If you use just about any modern command line, you probably understand the idea of pipes. Pipes are the ability to connect the output from one program to the input of another. For example, you can more easily review contents of a large directory on a Linux machine by connecting two simple commands using a pipe:
ls | less
This command runs ls and sends its output to the input of the less program. In Linux, both commands run at once and output from ls immediately appears as the input of less. From the user’s point of view it’s a single operation. In contrast, under regular old MSDOS, two steps would be necessary to run these commands:
ls > SOME_TEMP_FILE
less < SOME_TEMP_FILE
The big difference is that ls will run to completion, saving its output a file. Then the less command runs and reads the file. The result is the same, but the timing isn’t.
You may be wondering why I’m explaining such a simple concept. There’s another type of pipe that isn’t as often used: a named pipe. The normal pipes are attached to a pair of commands. However, a named pipe has a life of its own. Any number of processes can write to it and read from it. Learn the ways of named pipes will certainly up your Linux-Fu, so let’s jump in!
Cyclic redundancy codes (CRC) are a type of checksum commonly used to detect errors in data transmission. For instance, every Ethernet packet that brought you the web page you’re reading now carried with it a frame check sequence that was calculated using a CRC algorithm. Any corrupted packets that failed the check were discarded, and the missing data was detected and re-sent by higher-level protocols. While Ethernet uses a particularly common CRC, there are many, many different possibilities. When you’re reverse-engineering a protocol that contains a CRC, although it’s not intended as a security mechanism, it can throw a wrench in your plans. Luckily, if you know the right tool, you can figure it out from just a few sample messages.
A case in point was discussed recently on the hackaday.io Hack Chat, where [Thomas Flayols] came for help reverse engineering the protocol for some RFID tags used for race timing. Let’s have a look at the CRC, how it is commonly used, and how you can reverse-engineer a protocol that includes one, using [Thomas’] application as an example.
If for some reason I were to acknowledge the inevitability of encroaching middle age and abandon the hardware hacker community for the more sedate world of historical recreation, I know exactly which band of enthusiasts I’d join and what period I would specialise in. Not for me the lure of a stately home in Regency England or the Royal court of Tudor London despite the really cool outfits, instead I would head directly for the 14th century and the reign of King Edward the Third, to play the part of a blacksmith’s wife making nails. It seems apposite to pick the year 1337, doesn’t it.
Why am I so sure? To answer that I must take you to the British Library, and open the pages of the Holkham Bible. This is an illustrated book of Biblical stories from the years around 1330, and it is notable for the extent and quality of its illuminations. All of mediaeval life is there, sharply observed in beautiful colour, for among the Biblical scenes there are contemporary images of the people who would have inhabited the world of whichever monks created it. One of its more famous pages is the one that caught my eye, because it depicts a woman wearing a blacksmith’s apron over her dress while she operates a forge. She’s a blacksmith’s wife, and she’s forging a mediaeval carpenter’s nail. The historians tell us that this was an activity seen as women’s work because the nails used in the Crucifixion were reputed to have been forged by a woman, and for that reason she is depicted as something of an ugly crone. Thanks, unknown mediaeval monk, you really don’t want to know how this lady blacksmith would draw you! Continue reading “Making A Mediaeval Nail”→
For the past few months we’ve been running this series of Blacksmithing For The Uninitiated posts, exploring the art of forge work for a novice. It’s based upon my experience growing up around a working blacksmith’s business and becoming an enthusiastic if somewhat inexpert smith, and so far we’ve spent our time looking at the equipment you might expect to need were you embarking on your own blacksmith work. Having assembled by now a basic forge of our own it’s now time to fire it up and take to the anvil for our first bit of smithing.
Lighting a forge is easy enough. Some people do it with a gas torch, but I break a piece of firewood into sticks using a hammer with the fuller set in the hardy hole on the anvil as an impromptu splitter. Making a small fire by lighting some paper under my pile of sticks placed on the hearth next to the tuyere I start the blower and then pile coke on top of the resulting conflagration. After about ten minutes I will have a satisfying roar and a heap of glowing coals, and as they burn there will be some slag collecting in the bottom of the fire that I will eventually need to rake out. Continue reading “Blacksmithing For The Uninitiated: Your First Time At The Anvil”→
The artistic elite exists in a stratum above we hoi polloi, a world of achingly trendy galleries, well-heeled collectors, and art critics who act as gatekeepers to what is considered the pinnacle du jour of culture. Artistic movements that evolve outside this bubble may be derided or ignored as naive and unsophisticated, even in complete denial of their raw creative edge. When they are discovered by the establishment a few of their artists are selected and anointed, while inevitably the crucible in which they were formed is forgotten. On the streets of Bristol the incredible work of far more graffiti artists can be seen than just that of Banksy.
Our community has an art form all of its own, in the guise of PCB artwork and the #BadgeLife community. One day you will see electronic badges from darlings of the art world behind glass in those trendy galleries, but for now they live in glorious abundance in the wild. Here at Hackaday we are lucky enough to have in Brian Benchoff a colleague who is pushing the boundaries of PCB art, and at the Hackaday Superconference he took us through one of his more recent pieces of work.
Brian’s pad printer.
The colour palette of a typical printed circuit board is limited by the combination of fibreglass, copper, soldermask, plating, and silkscreen its designer selects. Thus while the variety of soldermask colours and plating materials can make for an eye-catching work, they have remained a colour-tinted near monochrome. The Holy Grail of the PCB artist has been to step into the world of full colour, and Brian has been pursuing that goal by exploring pad printing to produce extra colours beyond the sodermask..
It’s a subject he’s written about here in the past, and he introduces it in the talk with a look at existing badge artwork and a mention of an expensive commercial inkjet process before considering the type of printing you see daily on the sides of promotional pens. Those company titles are deposited on pens using pad printing, an offset process in which ink is first deposited upon a photo-etched metal plate before being picked up on a silicone rubber pad for transfer to the object to be printed. It’s not the panacea for all coloured-PCB tasks, but for adding relatively small blocks of pigment to an otherwise monochromatic board it can be very successful.
The eye-catching Kiss -themed Tindie badges.
Brian’s examples are a panelised set of Tindie badges as a homage to the rock band Kiss, and his Tide pod addon containing a serial number in an EEPROM that was part of a Blockchain-inspired game. The Kiss Tindie badges use black soldermask with extensive white silkscreen and a modest area of red pad printing for the stage makeup, while the Tide addon makes clever use of the same swoosh printed in alternate colours at 180 degrees to each other.
In both cases there is some labour involved in creating the prints, and as his detailed write-up of printing the Tide pods reminds us, the process of creating the printing plate is not exactly an easy one. But it remains the best way yet to add extra colours to a board without paying a small fortune for the inkjet process, and if you’d like to put your own designs at the bleeding edge of PCB art you might wish to read his writeups and watch the video below the break.
This is just one example of the kind of manufacturing techniques, and electronic design principles on display at the Hackaday Superconference. There’s another Supercon just around the corner, so grab your ticket and send in your own talk proposal right away!
When I went to a hacker camp in the Netherlands in February I was expecting to spend a few days in a comfortable venue with a bunch of friends, drink some beer, see a chiptune gig, and say “Ooh!” a lot at the exciting projects people brought along. I did all of those things, but I also opened the door to something unexpected. The folks from RevSpace in the Hague brought along their portable forge, and before long I found myself working a piece of hot rebar while wearing comically unsuitable clothing. One thing led to another, and I received an invite to come along and see another metalworking project of theirs: to go form ore to ornamental technology all in one weekend.
From Dirt To Space is a collaboration between Dutch hackerspaces with a simple aim: to take iron ore and process it into a component that will be launched into space. The full project is to be attempted at the German CCCamp hacker camp in August, but to test the equipment and techniques a trial run was required. Thus I found myself in a Le Shuttle car transporter train in the Channel Tunnel, headed for the Hack42 hackerspace in Arnhem where all the parties involved would convene.
Regular readers will recognise this as the third part of a series exploring blacksmithing for those who have perhaps always fancied having a go but have never quite known where to start. It’s written from a position of the unusual experience of having grown up around a working forge, my dad may now be retired but he has a blacksmith specialising in architectural ironwork.
So far in this series we’ve looked in detail at the hearth and anvil that you might find in a typical forge, and delivered some pointers as to where you might look to find or even construct your own.Those are the signature pieces of equipment you’ll find in a forge, but with them alone you can still not be a blacksmith.
If I Had A Hammer…
An array of hammers of different weights and types.
Given an anvil, a hearth, and a vat of water to quench hot work in, and you’re almost set for your forge, but not quite. Most of a modern blacksmith’s workshop is the standard metalworking assortment of welders and angle grinders, but there is a set of tools that remain essential for blacksmithing alone. Your hammers are what connect you to the work, and can be as individual as the preferences of the blacksmiths themselves. There is no “right” answer to the question of what hammer you should use, instead you should use the one that works best for you. I instinctively favour a round-faced ball-peen hammer because that’s what my dad mostly used, but for example my Dutch friends use square faced cross-peen hammers. Blacksmiths will often make their own hammers to suit their needs, for example my dad made more than one using the high-quality steel of vehicle half-shafts as a starting point. Hardening them is a specialist skill in its own right, and I remember quite a few experiments before he perfected it.
It may well be stating the obvious, but the weight of the hammer influences how much energy it can impart to the work, and in turn the size of work that can be done. Casting an eye over my dad’s hammers the three workaday weights were 2 pound, 3 pound, and 4 pound (roughly 1 kg, 1.5 kg, and 2 kg), allowing a variety from fine work to heavier hitting of larger pieces. In a recent project, making a mediaeval nail, I selected an unsubtle lump hammer to draw out the larger square stock, and a much smaller one to finish it up, create the fine point, and relatively thin head. These are only a subsection of the hammers at his disposal though, like most blacksmiths he has a variety for all tasks, up to sledgehammers. I have frequently taken my turn either holding a piece with tongs while he used a sledgehammer, or on the sledgehammer myself.
Tongs, for Hot Gripping Moments
A selection of tongs, including some designed for very specific tasks. Our thanks to [Igor Nikolic] for making this picture possible.The constant companion to a blacksmith’s hammer is a pair of tongs. These can be bought from blacksmith’s suppliers, but making a pair can be a task within the reach of most smiths. Two identical sides are made from pieces of stock, with long thin handles, a flat piece to form the hinge, and whatever jaw piece is required. It feels like cheating to form the hole for the hinge on a drill press rather than on the anvil with a punch, but riveting it with a short piece of bar is a straightforward enough process. Blacksmiths will have a huge array of tongs with different jaws for specific jobs, built up over years as jobs demand it. If you cast your mind back to the Finnish smith pictured halfway down the first installment of this series, you’ll find several racks of tongs. A later episode of this series will look at making a set of tongs, though we can’t promise in advance the quality of the finished article.
A final moment for today should be spent on the subject of protective equipment. The hazards of blacksmithing are relatively uncomplicated, but some basic protective clothing is still very much worth having. The most obvious hazard is heat, you will be working in a noisy environment with red hot metal and fire. Though you will generate fewer sparks than you’d expect, I have a blacksmith’s leather apron and a set of fire-resistant overalls. Both of these are readily available from blacksmith’s supply stores, and are well worth the investment. There are also a lot of heavy and sharp items involved, not to mention hot particles on the floor. For that reason I also have a set of steel-toecapped workboots rated for hot particles. They aren’t the most elegant of footwear, but they have saved me from a few nasty moments.
I do not have any face protection specifically for blacksmithing, but depending on the work in hand there may be some sparks created. A polycarbonate face shield rated for hot particles should be available from any safety equipment supplier, and shouldn’t cost too much, and is an essential thing to own if you are doing any grinding or rotary wire brushing. Beyond that, there are also leather gloves designed for handling hot metal. I don’t use them because I prefer the feel of the hammer directly and am happy to use a pair of tongs to hold hot pieces of steel.
We’ve taken you through the basic workshop equipment of a blacksmith over the last few episodes of this series, and you should now have a basic idea of the safety kit you would be well advised to own. From this foundation we’ll next take you into the forge and start looking at a few blacksmithing techniques and simple projects, and along the way we’ll see some of the materials involved, too.
![A selection of tongs, including some designed for very specific tasks. Our thanks to [Igor Nikolic] for making this picture possible.](https://hackaday.com/wp-content/uploads/2019/04/tong-selection.jpg)
