finalist for Best Product in the 2015 Hackaday Prize. More recently, [Zach] tells us it has been granted Recommended Status for a Phase I SBIR National Science Foundation grant. Looks like [Zach’s] new job is all NeuroBytes and is well funded. Congratulations!

Check out [Zach Fredin’s] talk from the 2015 Hackaday SuperConference, then join us after the break to dig further into the details of the project.

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Vintage Video Projector Lives Again

Projectors are getting a lot less expensive these days, what with China pumping out Pico projectors by the boat load and all. But did you know it’s not that hard to convert an old slide projector to digital? [Alec Smecher] shows us how with a 1950’s LaBelle 75 slide projector, and the result is pretty awesome.

dmd_chipDigital projectors can use a few different technologies to work. The best, and brightest is DLP (Digital Light Processing) by Texas Instruments — which is pretty well the world-wide standard for high-end, high-lumen digital projection. It works by bouncing red, green, and blue light off of three DMD’s (Digital Micromirror Devices) which have an array of tiny 2-position mirrors, with each representing a pixel.

One of the older technologies is LCD, which is even easier to understand. You shine white light through a color LCD, and there is your projection. All you need for a projector, then, is an LCD, a light source, and a bit of optics.

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