Make A Bit Of Cloth With This 3D Printable Loom

July 25, 2017 by Jenny List 9 Comments

When the hackspace where this is being written created their textile room, a member who had previously been known only for her other work unexpectedly revealed herself to be a weaver, and offered the loan of a table-top loom. When set up, it provided an introduction to the art of weaving for the members of all different interests and backgrounds, and many of them have been found laying down a few lines of weft. It’s a simple yet compelling piece of making which captivates even people who might never have considered themselves interested in textiles.

If you are not lucky enough to have a friendly hackspace member with a spare loom when you wish to try your hand at weaving, you may be interested in this Thingiverse project, a 3D printable rigid heddle loom. It’s not the most complex of looms, the heddle is the part that lifts the warp threads up and down, and it being the rigid variety means that this loom can’t do some of the really fancy tricks you’ll see on other types of loom. But it’s a functional loom that will allow you to try your hand at weaving for the expenditure of not a lot of money, some 3D printer filament, and some PVC pipe. If your hackspace or bench has an area devoted to textiles, it may find a place.

We’ve shown you a few looms on these pages over the years, but mostly of the more mechanised variety. A Raspberry Pi automated loom for example, or a CNC Jacquard loom.

Thanks to our Shenzhen contributor-at-large, [Naomi Wu] for the tip.

Smart Gun Beaten By Dumb Magnets

July 25, 2017 by Michael Uttmark 221 Comments

[Plore], a hacker with an interest in safe cracking, read a vehemently anti-smart-gun thread in 2015. With the words “Could you imagine what the guys at DEF CON could do with this?” [Plore] knew what he had to do: hack some smart guns. Watch the video below the break.

Armed with the Armatix IP1, [Plore] started with one of the oldest tricks in the book: an RF relay attack. The Armatix IP1 is designed to fire only when a corresponding watch is nearby, indicating that a trusted individual is the one holding the gun. However, by using a custom-built $20 amplifier to extend the range of the watch, [Plore] is able to fire the gun more than ten feet away, which is more than enough distance to be dangerous and certainly more than the few inches the manufacturers intended.

Not stopping there, [Plore] went to the other extreme, creating what he calls an “electromagnetic compatibility tester” (in other words, a jammer) that jams the signal from the watch, effectively preventing a legitimate gun owner from firing their gun at 10 to 20 feet!

Not one to call it quits, [Plore] realised that the gun prevented illicit firing with a simple metal pin which it moved out of the way once it sensed the watch nearby. However, this metal just happened to be ferrous, and you know what that means: [Plore], with the help of some strong magnets, was able to move the pin without any electrical trickery.

Now, we’ve already covered the many hurdles that smart guns face, and this specific investigation of the state of smart gun technology doesn’t make the picture look any brighter. We’re aware that hindsight is always 20/20, so let us know in the comments how you would fix the problems with the Armatix IP1.
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Hackaday Prize Entry: USB Packet Snooping

July 25, 2017 by Brian Benchoff 34 Comments

Sometimes you run into a few problems when developing your own hardware, and to solve these problems you have to build your own tools. This is exactly how [KC Lee]’s USB Packet Snooper was created. It’s a small device that allows for capturing and analyzing Full Speed USB traffic to debug one of [KC]’s other Hackaday Prize entries.

[KC] is building an HID Multimedia Dial for this year’s Hackaday Prize. It’s kind of like the Microsoft Surface Dial or the ubiquitous Griffin PowerMate that has been on the market for the better part of two decades. This multimedia dial is bitbanging USB with an STM8, which means [KC] needs a tool to capture raw USB packets.

The design of this USB Packet Snooper is split up into two parts. The first is either a dongle or a pass-through device that simply serves as a tap between a USB device and a USB host. The logging and analysis board attaches to this dongle, and uses a rather fast ARM microcontroller to listen in on USB packets and send everything over serial to a PC.

This is a rather novel device; V-USB is limited to Low Speed USB, and other USB capture tools are far out of reach of the hobbyist budget. Software solutions on a PC obviously won’t work because [KC] doesn’t even know if he’s sending valid USB packets. This is a great tool that finally brings hobbyist-level USB analysis up to Full Speed USB.

KIM-1 To COSMAC Elf Conversion — Sort Of

July 25, 2017 by Al Williams 11 Comments

In the mid-1970s, if you had your own computer, you probably built it. If you had a lot of money and considerable building skill, you could make an Altair 8800 for about $395 — better than the $650 to have it built. However, cheaper alternatives were not far behind.

In 1976, Popular Electronics published plans for a computer called the COSMAC Elf which you could build for under $100, and much less if you had a good junk box. The design was simple enough that you could build it on a piece of perf board or using wire wrap. We featured the online archive of the entire Popular Electronics collection, but hit up page 33 of this PDF if you want to jump right to the article that started it all. The COSMAC Elf is a great little machine built around a 40-pin RCA 1802 processor, and for many was the first computer they owned. I lost my original 1802 computer in a storm and my recent rebuild in another completely different kind of storm. But there is a way to reclaim those glory days without starting from scratch. I’m going to repurpose another retro-computing recreation; the KIM-1.

I’ll admit it, Rewiring a real KIM-1 to take an 1802 CPU would be difficult and unnecessary and that’s not what this article is about. However, I did have a KIM UNO — [Oscar’s] respin of the classic computer using an Arduino mini pro. Looking at the keyboard, it occurred to me that the Arduino could just as easily simulate an 1802 as it could a 6502. Heck, that’s only two digits different, right?

The result is pretty pleasing. A “real” Elf had 8 toggle switches, but there were several variations that did have keypads, so it isn’t that far off. Most Elf computers had 256 bytes of memory (without an upgrade) but the 1802 UNO (as I’m calling it) has 1K. There’s also a host of other features, including a ROM and a monitor for loading and debugging programs that doesn’t require any space in the emulated 1802.

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Sunday: Breakfast At DEF CON

July 25, 2017 by Mike Szczys 6 Comments

Nurse your hangover by having Breakfast at DEF CON with Hackaday this Sunday. You’re invited to our yearly ritual by marking the beginning of the end with coffee and pastries at 10:30 am.

Choosing an exact location in advance is always tricky (anyone who’s been to DEF CON understands). We’ll pick a place once we hit town later this week. For now, head over to the Breakfast at DEF CON event page and hit the “join the team” button on the bottom left so we can let you know when we’ve found the perfect location for the breakfast meetup.

Extra internet points go to those who bring some hardware to show off… and especially for anyone who is making this the end of their Saturday rather than the beginning of Sunday. [Brian] and [Mike] will be there, joined by our friends [Jasmine] and [Shulie] who are on the scene for Tindie, a sponsor of the IoT Village this year. See you on Sunday!

How To Take Pictures Of PCBs

July 25, 2017 by Brian Benchoff 50 Comments

While we’ve covered light box builds and other DIY photography solutions, general picture-snapping tips and tricks are a bit out of the purview of what we normally write about. Nevertheless, [Alain] just put up a great tutorial for taking pictures of PCBs. This is a great skill to have — no one cares about what you’ve built unless you have a picture of it — and the same techniques can be applied to other small bits and bobs of electronic equipment.

As with all matters of photography, light is important. [Alain] built a DIY light box using two cheap outdoor square LED panels and some scrap wood. There’s really nothing to this build: just build a box that holds soft, diffused light.

A camera is a little more complicated than a box, and here [Alain] is using an entry-level DSLR with a kit lens. The takeaway here is to set the aperture to the highest number (or smallest hole) possible while still keeping a reasonable shutter speed. This increases the depth of field and produces a picture where the board and the tops of components are in focus.

There are a few more tips for getting the best PCB pics possible including shooting in RAW for Aperture or Lightroom, getting a macro lens, and using a tripod. Like all things, there’s a law of diminishing returns, and even with a smartphone camera and a DIY light box, you can produce some fantastic pics of PCBs.

Earth Ground And The Grid

July 25, 2017 by Steven Dufresne 46 Comments

The electrical grid transmits power over wires to our houses, and our Bryan Cockfield has covered it very well in his Electrical Grid Demystified series, but what part does the earth ground play? It’s commonly known to be used for safety, but did you know that in some cases it’s also used for power transmission?

Typical House Grounding System

A pretty typical diagram for the grounding system for a house is shown here, along with a few of the current carrying conductors commonly called live and neutral. On the far left is the transformer outside the house and on the far right is an appliance that’s plugged in. In between them is a breaker panel and a wall socket of the style found in North America. The green dashed line shows the normal path for current to flow.

Notice the grounding electrodes for making an electrical connection with the earth ground. To use the US National Electrical Code (NEC) as an example, article 250.52 lists eight types of grounding electrodes. One very good type is an electrode encased in concrete since concrete continues to draw moisture from the ground and makes good physical contact due to its weight. Another is a grounding rod or pipe at least eight feet long and inserted deep enough into the ground. By deep enough, we mean to include factors such as the fact that the frost line doesn’t count as a good ground since it has a high resistance. You have to be careful of using metal water pipes that seemingly go into the ground, as sections of these are often replaced with non-metallic pipes during regular maintenance.

Notice also in the diagram that there are places where the various metal cases are connected to the grounding system. This is called bonding.

Now, how does all this system grounding help us? Let’s start with handling a fault.

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