A Digital Canvas That’s Hard to Spot

While sorely lacking in pictures of the innards of this digital canvas, we were extremely impressed with the work that went into making such a convincing object. [Clay Bavor] wanted a digital picture frame, but couldn’t find one on the market that did what he wanted. They all had similar problems, the LCDs were the lowest quality, they were in cheap bezels, they had weird features, they had no viewing angle, and they either glowed like the sun or were invisible in dark environments.

[Clay] started with the LCD quality, he looked at LCD specs for the absolute best display, and then, presumably, realized he lived in a world where money is no object and bought a 27″ iMac. The iMac has a very high pixel density, no viewing angle, and Apple goes through the trouble of color balancing every display. Next he got a real frame for the iMac, cut a hole in the wall to accommodate it, and also had a mat installed to crop the display to a more convincing aspect ratio for art. One of the most interesting part of the build is the addition of a Phidgets light sensor. Using this, he has some software running that constantly adjusts the Mac to run at a brightness that’s nearly imperceptible in the room’s lighting.

Once he had it built he started to play around with the software he wrote for the frame. Since he wanted the frame to look like a real art print he couldn’t have the image change while people were looking, so he used the camera on the Mac and face detection to make sure the image only changed when no one was looking for a few minutes. He also has a mode that trolls the user by changing the image as soon as they look away.

We admit that a hackier version of this would be tearing the panel out of a broken iMac and using a lighter weight computer to run all the display stuff. [Clay] reached the same conclusion and plans to do something similar for his version 2.0.

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Solderless Breadboard Parasitics

Solderless breadboards are extremely handy. You always hear, of course, that you need to be careful with them at high frequencies and that they can add unwanted capacitance and crosstalk to a circuit. That stands to reason since you have relatively long pieces of metal spaced close together — the very definition of a capacitor.

[Ryan Jensen] did more than just listen to that advice. He built a circuit and used a scope to investigate just how much coupling he could expect with a simple digital circuit. Better still, he also made a video of it (see below). The test setup shows a single gate of a hex Schmitt trigger inverter with a sine wave input. The output transitions ring and also couple back into the input.

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Shmoocon 2016: Efficient Debugging For OS X

Developers love their macs, and if you look at the software that comes with it, it’s easy to see why. OS X is a very capable Unix-ey environment that usually comes on very capable hardware. There is one, huge, unbelievable shortcoming in OS X: the debugger sucks. GDB, the standard for every other platform, doesn’t come with OS X and Apple’s replacement, LLDB is very bad. After crashing Safari one too many times, [Brandon Edwards] and [Tyler Bohan] decided they needed their own debugger, so they built one, and presented their work at last weekend’s Shmoocon.

Building a proper tool starts with a survey of existing tools, and after determining that GDB was apparently uninstallable and LLDB sucked, their lit review took a turn for the more esoteric. Bit Slicer is what they landed on. It’s a ‘game trainer’ or something that allows people to modify memory. It sort of works like a debugger, but not really. VDB was another option, but again this was rough around the edges and didn’t really work.

The problems with the current OS X debuggers is that the tools used by debuggers don’t really exist. ptrace is neutered, and the system integrity protection in OS X El Capitan has introduced protected locations that can not be written to by root. Good luck modifying anything in /Applications if you have any recent Mac.

With the goal of an easy-to-use debugger that was readily scriptable, [Brandon] and [Tyler] decided to write their own debugger. They ended up writing the only debugger they’ve seen that is built around kqueue instead of ptrace. This allows the debugger to be non-invasive to the debugged process, inject code, and attach to multiple processes at once.

For anyone who has every stared blankly at the ‘where is GDB’ Stack Overflow answers, it’s a big deal. [Brandon] and [Tyler] have the beginnings of a very nice tool for a very nice machine.

Hackaday at SCaLE 14x

Next weekend we’ll be at the fourteenth annual Southern California Linux Expo, a fantastic four-day event that covers everything from Apache to PHP, installing Ubuntu on old laptops, people who have their control key just to the right of their left hand pinky as god intended, and something about how much Linux sucks.

The event will feature 150 exhibitors, 130 sessions, tutorials, amateur radio tests, and features keynotes from Mark Shuttleworth, Cory Doctorow, and Sarah Sharp. It is the largest community-run open source and free software conference in North America.

The Hackaday crew will be there makin’ it rain stickers, but that’s not all: Supplyframe, the Hackaday overlords, is sponsoring Game Night at SCaLE. Saturday night will be filled with vintage video games, Nerf artillery, Settlers of Catan, Fireball Island (if someone can find it), and a hacker show and tell. This year is the inaugural SCaLE museum. The theme is Rise of the Machines: A Living Timeline, and will display historic engineering, computing devices, and clever gadgets.

If you’re in the area on Thursday, We’ll also be having a meet and greet at the soon-to-be-finished Supplyframe Design Lab in Pasadena. We only recently got the paperwork to have people in the space, so if you’d like to have a few drinks, have a few snacks, and look at a Tormach, come on over.

Basically, Its Minecraft

[SethBling] really likes Minecraft. How can you tell? A quick look at his YouTube channel should convince you, especially the one where he built a full-blown BASIC interpreter in Minecraft. It is not going to win any speed races, as you might expect, but it does work.

For novelty and wow factor, this is amazing. As a practical matter, it is hard to imagine the real value since there are plenty of ways a new programmer could get access to BASIC. Still, you have to admire the sheer audacity of making the attempt. One Hackaday poster (who shall remain nameless) once won a case of beer by betting someone he or she could write a BASIC compiler in BASIC, so we aren’t sticklers for practicality.

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Developed on Hackaday : HaDge update – it’s a HACK

Work on HaDge – the Hackaday con badge, continues in bits and spurts, and we’ve had some good progress in recent weeks. HaDge will be one conference badge to use at all conferences, capable of communicating between badges.

Picking up from where we left off last time, we had agreed to base it around the Atmel D21, a 32-bit ARM Cortex M0+ processor. To get some prototype boards built to help with software development, we decided to finish designing the HACK before tackling HaDge. HACK is a project that [Michele Perla] started that we have sort of assimilated to act as the prototyping platform for HaDge. We wanted a compact micro-controller board and hence opted for the SAM D21E – a 32 pin package with 26 IO’s.

[Michele Perla] had earlier designed HACK based on the larger 32 pin SAM D21G and used Eagle to hack-brddraw the schematic and layout. Using the Eagle to KiCad script, he quickly converted the project and got on to making the board layout. I took up the rear guard, and worked on making his schematic (pdf) “pretty” and building up a schematic library of symbols. While [Michele] finished off the board layout, I worked on collecting STEP models for the various footprints we would be using, most of which I could get via 3dcontentcentral.com. The few I couldn’t were built from scratch using FreeCAD. The STEP models were converted to VRML using FreeCAD. Using [Maurice]’s KiCad Stepup script, we were able to obtain a complete STEP model of the HACK board.

HACK is now ready to go for board fabrication and assembly. We plan to get about 20 boards made and hand them out to developers for working on the software. The GitHub repository has all the current files for those who’d like to take a look – it includes the KiCad source files, PDFs, gerbers, data sheets and images. The board will be breadboard compatible and also have castellated pads to allow it to be soldered directly as a module. Let us know via group messaging on the HACK project page if you’d like to get involved with either the software or hardware development of HaDge.

In a forthcoming post, we’ll put out ideas on how we plan to take forward HaDge now that HACK is complete. Stay tuned.

J.C. Bose and the Invention of Radio

The early days of electricity appear to have been a cutthroat time. While academics were busy uncovering the mysteries of electromagnetism, bands of entrepreneurs were waiting to pounce on the pure science and engineer solutions to problems that didn’t even exist yet, but could no doubt turn into profitable ventures. We’ve all heard of the epic battles between Edison and Tesla and Westinghouse, and even with the benefit of more than a century of hindsight it’s hard to tell who did what to whom. But another conflict was brewing at the turn of 19th century, this time between an Indian polymath and an Italian nobleman, and it would determine who got credit for laying the foundations for the key technology of the 20th century – radio.

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