Planet Nottinghack

12 October 2017

Martin Raynsford hackergotchi for Martin Raynsford

Vacuum Bed


The vacuum former came supplied with a wire mesh in the bottom of the bed. This lifts the item you're forming off the bed stopping it from blocking the vacuum hole. I decide to make myself a new vacuum bed that fills the area snugly and has a more uniform arrangement of holes. Thankfully the laser cutter is very good at making sheets of holes. I cut it out of 5mm acrylic, a sheet full of holes was held aloft on smaller dots that allow plenty of air flow under it. My thinking was that although the acrylic will eventually warm up I'm only heating the plastic for a minute or two and the plastic sheet provides a perfectly smooth surface. I was wrong, after I vacuum formed half a dozen items at once the sheet ended up pretty flexible and started to warp so I ended up remaking the whole thing in 6mm mdf instead. That's currently working very well but if it shows signs of degradation I'll just send off to have one laser cut in metal instead.











by noreply@blogger.com (Martin Raynsford) at 12 October 2017 08:37 PM

Hummingbird Protoype


I was inspired by the Colibri Hummingbird Automata to make this flapping wing version of my own automata. The flap isn't quite so good but the mechanism is a little simpler and it will suffice as a prototype for now.





by noreply@blogger.com (Martin Raynsford) at 12 October 2017 09:59 AM

09 October 2017

Martin Raynsford hackergotchi for Martin Raynsford

New Tool: Vacuum Former


About 2 months ago I was talking about getting some parts vacuum formed so I had a quick look on ebay to see how much vacuum formers were and found one very local that was going cheap (comparatively). It needed to be gone by Monday morning, I found it Saturday morning, and it was a big industrial beasty that would probably need a van with a tail lift to move it. A few quick emails/phone calls later and I'd booked a van, spoken to the sellers, found a friend to help and things were all set for Monday morning. I'd gone from thinking about vacuum forming parts to owning a machine in the space of a few hours.

Moving day was fun, the machine is indeed big, heavy and very industrial. The machine had been unused for a while and the previous owner had it wired directly in to the wall because high currents kept blowing fuses. It was fair to say I was nervous about what I'd just bought but worse case I could just sell it again on ebay (and not being in a rush I would probably make a profit on it with a proper auction).

I ignored the warnings of the previous owners, whacked a plug onto the loose wires, ensured I had a 13A fuse fitted in the plug and connected it directly to the wall. The machine crackled into life literally, the heating elements were getting warm and making plinky plunk noises. The heating tray slid nicely back and forth, the lift mechanism was good and it seemed to form a seal around the plastic sheets. While we were out collecting the machine some plastic sheets had arrived and I was ready to vac form something. Thankfully I had a laser cutter to hand so could quickly and easily make a mould.

It's a sad design but if I'm going to be posting photos to you lot then I might as well remind you who I am. I fiddled and faffed with multiple sheets of plastic, cursed at failed attempts to pull a mould, discolouration of overheated plastic and ultimately came up with something that vaguely looked like the mould that was under it. The plastic is clear 0.5mm PETG, if you heat it up too much it turns milky white, if you don't heat it up enough it doesn't pull down over the mould.


Success, or at least enough of a success that I couldn't return it to the seller with complaints about it not working. The machine was functional, I had questions about the effectiveness of the vacuum pump but sorting all that was just down to my skill and time so it did nothing else for a bit. It takes up a lot of space in the garage and it took a week or two to jiggle things round and find it a new home (This was also the time I decided to lay the wooden floor). 



With the vacuum pump not performing particularly well I was still hedging my bets on reselling it. I showed a few visitors and then while I was explaining my woes to my father in law he reminded me that he actually works with vacuum pumps. A quick hour climbing around under the machine he had pulled the pump apart, checked all the pipe seals and given it a thumbs up. He also noted that cleanliness is very important and any piece of grit around the plastic seals would allow air into the mould. All the lips and edges were sanded free of grime and wiped clean, the next pull would be as good as it gets and determine the fate of the machine.


A vast improvement, there's life in the machine after all. The machine was staying, the rest was all down to my ability and with vacuum forming jobs already creeping out the woodwork it wasn't going to be long before it was earning it's keep.

by noreply@blogger.com (Martin Raynsford) at 09 October 2017 09:40 PM

Spencer Owen hackergotchi for Spencer Owen

Retro Challenge 2017/10 Testing

The initial testing of the ESP8266 board with the RC2014 was pretty good, and fundamentally it worked.  However, it wasn’t quite right, and I suspected that the problem was to do with CR or LF.

The code I was using was found here; https://github.com/tzapu/WebSocketSerialMonitor (Thanks Tzapu!).  It uses web sockets, and allows an external web page to connect through to the ESP8266.  So, by going to http://tzapu.github.io/WebSocketSerialMonitor/ and connecting to ws://x.x.x.x:81/ws (where x.x.x.x is my external IP address and a firewall rule is set up to forward port 81 through to the internal address of the ESP) it will display everything the ESP receives on its Rx pin.  Well, almost everything, but not quie everything.

If, for example, I did a directory listing which was 2 full lines and a little bit more on the 3rd line, only the first 2 lines would show up.  If I’m playing Zork, sometimes it would show the whole chunk of text as it came in, other times it would miss the last line.

The code itself is fairly easy to read, although the complicated web sockets stuff is hidden away in libraries.  This is the part of the routine that reads the serial input until it detects a CR (the ‘\n’ part), where upon it then sends the line;

void serialEvent() {
  while (Serial.available()) {
    char inChar = (char)Serial.read();
    if (inChar == '\n') {
      stringComplete = true;
      return;
    } else {
      inputString += inChar;
    }
  }
}

I figured that adding a check for a LF would do the job;

if (inChar == '\n' || inChar == '\r') {

But, sadly, it didn’t.  If anything, it made it worse.  So, instead, I tried just reading a set amount of characters (10 initially) and sending them regardless of a CR or LF, but that didn’t work either.  When I got it to send every character without checking, it worked much much better, although if I sent a very large chunk of text it would miss random bits of it.

So, the problem seemed to be speed related.  The checking for CR was a nice idea by the original author, but it wasn’t something I needed, so time to strip out all the surplus code.  It went from this;

void serialEvent() {
  while (Serial.available()) {
    char inChar = (char)Serial.read();
    if (inChar == '\n') {
      stringComplete = true;
      return;
    } else {
      inputString += inChar;
    }
  }
}


void loop() {
  serialEvent();
  if (stringComplete) {
    
    String line = inputString;
       // clear the string:
    inputString = "";
    stringComplete = false;

    //line += '\n';
    webSocket.broadcastTXT(line);
    Serial.println(line);
  }
  webSocket.loop();
}

to this;

void serialEvent() {
  while (Serial.available()) {
    char inChar = (char)Serial.read();
    inputString += inChar;
  }
}

void loop(){
  serialEvent();
  webSocket.broadcastTXT(inputString);
  inputString="";
  webSocket.loop();
}

Much simpler, and it seemed to work perfectly!

All the testing up until this point was done either on my laptop or mobile.  Although they are on the same wifi network as the ESP, it’s connecting out to an external web page before coming back in, so it should be a reasonable test.  But there’s nothing like real people connecting in to really see if it works.  So, I put a shout out on Twitter, and on Saturday evening, 4 willing volunteers sat there watching me do random things on the RC2014.

Feedback was pretty good, and it all seemed to work as expected.  Thanks Thilo for this screenshot;

I messed about with simple programs in BASIC, directory listings, and the opening moves in Zork, with success.  In a moment of madness, I fired up Wordstar.  When the RC2014 is connected to a VT100 terminal, it works great by using escape codes to set where things are on the screen and what colours are used.  However, these escape codes don’t render at all well on the web sockets interface.  Thanks Dave for showing my just how bad it looked!

So, yes, I should have known that Wordstar would be pushing it a bit far.  But otherwise, I was very pleased with the performance.

The biggest problem I had, though, was that of feedback when interacting with the “audience”.  I could type short sentences in to Zork that the viewers would see and understand, even if the Zork engine couldn’t interpret it.  But, of course, there was no live feedback from the viewers.

I’m not sure what the solution to that will be, but it could be as simple as keeping Twitter open on my phone.  Alternatively, things like IRC or Slack could be used (although I don’t want viewers to have to jump through hoops to get connected to me).  Skype might be an option too, although, at the moment, I think it’s more likely I’ll set up a YouTube live stream and use the chat feature in that.

For those wondering about the set up that I’m using, it’s pretty much a stock RC2014 Pro with a Pi Serial Terminal and the ESP8266 prototype I built for this project.  The Pi Zero is connected via a HDMI > VGA adapter, and then to a 17″ monitor.  The keyboard is this Cherry keyboard from the last Retro Challenge.  Note that the key layout is sufficiently different from what I’m used to that typos aren’t too uncommon yet.

The laptop is there to program the ESP, and to monitor it’s output.

I am aiming to have a live run through on Friday, so that gives me a few days to look in to the feedback options.

by Spencer at 09 October 2017 07:51 PM

07 October 2017

Martin Raynsford hackergotchi for Martin Raynsford

Skulls and Engraving


I have recently been inspired by the work of Diego from the Engravers Dungeon (brought to my attention courtesy of the Laser Cut Stuff blog). He's been doing some amazing engraving of custom artworks, he's really managed to bring out the best of the wood using different colours but what really caught my eye are the two significantly different colours of laser cut. The large areas are engraved to create the typical 'brown' engraving where the wood grain can show through. The details however have this amazing 'black' engraving effect, he's understandably protective of his methods but it got me thinking about how it's done.


The laser cutter has 2 main modes of operation it can trace out a shape and cut it out or it can engrave an area where it moves over every 'pixel' within an image and puts a single dot onto each spot. Fancy laser cutters are able to vary the power of this spot to produce greyscale images, the Leetro controller (what I have) is only capable of doing on/off engraving. The burn mark is either full power or off, this produces the 'brown' engraving seen here.

There is technically one other option with the laser that I love and have used to great effect many times before. I use it for Line art, it's a cut operation but with a very low power that only marks the surface of the material without cutting all the way through it. This would appear to be very similar to what is happening here, large areas of seemingly 'black' engraving. The stuff I have previously done is much more for outlining objects but I thought I'd give it a try anyway.


First things first, I needed a suitable image to work with. I showed Diegos work to some of my friends and one of them told me that Vesalius made some anatomical drawings that would work well in this style. A quick search led me to some works of his that were recently digitised, 5 minutes on there and I had some suitable skulls to work with. I vector traced the first one and cut it (image above) and it kind of works. The skull was painted white, the brown areas are engraved and there is lots of line artwork that is starting to look correct. It works particularly well when the lines are close together but it fails on the big gaps, I needed some method for filling the gaps.

Normally when I want to engrave in greyscale I have to convert the image with a halftone effect, this varies the dot densities to produce a grey engraving effect (like how newspapers used to work). More dots make a darker area and a pattern like this fills the whole area so would be better for this line art. I converted the original image using a halftone plugin for paint.net, most raster editors have a method for doing something similar and GIMP is my suggestion if you're not using windows.


If you zoom in to the image above you can see the lots of little dots that make the image appear grey. It was natural to assume that if I drew around each of these dots I would get a similar half tone effect but done with 'black' engraving rather than 'brown' engraving. I imported the image into Inkscape and traced the image which left me with vector artwork for a halftone image. I set this up to be a very low power cut and gave it a whirl. (svg here)


As you can see the result is very effective, as a proof of concept goes it is definitely one method to achieve these kind of results from any laser cutter. The engravers dungeon clearly spends a lot more time waxing, oiling and finishing their artwork which accounts for most of the difference. I love their final pieces and am seriously tempted to own an original.

This isn't the end of the story though, if you look closely at the piece I created it looks very badly burned. Where the lines are close together it acts like a normal engrave cutting the whole area away and it looks a mess. There are many different methods to create halftone images so there are probably other ways to get the base image. As an Inkscape user I'm keen to keep everything in Inkscape so I followed this tutorial in order to make a halftone image using tiled clones. I have to admit it wasn't the easiest thing to do, the tool seems to max out at 250,000 clones (500 x 500) and it takes a long time to do but I persevered and created an appropriate image.


This image is full of little circles that don't overlap. My thinking was that they might be dense but at least the machine won't be cutting the same location over and over. Inkscape runs on a grid pattern so next time I would rotate the image 30 degrees before converting it so that the output is less 'griddy' (rotate the output back again before cutting). The result looks very effective from a distance but very 'digital' close up. (You can also see I keep adding embellishments with every cut). (svg here)


This is the point where I got carried away and shared my intermediary success with the laser engraving and cutting forum, received a dozen requests to show my workings and ended up writing this blog post (wordy for me I know). There are more things I want to try with this method....

1. This halftone effect would probably work well, instead of lots of dots the noodle shapes would outline well.
2. It is apparently possible to make halftone images using filter methods in Inkscape these look like they would create more suitable images for engraving.
3. The Eggbot from Evil Mad Scientist using hatch filling to colour in regions on their pen plotter, this would be another way to fill a region and worth investigating.

Finally the main reason my 'black' engraving looks horribly burnt is because I have a 100W laser cutter than doesn't offer particularly fine control at the low end. If I had an RF tube like Diego I would have better control over the beam power. The Glowforge laser cutter is also showing great potential for this kind of line artwork, sadly it looks as though they're about to announce another long delay on international shipping otherwise I would have mine already and I'd be able to try it out (2 years delayed and waiting)



by noreply@blogger.com (Martin Raynsford) at 07 October 2017 09:05 PM

Trays and bases


From my little bits of wargaming experience it appears that each of the models sits on a small base which needs decorating which can be done with little disks and there are trays to move whole units of models around at once (even if just for display). My idea was to combine those two things together and make bases and trays where the pattern continues, as though the whole unit were on a marbled floor. Not sure if this is a desirable thing, let me know.

by noreply@blogger.com (Martin Raynsford) at 07 October 2017 09:22 AM

06 October 2017

Martin Raynsford hackergotchi for Martin Raynsford

Grasshopper Costume



Eli wanted to dress as the Grashopper from James and the Giant Peach to celebrate Roald Dahl day at school this year. We put together a paper mache mask based on a balloon and cut about to achieve the desired shape. He's very slowly writing an instructable about the process but I thought I'd include it her for the meantime. We did laser cut a monocle for it, which either counts as overkill or finishing touches. He was very happy with the finished result and I got to play with my new airbrush for various paint effects.



by noreply@blogger.com (Martin Raynsford) at 06 October 2017 06:56 PM

Squad Racks


Another wargaming build, it amazes me how much variation there is in the way of trays and arrangements and models. It's no wonder there are dozens of companies already doing these things and yet people still ask me for something different. These 25mm trays have a hole in the bottom for a 2mm magnet which helps the models stay in place. 5 slots holds a single squad at a time. (svg here)






by noreply@blogger.com (Martin Raynsford) at 06 October 2017 09:09 AM

02 October 2017

Gareth Howell hackergotchi for Gareth Howell

Never underestimate the power of a fridge magnet.

Last Friday, I went to the ACE Study Day ‘Aspects of Publishing: Guide and Souvenir Books’ at the Geffrye Museum. We’re in the process of redeveloping our guidebook at work, and it was interesting to see how other organisations and museums had come to their decisions about the kinds of books they produce, and who they are for.

It was great to hear people speak openly about what had and hadn’t worked in their institutions, and how they dealt with external factors, such as placement within their shops and ticketing areas, and the ways that staff help sell them as part of a visit. It was also interesting to hear people speak honestly about the tensions between commercial and curatorial needs within the institution, and the strategies for overcoming them. The title of this post comes from a response to a question about the needs of museum shops to ensure they make money while maintaining the voice of the institution.

The range of publications was wide, and raised a lot of questions about where we might go with our guidebook, what its function might be, and who it is for:

  • Does it need to act as a guide? Is its main function to help guide people around the exhibition and interpret the pieces on display? Does it need to contain a map? Is the intention that the book is used while at the centre?

Our current guidebook has a spread for each of our galleries, with key objects to see, as well as a map, and information about our other business activities, such as Education, Venue Hire and Weddings. We were shown examples of books which offered ‘A quick look’, and ‘containing 10 trails’, which were specifically intended to guide the visitor on the day.

  • Does it need to focus on the collection and exhibits? Should the book be specifically tied to aspects of the collection and the exhibits we have in the space, or should it be used to open up wider themes?

In the case of the Space Centre, could we use impressive images from Hubble or NASA’s archive to frame themes we address in the exhibition, rather than focusing on objects we hold or display? This potentially gives the guidebook a longer life, as the exhibition changes over time.

The National Trust recently published Prejudice and Pride, which celebrates and focuses on LGBTQ Heritage across the National Trust sites.

By focusing on a theme in the context of British heritage, the book is not a guide to a visit, but rather a resource that reflects on hidden or previously untold histories as part of a wider discourse on heritage and what that means.

  • Who is it for? Should the guidebook be aimed at the reader who wants more in-depth information to supplement their experience at the centre? Should it be a visually led document that triggers memories and discussion about the visit? Is it aimed at all visitors, or targeted at a specific reader? Is it for kids?

Our current guidebook is a mix of all of the above, which over time (and with incremental changes) has become a tangle of information, voices and intention. One of the triggers for this new redevelopment has been the recognition that we need to focus the guidebook and ask who and what is it for.

  • Do we need more than one? Does it make sense to divide the guidebooks into separate smaller pieces which can appeal to different readers, uses and price-points?

We were shown great examples of institutions’ range of books, from text-heavy interpretations of the museum, to pocket-sized books selling at £5, to kids’ activity books, which were created in response to audiences needs.

A great example is the National Portrait Gallery’s 100 Portraits book, which is small (150mm x 150mm), image-focused paperback, and retails for £6.95. It sits within a range of other publications from the National Portrait Gallery and is the kind of thing that would make a great gift or souvenir.

As we approach our new guidebook, these questions will help us form our ideas and work out the best way forward. I’m hoping that eventually we will develop a range of books which enable us to tell our stories in different ways and appeal to different audiences with a credible and confident voice.

by Gareth Howell at 02 October 2017 02:52 PM

Martin Raynsford hackergotchi for Martin Raynsford

It's Alive! Frankenstein Cake


Continuing my work on the craziest cakes ever, Dawn and I recently made this Frankenstein cake for the preview night of Young Frankenstein at the Garrick Theatre. After I faffed around with various lifting mechanisms for a while I ended up buying a large linear actuator from ebay, it's probably overkill but the weight of cake really adds up after a while. I made the arms detachable which is easier for icing. The knife switch actually controls the motion, it's a double pole double throw so flipping it over changes the direction of the motion. Dawn from Dinkydoodle Designs did the hard part of covering the whole thing in cake and presented it to the cast and crew.









by noreply@blogger.com (Martin Raynsford) at 02 October 2017 10:24 AM

27 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Little wooden box


I made this little box as a bit of a distraction this week. I wanted to test some hinge designs again and although this has been done by lots of other people I haven't tried it before. The circular disk in the hinge allows the lid to rotate around a point, not in the centre of the material, and once stood upright the lid rests on the back wall of the box. This style could be used to stop it rotating all the way back on to itself. It didn't quite fulfil all the things I wanted from it but it gave me some new ideas about what to do next. (svg here)



by noreply@blogger.com (Martin Raynsford) at 27 September 2017 05:25 PM

25 September 2017

Gareth Howell hackergotchi for Gareth Howell

Back to School!

I’ve just signed up for the Museum Association’s AMA professional development scheme. I’m really excited about the programme, and looking forward to developing new directions and ideas over the three years. I’m also excited to be able to have a framework to support critical reflection and looking beyond the everyday demands and restrictions of the space I work in.

I’m currently working as Exhibition Designer at the National Space Centre. I’m not sure it’s the same for everyone who has a similar role, but it’s one I’ve found my way into, rather than having a defined career goal from the start. I started out after university making visual art and performance before getting excited by web design in the 90’s, and via a wiggly path involving digital arts projects, horror film festivals, motion capture, teaching, and performing as Britney Spears at Glastonbury, I joined the National Space Centre as a web designer in 2011. Through luck and meeting some great colleagues, the role has changed over the years, and these days I’m mainly designing spaces, interactives and graphics, as well as being involved in the Exhibition Leadership Team.

I don’t think it’s necessarily a bad thing to have had such a varied work history. The transferrable skills, approaches and ways of thinking are all valuable things to have, but I’m not sure it’s consistent, and it makes me anxious that I’m missing fundamental experience and understanding of aspects of the Museums and Visitor Centre sector.

I’m also, to be honest, not entirely sure what Exhibition Designer means! Should I be writing and proposing stories and treatments for the galleries and the visitor experience? Should I be walking round with a pencil behind my ear, or heavy rimmed glasses and a turtle neck jumper? Should I be providing detail drawings and material lists to contractors? Should I be writing interactive software, or briefing someone else to do it? Should I be researching audiences, trends and new ways to engage visitors? Instinctively, I think it’s all of these things, but I’m aware that as I look around at jobs with that title, it’s sometimes a tiny, specialised bit of that list that people are looking for, and sometimes all of it and more!

The National Space Centre opened in 2001, and in some places, you can really tell! That’s no criticism, it’s the reality of any museum or exhibition space. Knowledge develops and changes, stories gain or lose relevance, audience expectations change, and parts of the exhibition begin to look dusty and dated. We are lucky to have an exhibition team in-house who can continue to refresh and redevelop the centre, whether replacing a damaged graphic or reimagining a space to communicate an idea better, or to allow our visitors to experience it in a new way. As a team, we are developing new ways to make the exhibition more accessible, inclusive and participatory.

I’m lucky that work is giving me the time and space to work on the AMA, and to be part of a team that values the need for research and reflection. I’m looking forward to asking the tough questions about what my role is and should be, and what the National Space Centre is and can be. I’ll be posting my thoughts and questions here as I go (I’ll tag them as AMA), it would be great to hear from you!

 

by Gareth Howell at 25 September 2017 05:32 PM

22 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Coaster Jigs


They may not look like a lot but jigs like this can be pivotal to the success of a large project like the 100 coasters I made yesterday. If you're going to be doing anything 100 times it's worth spending a few minutes considering how you can make each step smoother to cut down on assembly time. Here are just a few questions you want to think about and if you answer 'Yes' to any of them you probably want to make yourself a jig. Thankfully the laser cutter is particularly good at making jigs for parts as well as the parts themselves.
  • What is the most efficient order for assembly?
  • Do parts have to be specifically aligned to each other?
  • Where does the glue have to go and are there places where the glue shouldn't go?
  • How do you remove the part from the jig once it is assembled?
These coasters break down into 2 parts of 3 layers each. The inner triangle has a middle layer that is smaller than the outer layers, this means it needs to be aligned perfectly in the centre and because it is on the reverse side of the cutting we can't just draw registration marks.


The first jig is designed for gluing the middle layer to one of the outer layers. It is a stepper tray, the smaller piece sits right at the bottom and the larger piece sits on top of it, the two parts are held in position until the glue dries. The glue is applied to the smaller part, this is because we don't want any overflow around the edge of the larger part, applying glue to the smaller side means that it is going to stay between the two pieces. It was easiest to run all these parts together in a single batch of 100, this means the glue will have dried before we try to use the part again in the second jig. 


The second jig holds all the pieces for final assembly. The outer square is built up in 3 layers again but the middle layer is thinner this time to allow it to sit in the groove around the edge of the triangle. 
The newly glued part is aligned in the middle of the jig by a corresponding 'V' shaped layer, this just squares the piece up and ensures it isn't in the way of the outer layers. Glue is again applied to the narrow bottom layer to glue spillage and the middle layer is installed as 4 separate pieces. These pieces overlap onto the triangle. The top layer is glued down to form the outer frame work and finally the top triangle is glued into place (and aligned by eye) to secure the triangle into the frame. The newly formed coaster can be poked out of the jig using the hole in the bottom. The whole process took about 3 minutes.

by noreply@blogger.com (Martin Raynsford) at 22 September 2017 01:11 PM

21 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

100 Coasters


I had a pretty busy and productive day yesterday assembling these coasters. They're now headed off into the post with the hope that they'll arrive in Edingburgh for an exhibition at the weekend. 100 coasters in a (long) day is not bad work at all.


by noreply@blogger.com (Martin Raynsford) at 21 September 2017 01:05 PM

20 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Tool Key Ring


Basingstoke Makerspace recently asked if I would be able to modify the design of the Reading Hackspace tool key ring to include their logo (a small piece that they use to demonstrate the lasers capabilities). It was a simple task but I thought I might as well cut one at the same time. The Hershey text containing the URL is perhaps a little bit small but I was impressed that the laser picked up all the details.

by noreply@blogger.com (Martin Raynsford) at 20 September 2017 11:01 PM

19 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

More Vale Runes


Once you take shiny things to a LRP event people start to realise how useful they can be, the trouble is that everybody really needs something different so they can identify it as their own. Wood dyes have been extremely useful to reproduce these sets of vale runes. Everything else is the same really but the wood was dyed before being cut so they end up looking quite different.

by noreply@blogger.com (Martin Raynsford) at 19 September 2017 01:15 PM

17 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Hidden Messages


I made these story disks for Vale, each one has an encrypted message spiralling around the disk from the inside out. The encryption is made even harder by the fact it is displayed in the vales own font, 26 runes representing the 26 letters of the alphabet.

by noreply@blogger.com (Martin Raynsford) at 17 September 2017 05:01 PM

15 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Vale Box Comission



I love how the laser cutter allows me to make the same thing but customised and ever so slightly different. This is the same vale box that I've made twice before but I tweaked it and put a different cover on the top. Each iteration gets me an easier build, takes less time to assemble and recoups some of the time investment, I'm always happy to take on more rebuilds.



by noreply@blogger.com (Martin Raynsford) at 15 September 2017 05:28 PM

14 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Stat Counter


After making the other types of counters recently I was asked if it was possible to make a small counter that tracked 5 stats at once. I gave it a good effort but it's a little bit small and fiddly to use at this scale. I may take another shot at it to see if I can make it more useable but there isn't a lot of room left in that base





by noreply@blogger.com (Martin Raynsford) at 14 September 2017 05:17 PM

13 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Quick stencils


I needed a set of stencils for painting onto fabric, thankfully I had some mylar on the shelf and I was able to create these really quickly.

by noreply@blogger.com (Martin Raynsford) at 13 September 2017 05:12 PM

11 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Leicester Guildball Markers


I've been making a range of items for the Leicester Guildball Group recently because I'm local and have a laser cutter. It's all fairly standard stuff but it's nice to see people using the things you make.



by noreply@blogger.com (Martin Raynsford) at 11 September 2017 09:44 PM

08 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Best Ever Wood Glue


I make a lot of things out of wood because it laser cuts incredibly well, it's cheaper than plastics and you can glue it together. I've tried quite a lot of glues and I really like this Weatherproof Exterior glue from Evo-Stik. I've been buying it in smaller bottles with applicators but recently discovered that Rapid Electronics sell it in 2.5 and 5L bottles, suitable for refilling all of my smaller bottles. The glue grabs within a few minutes and sets solid and clear overnight, I'd definitely recommend getting some.

by noreply@blogger.com (Martin Raynsford) at 08 September 2017 09:44 PM

07 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Exhaust Fan Upgrade


My extractor fan always sat at an awkward angle where the inlet needed to be on the wrong side and the outlet was best pointed vertically. I previously achieved this using some shelving brackets but it was always a bit wobbly. While I was laying the floor I noticed that they were bent and the whole thing was touching the floor so I upgraded to this wooden stand instead. The fan is now held firmly in place again, better than ever before. The whole thing tucks in neatly behind the new machine in the garage.


by noreply@blogger.com (Martin Raynsford) at 07 September 2017 07:48 PM

05 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

New Wooden Floor


The floor in the garage was just sheets of plywood which has served me very well over the past few years but it was starting to look a little worn. In my week off I laid a nice new wooden floor over the top of it. It was fun juggling all the stuff from the front to the back of the garage and finding it all new homes but the floor is in at least and looking good. I still have to sort all the junk that got moved up onto the shelves and hidden around the house but it's a good start.




by noreply@blogger.com (Martin Raynsford) at 05 September 2017 08:17 PM

Gareth Howell hackergotchi for Gareth Howell

BSA Scientist Top Trumps

I’ve just finished working on a set of Scientist Top Trumps for the British Science Association : Brighton and Hove Branch. They were launched on the 5 September, as part of the British Science Festival 2017, with different cards being placed in venues across the city, encouraging collectors to visit the different spaces and take part in the talks and activities there.

It’s been a really fun project to work on, and it was great to have the opportunity to work with the BSA. I really liked the diversity and range of scientists who were featured, and enjoyed reading their stories. The colours and fonts were chosen to fit the BSA branding guidelines, and I made an icon pattern for the back of the cards. The portraits were found on Wikipedia, with the background headers coming from stock, or public domain libraries.

Here are some of my favourites. If you’re out and about in Brighton, try to collect the set!

 

Henrietta Swan Leavitt CV Raman Grace Murray Hopper Percy Lavon Julian Katherine Johnson Max Planck

by Gareth Howell at 05 September 2017 06:51 PM

04 September 2017

Martin Raynsford hackergotchi for Martin Raynsford

Keeping the laser busy



I have a few relatively big cutting jobs to do over the last few weeks. They keep the laser busy while I'm free to answer emails, sort paperwork and all the other boring jobs that occur as part of life. Hopefully many of you will have noticed the not so subtle changes happening to the blog too as I try to get this sprawling monstrosity of 1200 posts into slightly better order of things. I'm not allowed to mention most of these projects yet but the posts are written and waiting for specific dates.

I have however been cutting some more Hex Terrain Toolkit which seems to be a very successful project for Ross.


by noreply@blogger.com (Martin Raynsford) at 04 September 2017 07:51 PM

31 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

More Wound Counters


These white on black counters were much simpler than the others. The actual numbers on the dial still had to be done with a paint infill but the actual symbol and lettering was engrave so they show up white enough to not need painting.

by noreply@blogger.com (Martin Raynsford) at 31 August 2017 09:52 PM

Gareth Howell hackergotchi for Gareth Howell

Eden: Journey into Space

Earlier this year, I worked with the Eden Project on their new summer holidays exhibition, Journey Into Space. The exhibition formed their summer programme, and included an Alien Encounter, Astronaut training, a Solar System Safari and a VR Theatre, alongside talks and activities.


 

The key areas we were involved in designing were the Solar System Safari, and the VR Theatre.

The Solar System Safari is a walkthrough exhibition which takes the visitor through the Solar System, starting from the Sun and returning to Earth at the end of the journey, via ten interlinked spaces. Each space in the exhibition uses elements of sculpture, lighting, audio and video to give the viewer an experiential view of the planet or Solar System object.

The process of working with the team at Eden involved collaborating (mostly remotely) to fix ideas, scope the needs of the individual rooms and to design the piece to make a coherent journey. It was important that each room gave the viewer a different experience, and that the story of returning to Earth was key to the exhibit.

Our initial process involved using Mural to throw together visual ideas and inspirations. The advantage of using Mural, especially in remote meetings was the potential to update live and add new elements as they were discussed. From this early collaboration, we were able to map out the space, and to begin to design the elements of each space.

I mapped out the space in Sketchup, which allowed us to get a real sense of the space, and to begin to work out the sizes and technical needs for the projections, as well as the set elements.

Our team at NSC Creative was responsible for creating the media elements for the exhibition, which included an animated Sun, volcanoes on Venus, a Pepper’s Ghost projection of Saturn, and a five screen animation of the Earth as seen from the ISS.

On-site install.

In early July, Kyle and me headed down to Eden to spend a week installing the media and helping to get the exhibition ready for opening.

The Solar Safari is built on the stage area of Eden, a temporary exhibit space which is used for Eden Sessions, holiday exhibits and special events. This meant that the exhibition was installed in a week, from start to finish! There was a large team working throughout the day to build, install, troubleshoot and tidy the space. The atmosphere was great, and the team was fantastic.

It was great to see the exhibit forming around us, and to be involved in such a concentrated burst of activity.

Painting the Sun Kyle in a cave Mars surface ISS in progress Backlit Milky Way Ceiling

It’s been an honour to work on such a large and fun project, and to spend time working with the team at Eden. It’s been great to see people’s reactions to the project too!

 


by Gareth Howell at 31 August 2017 02:17 PM

30 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Paint Infill Experiments




I read on the internet about a few different techniques to infill acrylic with a different colour. I've done some previous painting where I engraved the protective cover off the acrylic. I found that engraving that protective sheet can be a bit hit and miss, sometimes it engraves fine but other times it just appears to melt so I prefer to peel it off now. I tried to apply some vinyl transfer tape which engraves better, this was effective but it seems silly peeling off one sheet and applying another.

I settled on a compromise between the two. Since all the numbers and words around the outside are cut using Hershey text, instead of engraving they cut cleanly even through the protective sheet. The engrave in the middle of the item is done by first outlining the engrave with enough power to cut the sheet and then peeling the sheet off from the place that's going to be engraved. The idea is to do it in a single piece so they will be no weeding, the engrave can then be done in the gap that remains. The item can then be painted and once dry you can peel the mask off and you only need to clean up the engraved area.


by noreply@blogger.com (Martin Raynsford) at 30 August 2017 09:41 PM

29 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Wound Counters


I was asked to make some wound counters for a war gaming friend, the counters need to go up to 30 and still be a sensible size so I based them upon my Tigris Counters. I didn't want to use magnets in the middle though so I ended up gluing the parts together instead. They work well. 
I used white acrylic paint to provide high levels of contrast on the lettering and image.





by noreply@blogger.com (Martin Raynsford) at 29 August 2017 03:10 PM

24 August 2017

Gareth Howell hackergotchi for Gareth Howell

Freeze Tag

Karen Forever

by gareth at 24 August 2017 06:47 PM

23 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Tablet Weaving 2


I recreated these tablets with a different image by request.
I've also been working on some acrylic with paint infill experiments recently so expect me to post about those shortly.


by noreply@blogger.com (Martin Raynsford) at 23 August 2017 10:28 PM

20 August 2017

Iain Sharp

The “Electronics Kit” Common Emitter Amp

One project that’s been in my mind for ages is to revisit some of the circuits from my childhood Philips X40 kit. I finally got around to putting “Experiment 5 – Telephone pick-up and amplifier” in to my circuit simulator. This is the first of several audio amplifier circuits in the manual, and they all follow the same design pattern. Similar circuits are also used in other educational kits. I had tried to use this circuit design in my own electronics experiments as a kid. Mostly it didn’t work, but sometimes it did. As an adult, I was interested to understand its characteristics to help explain where it’s appropriate.

View the about in full screen.

Looking at the simulation you will notice the amplifier is non-linear (compare the shape of the top of the sine wave out to the bottom in the output of the first stage). This isn’t unexpected given that transistors have an exponential relationship between the base voltage and the collector current. The biasing on the second stage also looks bad, meaning that the output signal is clipped on the positive side. The simulation result raises several questions in my mind:

  • Why is this type of amplifier so popular in basic electronic kits?
  • Are they circumstances in which the amplifier is linear?
  • What are the characteristics of this type of amplifier anyway?

To answer these questions, let’s look at the basic building block of this amp. It’s a single transistor common emitter configuration. The biasing is from a high value resistor between the collector and the base. Wikipedia informs me that this configuration is called “collector feedback bias“. The signal is coupled in and out of the stage through capacitors.

Single Stage of Amplifier

Looking at this circuit you can guess why it’s popular in these kits: the component count is very low. Hence, it is easy for kids to build. If you have an intuitive understanding of transistors, you might also guess that resistor between the collector and the base creates negative feedback giving the circuit the ability to find a suitable operating point across a range of conditions.

As all the textbooks tell you, transistor amplifiers require that the transistor(s) are “biased” correctly to work. The aim of biasing is to set the DC conditions around the transistor so that it is in the “active zone” of operation. The active zone means that you are past the threshold for the base voltage required to start to turn the transistor on, but not yet at the base voltage where the transistor is fully turned on and saturated. The DC conditions that the biasing establishes are called the “operating point”.

As I mentioned, in this circuit the base resistor provides negative feedback which tends to stabilize the operating point. When the circuit is switched on there is no current through the transistor so the collector voltage is at the power supply voltage and the base is pulled high though the two resistors. This rising base voltage turns the transistor on and this pulls the collector voltage down (because of a voltage drop through the collector resistor) which in turn reduces the base voltage – tending to turn the transistor off and reduce the collector current. In practice, these effects will almost instantaneously reach equilibrium with the transistor in a partially on state – i.e. in its active region.

Wikipedia gives a pretty good explanation of how to calculate the operating point so I won’t repeat it. One thing to note though, for the resistor values used in this configuration, the operating point will depend on the gain (β) of the transistor so the operating point will change for different transistors. Here is a graph showing how Vc depends on the gain (β).

Theoretical Vc (Y axis) Vs Gain (X axis) for Circuit Shown Above

So, that just about wraps-up the situation for the DC bias. It works just about OK as long as you aren’t fussy and don’t expect a big output voltage swing I guess! What about the AC characteristics of this circuit? What is the gain? What about this non-linearity effect?

I checked a few standard text books, and the web, and couldn’t find a theoretical treatment for this circuit configuration so I had to come up with my own. Let’s start by assuming that the impedance of the input source through the coupling resistor is low compared to the input impedance of the amplifier. In that case the input signal becomes just a change in voltage on the base of the transistor (ΔVBE). In that case we can use the Ebers-Moll equation for the transistor to work out the impact on the collector current (and hence the collector voltage). Ebers-Moll says:

IC2/IC1 = Exp( ΔVBE / VT ) Where VT ≈ 25.3mV at room temperature

If you write IC2 = IC1 + ΔIC, and convert the collector current to the corresponding voltage you can get the solution:

ΔVC = ( 1 – Exp( ΔVBE / VT) ) . ( VCC – VC1 )

Where VCC is the power supply voltage and VC1 is the voltage at the collector at the quiescent operating point

That equation fascinates me for two reasons:

  1. Clearly, this is an exponential amplifier – which explains the non-linearity
  2. The gain depends on the collector voltage at the quiescent operating point. The graph above which shows how the operating point changes with β translates to changes in the stage gain.

Can we imagine this amp could be approximately linear? Well, as my high-school physics teacher said “everything is linear if you look at a small enough range” (cue sound of 1,000,000 mathematicians groaning). So, we know by Taylor expansion that:

Exp( x ) = 1 + x + x2/2! + x3/3! + …

So, if ΔVBE << VT we can approximate the exponential using just the first two terms above.

ΔVC ≈ – ( ΔVBE ) . ( VCC – VC1 ) / VT

In other words, for very small input signals (<< 25mV) it is kind-of, sort-of, a linear amplifier of gain ( VCC – VC1 ) / VT . Here are some handy plots from Mathics of gain Vs β, Rc and Rb.

Stage Gain (Y axis) Vs β (Top), Rc (Middle), Rb (Bottom)

Actually, the stage gain in this configuration is quite high, though very dependent on the β of the transistor. I might also remark that the output impedance is poor (limited by Rc ), though, without having done the calculation, I think the input impedance is probably OK.

So, if you want a high gain, single stage, small signal amp with very few components, and, you aren’t too worried about predictability of the gain OR linearity OR output impedance then this circuit just about does the job. This actually fits the bill for these beginner’s electronic kits pretty well. If your requirements are more stringent then better avoid this circuit and look for others. Just one thing still seems odd – why is the second stage bias set where it is on the original circuit?

For me it’s been interesting to look at how much information you can extract about this, fairly trivial, circuit and it’s certainly refreshed my understanding of transistor fundamentals. I hope you find it interesting too.

by Iain at 20 August 2017 06:43 PM

11 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Reuleaux triangle coaster


I was approached with a design for a coaster using a Reuleaux triangle in the middle. It is a shape of constant width so it is able to rotate within a square just like a circle would. I made some tweaks to the design like putting in a lip on the middle layer to stop the shape falling out. It works and is fairly functional but it's not very smooth and it squeaks as it turns, I've yet to come up with sensible solutions to those problems.


by noreply@blogger.com (Martin Raynsford) at 11 August 2017 09:28 PM

07 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Geometric Embroidery T-Rex


The T-Rex is the last of the Dinosaur range for the moment, I have the knack of drawing now and the style and also I ended up buying 36 embroidery skeins so I'm sure there will be lots more variation in the future. For now, here are the dino buddies, happily playing together.


by noreply@blogger.com (Martin Raynsford) at 07 August 2017 10:12 PM

06 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Geometric Embroidery Triceratops


Another embroidery dinosaur, this one was much quicker to draw and now that I've found an embroidery needle it was much quicker to sew (please ignore the snag on the back like I did :p). I'm pleased with these so I expect I'll be putting a set of three up in the store shortly.




by noreply@blogger.com (Martin Raynsford) at 06 August 2017 08:20 PM

05 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Geometric Embroidery Velocirapter



I think the title just about sums it up, I was looking at some of the Cotton Clara designs and I was inspired to make my own embroidery designs based upon dinosaur shapes. I think they'd make fun little kits for kids.



by noreply@blogger.com (Martin Raynsford) at 05 August 2017 07:55 PM

04 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Lasercut Sugar Cookies


In a slightly strange obsession I've developed I've started trying to cut some edible materials. I've cut gingerbread in the past and it works ok but it's a bit stinky. This was a sugar cookie recipe I tried. As you can probably see immediately there was a big crack appearing on the surface before I even started cutting. The laser seemed to go through it easily and a lot of smoke came out from underneath, a sure sign it cut all the way through, turns out it hadn't though. When I eventually broke the shape out there appears to be a seam running across the middle of the biscuit too which made it snap in half that way. A bit of a failure all round and it was still stinky and didn't taste very nice so time to move onto the next recipe.



by noreply@blogger.com (Martin Raynsford) at 04 August 2017 01:05 PM

02 August 2017

Martin Raynsford hackergotchi for Martin Raynsford

Yet More Runes


As I mentioned a lot of games use rune systems, upon seeing my previous runes I was asked to make a set for another game, I wanted to make these more ornate than previous runes so I engraved a pattern onto the base tile and then outlined the rune on top of that (The inside of the rune isn't engraved with the pattern)


by noreply@blogger.com (Martin Raynsford) at 02 August 2017 09:13 PM

01 August 2017

Spencer Owen hackergotchi for Spencer Owen

Decoding ROM labels

Back in the earliest days of the RC2014, it came with a pre-programmed 64k ROM, with Microsoft BASIC on it in the first 8k, and it would work with 32k of RAM and a 68B50 ACIA.  One set up, one ROM, life was simple!

As time has gone on, and more options have become available, other ROM images, such as Microsoft BASIC for 56k RAM, or CP/M Monitor have been introduced.

Future possibilities, such as other UARTs, different CPUs or other variations will inevitably lead to more ROM images being needed.  So, in order to keep track of what is programmed where, ROMs are now being shipped out with a label on them.

Every ROM now has an 8 digit code on it.  Each digit, from left to right, refers to an 8k bank from 0x0000 to 0xD000.  This bank can be selected with the A13, A14, A15 jumpers;

Address A15 A14 A13 ROM Label
0000 0 0 0  Xooooooo
2000 0 0 1  oXoooooo
4000 0 1 0  ooXooooo
6000 0 1 1  oooXoooo
8000 1 0 0  ooooXooo
A000 1 0 1  oooooXoo
C000 1 1 0  ooooooXo
E000 1 1 1  oooooooX

 

The value of the digit represents the ROM image that sits in that particular 8k bank.  Currently, it will be one of the following;

0 – Empty bank, available for user to program

R – Microsoft BASIC, for 32k RAM, 68B50 ACIA, with origin 0x0000

K – Microsoft BASIC, for 56k RAM, 68B50 ACIA, with origin 0x0000

1 – CP/M Monitor, for pageable ROM, 64k RAM, 68B50 ACIA, CF Module at 0x10, with origin at 0x0000

2 – Microsoft BASIC, for 32k RAM, SIO/2, with origin 0x0000

4 – Microsoft BASIC, for 56k RAM, SIO/2, with origin 0x0000

5 – Microsoft BASIC, for CP/M installation,64k RAM, 68B50 ACIA, CF Module at 0x10, with origin at 0x2000

6 – CP/M Monitor, for pageable ROM, 64k RAM, SIO/2, CF Module at 0x10, with origin at 0x0000

 

As more ROM images are added, this list will be updated.

 

Standard factory ROM images can be downloaded from Github https://github.com/RC2014Z80/RC2014/tree/master/ROMs/Factory

by Spencer at 01 August 2017 08:42 AM

31 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Cake Baking


We baked cakes, of course letting Hazel chose something from the Halloween cookbook probably wasn't the best idea but a good time was had by all. They were yummy too.




by noreply@blogger.com (Martin Raynsford) at 31 July 2017 03:22 PM

30 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Currency System


I was asked to envisage a currency system for a futuristic LARP game. I came up with these denominational coins, each value has a different shape and colour to signify it's different value. The number is engraved on the reverse so it adds depth to the token. There are fine details drawn with line art on the top to replicate the intaglio printing found on banknotes. Finally each curved section was made with the same curve, this means each coin can tessellate on it's own sheet to optimise cutting but they also tessellate with the other coins to form more interesting patterns.

I tried a couple of different styles with the plastic backing sheet but ultimately I think they work best with the whole thing peeled off before cutting the details.





by noreply@blogger.com (Martin Raynsford) at 30 July 2017 05:21 PM

29 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Electric Drill Cake


Dawn recently made this stunning electric drill cake and casually mentioned that it would have been cool if the drill bit was rotating. I jumped straight on it and made this little unit which could rotate a plastic tube around a metal shaft. The threaded rod can support the cake and the drill bit can be applied to the tube. The plastic tube comes off the threaded rod to allow it to be decorated easily.
Sadly I don't think there are any videos of it rotating but I did take a video of the motor in action.




by noreply@blogger.com (Martin Raynsford) at 29 July 2017 05:22 PM

28 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Second Number Display


Vale LRP has two distinct alliances, two sides of the war battling against each other. This means I often get to make the same thing for both sides but they should be done with different styles. This number display was done in the style of my church windows. The LEDs shine through a piece of thin flexible wood veneer so when they are off the whole thing just looks like a piece of wood. This display was fixed into the infernal machine along with many other parts I've made for it, 5 Point Iris, Planetary Gears, Knife Switches and Filling Mechanism

by noreply@blogger.com (Martin Raynsford) at 28 July 2017 05:58 PM

27 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Curved Lid Box


The curved lid that I vacuum glued veneer over was used to make this box. It was made quickly to look like a wooden chest but it was never intended to be functional. The side panel is made from a single section so that it always stays open and the lid can't close. The whole thing was skinned in a wood veneer to make it the same colour as the lid and some metallic card was wrapped around the box to look like bindings. Inside the box is a scroll of paper that is used to display 'mystical' numbers. I will write about that project as soon as I get it back but for now I'm missing photos of the hardware.

by noreply@blogger.com (Martin Raynsford) at 27 July 2017 08:50 AM

25 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Wargaming Counter Bases


Using the same magnetic counter technique I had on the Tigris counters I made up these bases which track the stats of the character sat on it. It's all a little bit small and fiddly but it was functional. I think it would need another iteration to actually be useful.


by noreply@blogger.com (Martin Raynsford) at 25 July 2017 09:34 PM

24 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Zaros Godsword


Another collaboration with Eldritch, this is the Zaros Godsword from Runescape. Using this image as a reference I was able to draw up and cut the sword, although I quickly realised the sword in the image isn't straight so I had to take a few liberties with the final piece. It's built like a normal LRP weapon with a carbon fibre rod core and multiple layers of plastazote LD45 foam. The finished piece was glued, latexed and coloured by Eldritch.



It's a bit hard to see on the white foam but the blade was actually engraved with a design.



by noreply@blogger.com (Martin Raynsford) at 24 July 2017 04:54 PM

23 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Gluing curved surfaces


I wanted to make a curve lid for a classic pirate style treasure chest, I didn't really consider it before making and before I knew it I had stacked dozens of pieces of 6mm ply into a pile to give me the right shape. It doesn't leave a very nice edge though so I decided to skin it with a piece of flexible wood veneer. I started by gluing the veneer along one edge of the curve but I didn't have enough clamps to hold it in place across the whole surface. The solution is to vacuum seal the whole thing in a ziplock bag. It's a very simple process where I sucked the air out of the back once the curve had been glued and this provided suitable pressure to hold the veneer in place until the glue had dried. I use evo stick wood glue with resin that grips the material in about 5 minutes. After that point you can remove the item from the bag and it will dry properly over the next 24 hours. I didn't take any specific pictures of the lid but I'll have some images of the box soon. 





by noreply@blogger.com (Martin Raynsford) at 23 July 2017 05:11 PM

Iain Sharp

A nice 3rd party sequencer for the LushOne

Rakits Baby 8

I often get asked “is there a sequencer for the LushOne” and the answer, currently, is “no, because I never got around to designing one”. Of course, the LushOne has slightly non-standard voltages (at least relative to Eurorack norms) which means that a lot of off-the-shelf sequencers need some external adaptors to nicely connect.

I was delighted recently when a customer who had asked about a sequencer sent me a link to the Baby 8 available from Rakits (also in the UK). This little kit is about as close to an ideal beginner’s sequencer for the LushOne as you can get. The output voltages (0V-5V) are compatible with LushOne gate and CV inputs. The power supply voltage is the same as the LushOne and the design is very similar to the “all on the PCB” approach in the LushOne. The only things that are different are the board size and the connectors.

For the connectors, I added a mezzanine board on the side (see photo) to make the outputs accessible with 2mm banana plugs.  In my installation, it doesn’t need an external ground connector because it shares the power supply ground with the rest of the system.

It’s a straight-forward kit to build – all based on through-hole components. It uses the classic 4017 sequencer concept, but despite this simplicity it has some nice touches – variable gate pulse width and a gate skip feature on each step. All in all, a nice addition to any LushOne system.

by Iain at 23 July 2017 03:36 PM

22 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Welsh Masters Item


I made another item for the Welsh Masters this year, this is their logo cut from 2mm mdf, there was another layer which went on top and brought out the details of the face but I've misplaced the photo.

by noreply@blogger.com (Martin Raynsford) at 22 July 2017 05:13 PM

21 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Nespresso Pod Holder


While not completely my own build, a friend bought a wall mounted nespresso pod holder and was worried about the pods scratching the wall. I simply cut a sheet of polypropylene to go behind it which is lightweight, cheap and should prevent all scratching. 




by noreply@blogger.com (Martin Raynsford) at 21 July 2017 05:52 PM

20 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Character Shrine


I found a picture of my goblin character, that I engraved as a test piece, in the pile of scrap wood I was burning on the camp fire. I put it up in the tent and it became a mini shrine, in a self indulgent moment I decided to elaborate on the joke and made this whole mini shrine devoted to the character. It hasn't received any gifts yet but it was a fun little build.


by noreply@blogger.com (Martin Raynsford) at 20 July 2017 05:41 PM

19 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

My Vale Runes



I ordered a large jailers key ring to hold my own set of runes and when it arrived I quickly realised that the hole wasn't large enough. This was a good excuse to cut my own set of runes from real wood instead of ply, this is 2mm oak. by converting the runes to a trapezium shape I was also able to achieve tessellation for a very efficient use of material. 


by noreply@blogger.com (Martin Raynsford) at 19 July 2017 02:55 PM

18 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Vale Runes


Like most LRP games Vale has a rune system, each rune forms part of an alphabet and also has an inverse rune. I created a set of runes which include the description but also have the inverse description on the rear. These runes are used to help focus the rituals for the game and invoking the right combination of runes is the difference between success and fail for a ritual. I put a simple string hole in these with the intention that whoever gets them can tie the ones they're currently using to their own kit.



by noreply@blogger.com (Martin Raynsford) at 18 July 2017 10:15 PM

17 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Door strip



The strip between the wooden floor in the lounge and the tiled floor in the kitchen died, largely through old age and bad installation from the previous owners. When I tried to replace it I realised the problem of finding exactly the right profile for the gap. The closest thing I found took 3 days to arrive, cost a fortune and was totally wrong when it finally arrived. 
Stacking up a zillion pieces of 6mm laser ply is never fun but I actually whizzed through it in an hour because I squared them up against an angled piece of aluminium I had lying around. The whole thing was skinned with flexible 0.8mm Birch ply. In one evening I have exactly the right piece required to span the gap, nearly 2 months later it's holding up really well (a little grubby because I forgot to varnish it). I just need to lift it again now and finish it off properly.



by noreply@blogger.com (Martin Raynsford) at 17 July 2017 03:56 PM

16 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

40th Anniversary Cake Topper


My parents had their 40th wedding anniversary and my sister asked me to make a cake topper for the cake she was making. 


by noreply@blogger.com (Martin Raynsford) at 16 July 2017 05:39 PM

15 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Wargaming bases


When I'm cutting things like the caverna building trays I have a lot of gaps left over which I could easily fit something small into. My wargaming friends suggested I create some bases for their models so I threw together a few different designs for them to try. There are planks, deck plates, cobbles and gratings I just need to get someone to paint them up now. (svg here)






by noreply@blogger.com (Martin Raynsford) at 15 July 2017 05:54 PM

14 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

6mm Animals



At the Newcastle maker faire this year I spoke to someone who was producing wooden shapes from 6mm mdf using a CNC router. The process was relatively slow, dusty and required a tiny end mill to get into all the gaps. I ran these shapes through the laser cutter to get a rough time estimate for him and he now owns a laser cutter. 


by noreply@blogger.com (Martin Raynsford) at 14 July 2017 05:31 PM

13 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Raspberry Pi Case


I showed a few revisions of my raspberry Pi case previously. The final design was based upon this two part flex box so that the case can be made from just two parts and assembled without any fixings. Ventilation holes were put in the top and the USB, network and SD card are all accessible. The lower bend radius is a little bit tight so you'll need to be careful if you put one together but once it is assembled it's actually very sturdy. (svg here)




  

by noreply@blogger.com (Martin Raynsford) at 13 July 2017 05:48 PM

12 July 2017

Martin Raynsford hackergotchi for Martin Raynsford

Pyramid Display Case


This display case was a prop for a LRP event, the panels were made from clear perspex and engraved with various runes so that they would light up when the glass was edge lit. The base also has all the runes engraved onto it. There was some magic item to be placed inside the case so the sides all needed to fold down flat, this was achieved by threading some leather thong along the bottom edge of each panel. Hazel is included for scale :)







by noreply@blogger.com (Martin Raynsford) at 12 July 2017 05:39 PM