Planet Nottinghack

25 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Graham of Thrones

By request I was asked to etch an A4 sized stark wolf with a 'Graham of Thrones' caption. I used my prior artwork which is pretty to the picture sent to me which sped things up a lot. Having a nice clean line drawing allowed me to quickly raster it, to get a version without overlapping tufts and then re vectorise it (the updated 'trace bitmap' in Inkscape is incredible). The image was first engraved but it didn't pop enough for my liking so I put it back in (I hadn't moved the surrounding frame) and outlined the engraving as well. I took the decision to not etch the teeth and to only outline them which I think makes them stand out a bit from the picture. Anyway customer is happy and so am I.

by (Martin Raynsford) at 25 May 2015 10:26 PM

Dominic Morrow hackergotchi for Dominic Morrow

exploratorium, san francisco

I first heard about the Exploratorium from Tim Hunkin who has been one of the many artists in residence there. Continue reading

by chickengrylls at 25 May 2015 06:34 AM

23 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Relief Photo Frame Pair

I've been wanting to use this landscape depth technique thing for quite some time now, I have a monthly project in progress right now that uses it but while I was doing that I thought it would be pretty cool to make this pair of frames with the positive and negative images in them.

The perspex is often labelled as Glass Green which gives a slightly false impression. The backing sheet is green and it gives the whole thing a lovely green tint. In reality this is the clearest perspex sheet I've ever seen and all the green tint goes away when the backing is removed. It's really good though if you want a Glass like material. I got it from Kitronik (again)

by (Martin Raynsford) at 23 May 2015 09:36 PM

22 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Lego Mad Max - Fury Road

I must confess that I got a little bit distracted and carried away when Eli asked me to make him a Lego car yesterday. In case you haven't seen Fury Road I recommend you go and see it on the big screen it's weird, cool and it'll lose a lot of impact on the small screen. I fiddled and faffed with a few Lego pieces and was reminded of the film, from there I ended up making 6 vehicles based upon the ones in the film.

It gets a little bit image heavy from here on down so to save my regular blog readers I'm hiding it below the cut
Read more »

by (Martin Raynsford) at 22 May 2015 07:44 PM

Oak Board Game

A ye olde board game board for a game called Gluckhaus, this was cut on request for a LRP game.
The material is an oak veneered plywood that is now available from Kitronik, it worked really well for this. There are a few knots and lumps and bumps that are a bit tougher to get through but as I'm only going to be making one of these that's fine. 

by (Martin Raynsford) at 22 May 2015 10:44 AM

21 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Rubber stamp

Another simple rubber stamp, the more I do the more I learn about what not to do with these things. I should probably write something useful about how to do stamps. As much as I like having a full square background it's probably time to concede that the excess rubber should be cut as close to the stamp as possible.

by (Martin Raynsford) at 21 May 2015 10:34 AM

20 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Line Art - Varying Densities

The last of my line art experiments from last week. For this one I varied the densities of the lines radiating from the centre. The effect is much more significant than I imagined. Again I failed to cover the centre of the pattern so it burnt a hole in the middle. Maybe a sun circle in the middle of this patter. No I just need to find time to write the instructable for it.

by (Martin Raynsford) at 20 May 2015 03:18 PM

19 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Line Art - Names

This one uses the same process as the others but I tried to vary the etching pattern. There are a series of wavy lines which produce an interesting pattern around the shape. The mistake I made on this one (and the next one:) was not covering the centre of the pattern. The very middle of the etch was cut about 100 times during the process which obviously added up and put a hole through the middle of the design. "Eli + Hazel" would be been a better choice with the "+" over the centre of the pattern.

by (Martin Raynsford) at 19 May 2015 03:16 PM

Line Art - Heart in Heart

Another attempt at some fancy line art. This time I left the ends of the lines on which gives a much more defined outline to the heart shape and is also much faster to prepare.

by (Martin Raynsford) at 19 May 2015 07:12 AM

17 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Line Art - Bird in Tree

While I was busy last week I had some ideas to make something pretty for Kim. She likes birds and I wanted to try more of this line art style so I drew this Bird in a tree for her. I do intend to write an instructable about this but for now I've just attached the svg (svg here)

by (Martin Raynsford) at 17 May 2015 09:58 PM

16 May 2015

Martin Raynsford hackergotchi for Martin Raynsford


I wanted to make a little Baymax to go into Eli's birthday party invites. This is cut from 0.8mm white polypropylene. The details were coloured in with a black fine liner pen. (svg here)

by (Martin Raynsford) at 16 May 2015 10:44 PM

15 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Medium sized Empire map

By request I made a medium sized Empire Map, it's pretty much the same deal as the big one but with a few tweaks. This map is intended to be taken too and from the events so it's a bit smaller at 1000mm x 900mm. It has some extra Otkodov regions at the top and also the barrens just to the right hand side. The regions are one of three different heights instead of four different heights. The main difference is that each region is removable, this was achieved by placing two pegs under each region. The regions line up and with the pegs and sit in the right places on the board. Finally I added a little celtic flourish in each corner, you might recognise these as the Celtic knot dice. It turns out that having the six basic sides of the dice allows me to quickly and easily construct flourishes for decoration.


by (Martin Raynsford) at 15 May 2015 10:06 PM

12 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Clarkcade Gaming Cabinets.

One of my 12 projects this year was/is going to be a retro gaming cabinet. While I was at the UK Maker Faire I met Simon and I saw his awesome Clarkcade cabinets and in particular 'the fighter' which is exactly what I envisaged for my cabinet. These machines are top notch quality have all the right features and finishing touches, so I was keen to get some hints and tips. After a short discussion it turned out that Simon was keen to try getting a some parts laser cut which was very convenient, now just two weeks later I've cut my first cabinet for him and there will hopefully be many more on the horizon as we try to figure out the best way to laser these machines (such as yesterdays hidden joints). My cabinet will still be put off till slightly later in the year but what a head start I'll have when I finally get round to it.

by (Martin Raynsford) at 12 May 2015 07:19 PM

11 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Hidden Finger Joints

The weeks just fly by and it's weird because I was busy making things last week. I made a quick prototype for a hidden finger joint. The item in question is intended to be made from 12mm mdf which is something I can't cut on my 80W laser so the next best thing is to cut it in 2 pieces and stick them together. If the inner layer is hidden away though you can add these kinds of fingers to make the assembly really easy.

by (Martin Raynsford) at 11 May 2015 09:20 PM

04 May 2015

Steve Barnett hackergotchi for Steve Barnett

CNC cut control horns

I was at a loose end during today’s bank holiday so I decided to do a mini-project (with bonus recycling features) and make a set of control horns for my radio controlled SpeedTwin ST-2.

Control horns in DraftSight

After deciding on a sensible size for the control horns I drew them up in DraftSight. These ended up being 25mm tall and 12.5mm wide at the base. I designed them on a sprue so that when I come to etch the remaining copper off they don’t get lost in the etching tank. The horns are shaped so that the holes for the linkage can lie on the hinge line with plenty of material around them for strength.

The DraftSight file for the parts can be found on GitHub in my rc-parts repository, which also contains drawings of various bits of radio control hardware that I’ve designed parts around. Please feel free to use any of it or to contribute drawings of parts.

The victim

The PCB material I used comes from a nice FR4 board onto which was otherwise unusable due to a design mistake. The board was intended to be used as a 2 player version of Charlie’s ‘Minigun’ miniature SuperGun project. Unfortunately after etching I noticed I had messed up the pinout of the JAMMA connector when transcribing the design from Eagle to KiCad. Rather than throwing it away this project is allowing me to reuse the material for something useful. My 2 player ‘MiniGun’ will eventually get finished and written up too.


As a quick aside, the SpeedTwin has made some progress since I last posted about it. The fuselage is nearly finished, except for sanding the canopy to shape and some more work on shaping the nose cone. The wing is also coming along, with the top half of the engine nacelles planked and mostly sanded to shape. The remaining work on the wing is to install the tips and build the bottom half of the nacelles, which will be removable for access to the landing gear.

Once the control horn design was ready I used CamBam to convert it to G-Code. Unfortunately some manual editing was required on the output to get Grbl to accept it happily. The main problem was a G17 code, intended to signal that arcs should occur on the XY plane, which caused Grbl to error after any subsequent G3 (arc) code. This setting was default anyway so the line was removed with no adverse effects. I also tend to remove comments from any code that is passed to Grbl – the parser can choke on lines over 50 characters so comments at the end of lines are best removed. If I find an open source CAM program that will provide Grbl compatible G-Code out of the box I will probably switch to it, I just need to put in the time to find one. :)

Cutting the parts

This is the first time using my eShapeOko since I rebuilt the controller so I had to spend some time setting up again. Once I’d calculated the appropriate steps/mm settings for each axis everything went fairly smoothly and after a few ‘air cut’ test runs I cut the parts. Since this part is all made in one cut I simplified things slightly by removing all of the Z axis movement from the program. I manually plunged the bit into the work from GrblController and then set the program going.

I decided not to drill the holes on the CNC to save setup time and because I don’t have a suitable drill bit that fits my eShapeOko’s rotary tool. They will be quick and easy to drill accurately on the drill press at NottingHack at a later date.

Mostly finished parts

All that remains is to etch the remaining copper off (and sadly lose the current futuristic look), drill the holes and cut off the sprue.

by moop at 04 May 2015 07:35 PM

02 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

More Leather work

More Leather work for Marcus. I was trying to align the etch to the middle of the leather that he sent me but it didn't really work. Clearly I should have used the laser to cut out the leather as well.

by (Martin Raynsford) at 02 May 2015 10:58 PM

01 May 2015

Martin Raynsford hackergotchi for Martin Raynsford

Custom Useless Machine

The new useless machines are a lot easier to assemble, this means I'm now happy to assemble them myself and sell them as finished units. This also means I'm happy to customise the machines by request. This one was coloured red before assembly and then had a name engraved on the lid.

by (Martin Raynsford) at 01 May 2015 06:59 PM

30 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Project #5: Smart Useless Machine

I thought I would close out this month with another new product and finishing one of my monthly projects. This is the 3rd and final kit that I was calling Project #5: a complete revamp of my useless machines.

This kit is a smart useless machine, there is an arduino inside the box which allows you to program in different behaviours based upon how many times you flick the switch (or anything else you can dream of). Currently the box gets miffed if you turn it on too many times. Full sample code is provided and being based around an arduino there are dozens of amazing libraries already written for all sorts of functions. There is a small power circuit which allows the arduino to turn it's own power on and off, the only power consumed in the off state is the leakage current of the transistor. In testing the circuit ran for a whole week (2-3 tests a day).

Here are just a few ideas of things you could add:
  • Add some character to your box, with a real time clock chip make it come out slowly after midnight or once every hour.
  • Add some neopixels to make the inside of the box glow.
  • Add a second motor to make it wave the flag of surrender or run away when it gets annoyed.

by (Martin Raynsford) at 30 April 2015 10:17 PM

29 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Celtic Knot Dice

These amazing Celtic Knot Dice appeared on my Facebook feed today. I was very impressed, I rushed off to join in the kickstarter and I got there just in time with 39 hours to go.

I also didn't want to wait for my set of dice to arrive so I set about making my own. So now 3 hours later (and as of writing there is still 36 hours to go and the project is successfully funded). I present to you a DIY set of Celtic Knot Dice so you can try it for yourself before you join the kickstarter, just don't take too long about it.

My set was 18 laser cut cubes to make a nice wooden version, but I also made a paper craft version and shared it on instructables too.


by (Martin Raynsford) at 29 April 2015 03:32 PM

28 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

UK Maker Faire 2015

The weekend happened and so did my first Maker Faire of the year. The UK Maker Faire 2015, held at the Newcastle Centre for Life. With nearly 120 makers it's one of the biggest of the year but it somehow felt smaller than last years. The busy/quiet waves we experienced in the back room allowed us to have decent chats with public and other makers and there are a few new collaborations in the pipeline.

So it looks like I didn't take a decent photo of the Ping Pong Ball cannon, but I do have one of the test videos. It was a very simple design, a large air extractor was used to blow balls up the barrel, venturi effect ensured that balls were sucked in at the bottom of the barrel. The hopper was just a long line of balls ensuring that the cannon was fed quickly and efficiently.

We did a quick test on Friday, letting off 65 balls in 10 seconds and racking up a high score. The other entrant managed to get off 3 balls in the 30 second time period and scored nearly as highly as we did. After further enquiry it turns out the targets had variable scores between 1 and 10,000 (someone needs to learn about game balancing). For our second attempt on Sunday morning we let off 200 shots at a 6000 point target, we obliterated the target but only 4 registered and we were beaten later that day by a man wielding a nerf gun. (ie nothing laser cut). It's fairly disappointing to spend time and effort on something else's thing that flops so significantly, if I had known it would have been a random number generator game I would have spent my time on better things.

by (Martin Raynsford) at 28 April 2015 06:36 PM

24 April 2015

Matt Little hackergotchi for Matt Little

Datalogger Overview

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We have been working with Wind Empowerment to specify the features of an open-source data logger unit for members of Wind Empowerment to use with grid-connected and stand-alone small wind turbine installations.

After discussion at a week long hack camp in Toulouse, France the following data logger system overview was suggested.

We are working, along with other members of Wind Empowerment, to produce open-source designs for each section of the overview diagram.


by (Matthew Little) at 24 April 2015 05:03 PM

23 April 2015

Matt Little hackergotchi for Matt Little

RPM sensor

Monitoring the rotational speed of the wind turbine blades can help with power performance measurements.

This post shows various techniques to measure the rotational speed of a 'wild AC' output small wind turbine. In this system, the wild AC is rectified into DC and either delivered to a battery or to a grid-connected inverter.

The wild AC output of the turbine can be used to give us the rotational speed.

The AC waveform can be converted into a digital signal by a circuit such as this, from Noam Dotan of Comet Me:

No image

This circuit includes opto-isolation, which means the data logging system is protected from any over-voltage.

The fuse protects from any short circuit and only needs to be a low value, 50-100mA.

The zener diode limits to voltage across the LED of the opto-isolator.

The output will be a digital on/off signal for every time the magnet passes the coil. As mentioned, the number of magnets can be used to calculate the actual RPM of the rotor.

The LM7805 is a voltage regulator to give a constant voltage - the power supply of the data logger can be used here instead.

by (Matthew Little) at 23 April 2015 08:31 PM

21 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

#MFUKLC: Final Hopper

I concede the last hopper was too complicated, annoying because I'm seriously out of time to get everything done. I redesigned the hopper to be 6 very long tubes, skinned in paper again to save material. This one holds about 400 ping pong balls rather than the desired 500 balls but in testing I managed to get all my 150 balls out of the hopper in just 10 seconds, well on target for emptying all 400 in the 30 seconds of shooting time allowed.

by (Martin Raynsford) at 21 April 2015 09:40 PM

19 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Assembly Jig

Now that I'm making assembled versions of the useless machine and no soldering versions (where I do the soldering for you). I find myself trying to solder up 10 pcbs at once so I whipped up this quick little jig that will hold 20 units at once allowing me to solder them quickly and easily.

by (Martin Raynsford) at 19 April 2015 08:50 AM

17 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

#MFUKLC: Super Massive Hopper Skinned


I managed to get the skin on the hopper last night. 32 individual sections allow the balls to move freely into the cannon, simply rotate the wheel and drop the next stack into the barrel. It's interesting in theory but it's taking way too long to build so the stacks are only half as tall as they should be. 2 of the stacks were warped, I couldn't figure out why so I just cut them out.

by (Martin Raynsford) at 17 April 2015 01:23 PM

16 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Triple cut paper

While trying to build the skin for the inside of my hopper I needed to cut a lot of paper to the right size. I perforated the sheets to make them fold and fit the hopper perfectly but they were taking 5 minutes a time to cut, 5x 32 makes for a long and tedious evening. I decided to try and cut multiple layers at once. It's been a very long time since I last tried this. Previously I tried it with my HPC 3020 which made a real mess of it, the Just Add Sharks lasers have better air assist and better extraction so I was optimistic. 

I was able to cut through 3 sheets at once, but it definitely had some issues. The top layers of paper were actually blown around by the powerful air assist. This could be easily remedied with appropriately placed magnets. The bigger issue is that as you get to the bottoms layers there is increased smoke staining. So this method is really just quick and dirty and sometimes that's all you really want but if you're trying to make anything important you should always be aiming to cut 1 single layer in 1 single pass.

by (Martin Raynsford) at 16 April 2015 10:47 PM

#MFUKLC: Super Massive Hopper

I need a massive hopper to hold all the ping pong balls I intend to fire as part of the MFUKLC. I'm trying to maximize the material still so I've built up this frame work to hold 500+ balls. It's been made from 2mm mdf. I can use the extra 1mm of material in paper so I can skin the inside of the hopper to stop the balls from falling through the gaps.

by (Martin Raynsford) at 16 April 2015 10:32 PM

14 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Project #5: Useless Machine 2.0 x2

With the new box design I was able to revisit the double useless machine, this was always a bit temperamental and so was taken out of the shop. This version solves all of the previous issues, it uses the same geared motors and the same brackets as the single machine rather than modified servos (which were the cause of previous issues). The box is the same glueless design so it's really fast to put together and although I haven't been able to squeeze a PCB into here yet but the electronics have been improved. The little switch on the side turns the machine of once both arms are back inside the box.

by (Martin Raynsford) at 14 April 2015 10:07 PM

13 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Project #5: Useless Machine 2.0

My useless machine design has had a complete overhaul and this is now my best product to date. The new design features a PCB for the electronics which makes it quick and easy to solder, The box is a completely glueless construction and clips together in just 2 minutes, there are just 3 screws holding the components together. Back EMF braking stops the motor dead so the machine doesn't just use the limit switch as a mechanical end stop (unlike other designs)

The new kits are available from my web store in 3 different flavours, "Soldering Required", "No Soldering" and "Assembled". There are also 2 more variations due out before the end of the week.

This new design has some clever features. The lid hinge is now made up using the sides of the box, the flap rests on top of the sides which prevents it from falling back into the box. The motor mount is a single piece which stretches between the top and the bottom of the box. The PCB can accommodate screw terminal connectors for the motor and battery which allows me to sell a 'No Soldering' version of the box. The skin clicks into place using the clips on the bottom of the sides, the tension in the living hinge sections keeps the skin in the hooks.

Project #4 still ticks over in the background but this project has actually been in development for a few months now and needs to be released in time for the UK Maker Faire in just 2 weeks time. The kits are cut and the stock is ready to go.

by (Martin Raynsford) at 13 April 2015 12:07 AM

08 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Clamp Hanger

I love laser cutters! I've done a few repetitive projects recently, like catan, and I've grabbed a handful of clamps, brought them into the lounge and done all the tedious gluing in front of the TV. The clamps normally live on the cross bar in the garage and as I was sticking them all back on again for the umpteenth time I realised I needed a hanger. Something to hang from the cross bar that all the clamps stick to, this way when I want all the clamps somewhere else I can just take the hanger and move them all at once (svg here)

by (Martin Raynsford) at 08 April 2015 09:15 PM

07 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

More movement trays

I just completed another batch of movement trays, apparently a larger lip is required to make them work properly so these at 2mm and 4mm layers (just in case anyone was remaking them).

by (Martin Raynsford) at 07 April 2015 03:05 PM

Matt Little hackergotchi for Matt Little

LM2574 Voltage Regulator Kit

No image

This is a simple voltage regulator kit based upon the LM2574 step-down regulator IC.

If you have every needed to efficiently step-down a voltage from anything up to 60V DC to 5V regulated then this kit is for you. It can supply up to 500mA of current and is a DC-DC switching circuit which efficiently steps-down the voltage.

It is available from just £7 (including delivery within the UK).


by (Matthew Little) at 07 April 2015 10:30 AM

Battery Monitor Units

No image

We have recently been working with Product Health to develop some hardware for monitoring battery banks in off-grid systems.

Product Health are working on remote monitoring of systems to ensure they are working and pre-empt any maintenance or repair which might be required.

The product specification was to build a low-cost, reprogrammable and accurate unit to measure current and voltage at a reasonably high sample rate and send that data, when called, via a communications interface.


by (Matthew Little) at 07 April 2015 09:51 AM

06 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Project #4, All in the box

I managed to fit all of the laser cutter components back into the box again. Getting the cover on was a significant step towards seeing where everything will fit. Sure there are cables strewn all over the place but they can be routed round as required, finding the space for each of the boxes was the important part. The high voltage PSU and the Stepper motor PSU all tuck into the gap on the right hand side of the case. The stepper motor drivers and control board can fit along the front edge of the machine. Now I just need to drill more mounting holes and shorten a whole bunch of wires.


I have totally managed to remove the lower half of the machine and the only thing I've lost is the ability to engrave boxes (or at least I have to engrave boxes slightly differently)

by (Martin Raynsford) at 06 April 2015 11:59 PM

More Catan Development

Development work on my Catan set continues. This is another complete set done with painted tiles instead of real woods. I'm trying to balance materials costs vs time costs while trying to minimise both but it's not going so well.

  • I'm happy with the artwork now but I'm not sure about the painted tiles, it's a bit of a false economy because the amount I save on real woods I lose on painting and drying time. 
  • This set uses 1 magnet per side which means the tile only match up in 3/6 rotations. This is fine for the resource tiles where the orientation doesn't matter but this causes an issue with the port tiles. I suspect I'll be switching back to border tiles for the next test.
  • I tried to bring the tile thickness down, the base is made of 2mm mdf, the same thickness as the magnets but it's hard making sure each magnet is perfectly flat. I'll be going back to 2.7mm poplar for the base.
  • The coloured resource section is 1.5mm (making the while tile 3.5mm thick). There is 0.7mm between the tile border (0.8mm ply) height and the tile height, this isn't really tall enough to keep the roads in the right places. I also don't like doing the borders in 2 segments so next time there will be a whole layer of 0.8mm across the top and 1.5mm will be stuck on top of that. So new tile thickness will be 5mm, so substantially thicker but with good reason.

by (Martin Raynsford) at 06 April 2015 03:00 PM

05 April 2015

Kate Bolin hackergotchi for Kate Bolin

Finally finished my second pair of Jaywalker socks. These are in...

Finally finished my second pair of Jaywalker socks. These are in the Jubilee colourway of King Cole Zig Zag, which pretty much looks like something the US Army would sell at Captain America shows trying to get women to knit more socks for soldiers.

It is sooooo tacky.  I love it.  And I know that the yarn’ll last, because I have another pair of Jaywalkers in Zig Zag’s Cornucopia, which is like the 70s exploded in a pair of socks.  But so comfy and so durable.  So I’m hoping these are too.

05 April 2015 07:29 PM

Martin Raynsford hackergotchi for Martin Raynsford

Rustic Dice 2

With the dice principle proven I moved on to actually laser cutting the dice for the game. The is a Vale LRP version of Zombie Dice, you try to get treasure before being attacked by the Octopus or before the treasure escapes on a boat. There are two styles of dice shown here, one set is engraved and outlined and the other set is just outlined. Doing one dice at a time and all 6 sides was actually quite time consuming, with more regular dice all 13 could have been engraved at once which would have cut the time down. It's also interesting to note that the engraving took 20 seconds per side but the outlining only took 10 seconds, it's 3 times longer to colour the shapes in and that really impacts on the price of any such work.

The game looks fun though and I can't wait to play it next time I'm at a Vale event.

by (Martin Raynsford) at 05 April 2015 02:35 PM

Project #4, Functional Machine

The Blacknose laser cutter has now been stripped down and deconstructed, all of the essential parts have been moved across to the new base plate and everything has been reconnected. This machine is now functional. It's mostly a good indicator to show that nothing was damaged in the transfer, it's still wired in using the Leetro controller but as we already know that's easily switchable

The next phase is to shorten all the wires and find new places to mount all the separate parts of the machine so that they all fit back into the cover.

The E-Stop is now conveniently located just on the floor down there, just in case of really bad emergencies.

by (Martin Raynsford) at 05 April 2015 12:16 AM

04 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Rustic Dice

I've been making some custom dice as a favour for someone, mostly to figure out how to do it and to see how they come out. I believe these cubes were approximately the right size and within budget. They're not very cube shaped and are a bit rough but we can call them rustic and they still happily fit in a LRP scenario. The problem is lining them up under the laser, because they're all slightly odd shapes it worked out easier to do them individually and of course one face at a time. I made up a frame, using magnets and scrap, the magnets at an angle push the scraps together and pinch the dice. The images are close enough to the centres of the dice for any misalignment to not matter. The result is fairly effective but these odd shaped cubes won't be going in to production any time soon.

by (Martin Raynsford) at 04 April 2015 06:27 PM

Project #4, Hardware transferred

Another productive evening on the open source laser and I managed to transfer all of the hardware from the Blacknose base to the new Blacknose plate. This is an exercise in drilling and tapping holes (putting screw threads in them). The XY gantry is across, the mirrors and the tube mount. Tonight I hope to move the existing electronics, I doubt I'll find time to turn it on as well but it's all good progress.

by (Martin Raynsford) at 04 April 2015 02:15 PM

03 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Rifled Barrel for #MFUKLC

Continuing my build for the Mega Fun UK Laser Challenge I built a barrel for our ping pong ball gun. The barrel is made from dozens of stacked slices, I used a section of 41mm waste pipe to help keep them all aligned (I cut a slot down the side to make it fit neatly into the barrel). As I was stacking them I realised that If I twisted them round I'd get a fancy styling on it. Yes I realise rifling should be on the inside but in this case it wouldn't work anyway so this is just to look good.

by (Martin Raynsford) at 03 April 2015 09:59 PM

02 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Project #4: Major Blacknose Modifications

In addition to my open source controllers for the Blacknose Laser cutter I'm giving my machine a major overhaul. As you can just about make out I'm taking all the parts off of the machine on the right hand side and placing them all on the plate on the left. This should reduce the height of a Blacknose by about 50%. It'll also leave a hole right through the base of the machine so in theory you could just put the laser in the middle of an extra large sheet and let it cut that.

Now all I need to do is figure out where I'm going to rehouse the extraction and all of the control electronics which currently live in the base, no big deal really :P

by (Martin Raynsford) at 02 April 2015 09:48 PM

01 April 2015

Martin Raynsford hackergotchi for Martin Raynsford

Z Controller Software

I've not really written any PC software since I quit my job a year ago and I've quite enjoyed making this little program for the Z controller. I'm pretty much at the final revision so I thought I would describe some of the features.

Firstly and most importantly the software is able to detect the presence of the Z controller. The Z controller is an arduino nano, this means it has a USB to serial chip on it and it can be plugged and unplugged at any point. The PC controller detects removal and arrival of USB devices and uses those notifications to check that the controller is still attached. It gets a list of current serial ports and attempts to open them all one at a time, if successful it pings the device with a "?".  If the Z controller is on the other end of the port it replies with "Z Controller" and the PC knows it has found the device. The status is updated in the square at the top which show green/pink for connected/disconnected but it also gives a tool tip text response too.

The interface was intended to be very straight forward, there are 6 buttons, vertically aligned. The numbers represent how many millimetres the Z axis will move when the button is clicked, the top 3 move the bed upwards, the bottom 3 move the z axis down. This is similar to the way the 3D printers work and inspired by the pronterface controls.

Because this is really going to be used to drop the z axis by a specified amount between cutting layers (allowing for n passes of a thick sheet of material) I added a text box on the bottom which you can enter a specific value in to. The value is parsed to make sure it is a numeric value, again with pink/green qualifiers. The actual value is sent to the controller when you click the Green +Z and -Z arrows.

So if you want the Z axis to drop 2.5mm change the value in the text box and click the down arrow.
The User Interface is designed to be skinny and unobtrusive so it can sit on the computer and not get in the way of Lasercut or CAD package. This means the program can't have a header like a normal window (but it still appears on the taskbar). 

When you hover over the middle white button the cursor changes to arrows, if you click and drag this button you can move the form around to wherever you want it. When you release the button the form stays in that location and it remembers where you left it when the program closes.

A menu system pops up when you right click the middle button, this allows you to close the program but also decide whether the program should be displayed above all the other programs. This means it can stay on top of Lasercut even when Lasercut is running full size. The program also remembers this option when the program closes.

by (Martin Raynsford) at 01 April 2015 09:45 PM

31 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

40W Handheld Laser Cutter

My most recent project again has gone up over on Just Add Sharks but it's too good not to at least warn you guys about it.

by (Martin Raynsford) at 31 March 2015 11:00 PM

Matt Little hackergotchi for Matt Little

Mini Amplifier Kit

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This is a simple, low-cost amplifier kit based upon the LM386 amplifier IC.

It has a maximum output power of 1W, which is good enough for amplifying mp3 players, phones and also the beeps and sounds from microcontroller projects.

This kit has one surface mount component, the LM386, which is good for those learning to solder surface mount components. The rest of the parts are through-hole.

It is available for just £6 (including delivery within the UK).


by (Matthew Little) at 31 March 2015 08:57 AM

28 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

Custom Z Controller 2

I was expecting to make changes to this device but I wasn't expecting it to happen so soon. I've now made 3 of these devices at peoples requests. I was thinking about how it connects in to the leetro controller and I realised if I connected to the original controller I could duplicate the signals coming from that too. This would allow me to adjust the Z controls using the PAD03 panel the same as before. I can also draw power from the leetro controller so even if the device isn't connected to the PC the whole thing still works.

by (Martin Raynsford) at 28 March 2015 09:44 PM

Custom Z Controller

Lasercut 5.3 has a bit of a slack way of dealing with the z control, you nudge it up and down a bit until it's in the right place according to the height tool. The amount depends on how long you hold the button for. One of our customers wanted to be a bit more specific about how much the Z axis moves, that way they could make 5 passes on their material and drop the Z axis by 1mm each time. So I made them a custom Z axis controller, this one connects to the PC and allows you to send specific mm commands to the Laser cutter. The PC end is a simple interface that allows you to send 0.1, 1 and 10mm commands to the controller, but it also allows you to send a custom distance. (software bundle here)

The PC controller actually detects when the USB serial port of the Arduino is attached and removed and it opens and closes the serial port appropriately, this means you can leave the program open all the time. The laser cutter, softdog dongle and Z controller could also all be attached to the same USB hub so you only need 1 wire running to the laptop while cutting.

by (Martin Raynsford) at 28 March 2015 12:23 AM

26 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

Wolf Shield

More shield detailing in the same vein as this pheonix

Also some completed works after latexing

by (Martin Raynsford) at 26 March 2015 10:30 PM

25 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

Suontaka Sword

A guard and pommel for a suontaka style viking sword (I realise the guard is upside down)

by (Martin Raynsford) at 25 March 2015 10:17 PM

24 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

Labyrinth Rubber Stamp

By request I made this rubber stamp featuring a labyrinth pattern, my inkpad isn't quite big enough to test it (60mm diameter) but it looks good.

by (Martin Raynsford) at 24 March 2015 10:08 PM

Matt Little hackergotchi for Matt Little

ACS758 Current Measurements

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I've been designing a breakout board for the ACS758 hall-effect current sensor. The first few prototype boards came in and I decided to give them a quick test. The results were not quite as I expected so I thought I'd put write about them here, for others that might be using this IC.

These current sensors come in a number of ranges (50A,100A, 150A and 200A, all with uni and bi directional variants). They use the hall-effect, which measures the change in the magnetic field to measure current. This means you do not need to install a shunt resistor, with its associated power loss and voltage drop.


by (Matthew Little) at 24 March 2015 03:24 PM

23 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

Elucidator Cosplay Sword

This is a cosplay version of the Elucidator Sword, (hopefully that sounded like I knew what I was talking about. It's another Eldritch sword though so I'm sure it'll be awesome when it's done.

by (Martin Raynsford) at 23 March 2015 09:52 PM

22 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

Project #3 - Physical Space Invaders Game

After Donkey Kong, Pacman and Lunar Lander we were having a discussion about which other games could be turned in physical versions. So about 6 months ago an idea was forming in my head, more recently I've managed to get all the pieces into the right place to make it happen and my physical version of space invaders was born.

I've document the whole project over on the sharks blog because I've used a Whitetooth laser cutter, a rotary attachment and a break in board.

So you can check out the whole project here

by (Martin Raynsford) at 22 March 2015 08:24 PM

18 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

@rideworks - Anodised Aluminium

I had a very spur of the moment visit today by Paul from Rideworks. He wanted to know if our machines were capable of engraving his anodised aluminium parts so the best way to find out was to try it. We played around with a few different speeds and settings and we even cut an impromptu jig to align the parts perfectly. The test results are great, in fact the hardest part of the process was the moving of files between our aging laptops.

by (Martin Raynsford) at 18 March 2015 02:48 PM

17 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

@MFUKLC - Ball Feed Joint

My Ping Pong ball cannon is all about the throughput so I need a nice clean way to feed balls into the mechanism. This 41mm diameter sweeping bend was manually sliced in inkscape, cut and assembled in just 2 hours, 3D printers eat your heart out. I can't wait to bodge it into my cardboard mock up and see what improvement it makes. #FDMPrintersSuck


by (Martin Raynsford) at 17 March 2015 11:05 PM

Matt Little hackergotchi for Matt Little

Solar workshop with EWB Nottingham

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I have run a number of solar photovoltaic and off-grid power hands-on workshops and I recently ran another solar PV workshop with EWB Nottingham. This was a two hour workshop run at Nottingham hackspace.

Engineers Without Borders UK (EWB-UK) is a student run organisation trying to connect engineers with the field of international development. They do this through placements, training and outreach programs.





by (Matthew Little) at 17 March 2015 10:25 PM

15 March 2015

Martin Raynsford hackergotchi for Martin Raynsford

Letterpress Game

I was initially asked to make 3 sets of alphabet tiles for a friend, but after a bit of digging I discovered they were making a physical version of the letterpress game. Something that you could take to a medieval field and not feel out of place using. I ended up making the tray and 3 sets of letters in different woods so it would be obvious who placed which letter. It looks rather neat, I hope to play a game with some point if/when I make it to an event this year.

by (Martin Raynsford) at 15 March 2015 11:40 PM

Steve Barnett hackergotchi for Steve Barnett

Hot Wire Cutter

While building my model SpeedTwin ST2 I needed to neatly cut some foam. Since I had a bunch of 6mm laser safe ply available and needed to cut some other bits the next day I decided to design my own hot wire cutter and cut the parts out at the same time.

Hot wire in CAD

The cutter is designed to be built around some 1/2inch spruce engine bearer stock that I had lying around. Any roughly 1/2inch square section wood will work so long as it is stiff enough.


Most of the parts are designed to be built from 6mm ply, with a few 3mm bits. 6mm, 3mm and 2mm bolts are used to attach the fittings to the wood. Some nichrome wire is used as the heating element, with some stiff wire on the other side to tension the cutting wire. I added some springs to help maintain the tension as the wire stretches. These would work better on the other side to that shown in the photos to increase the amount of wire available for cutting.

Hotwire results

I’ve found lots of articles online about DIY hot wire cutters that suggest using a transformer connected directly to mains, with no current limiting or anything. DO NOT DO THIS. Those people are idiots (and they’re most likely in a country with a lower mains voltage). I’ve been running my hot wire from a lab power supply in current limited mode and it works nicely and gives excellent control over the temperature of the wire.

I’ve uploaded the DraftSight files to my GitHub account for anyone who is interested in them, but please bear in mind the finished product could be dangerous and I take no responsibility for what you do with it.

by moop at 15 March 2015 09:58 PM


Foobot is a project I started around November 2014. It’s still a work in progress, but the time when I should have written it up is more than due.


Foobot is robot table football game, with two teams of two tiny adorable robots. The robots are controlled by classic Nintendo and Sega controllers, hopefully it can can finally settle the age old console wars. :)

Foobot Robots

The intention eventually is to build some games around these robots. Possibly with the ability for a computer to control some of the robots via some image processing if I’m feeling really ambitious.

The robots are built around an ATtiny2313 microcontroller, with an SN754410 to control the motors and a cheap 1402 433mhz radio receiver module. This is mounted on a simple laser cut perspex frame with two wheels mounted directly onto the motors.

Foobot Parts

The initial design was built on stripboard, but once I had it working I ordered a professionally made PCB via This was the first PCB I’ve had made and the quality turned out to be better than expected for the price and the 3 week shipping was pretty bearable.

As the radio modules are very simple (and one way) I decided to avoid the problem of collisions between multiple transmitters by attaching the controllers for all players to a single radio transmitter. The transmitter reads all of the controllers and then sends a packet addressed to each robot in turn. Messages for the robots consist of a robot ID, the message payload and a checksum. Robots ignore all messages not addressed to them and any messages with invalid checksums. Dropped packets or interference are dealt with by hoping the next message with more up to date data will arrive.

Transmitter Unit

The transmitter module is based around a tiny 8 pin ATtiny13 microcontroller. This has just enough pins to read data from all of the controllers and to send a signal to the transmitter module. Some of the lines are shared with the In-Circuit Programming interface for the microcontroller – these were chosen to be the outputs so there was no need to worry about other hardware interfering with programming.

In order to read 4 controllers with 4 pins the transmitter uses a pair of controller interface boards. These have a socket for a NES controller (which contains a shift register so the button states can be read out serially) and a 74LS165 shift register which enables the Master System controller to behave like a NES controller (it is just 6 buttons with a shared common pin). The 75LS165′s latch line is inverted so a transistor was required to invert this in order for the same latch signal to operate both devices.

Transmitter Parts

With this setup the only extra pins required on the microcontroller are shared latch and clock signals and a data line for each NES/Master System controller pair. The serial output from the NES shift register is passed into the serial input on the 74LS165 so sending a latch and 15 pulses reads 8 buttons (2 unused) from the Master System controller and then 8 buttons from the NES controller. The Master System buttons are mapped so they come out in the same order as the buttons with equivalent functions on the NES controller (A, B, Select, Start, Up, Down, Left, Right and 2, 1, N/A, N/A, Up, Down, Left, Right).

In the case of the transmitter the circuit was initially tested on a breadboard. This proved quite fragile due to the flying leads to the various controllers so I ordered some more custom boards. The price break on DirtyPCBs is at 5x5cm, so I designed a single board containing the controller interface and a board to carry the microcontroller in a single 5×5 square. I designed tabs into the board outline to allow the two boards to be broken apart. When fully assembled the transmitter contains two of the controller interface board and one of the microcontroller board, so there will be some spares of the smaller board. The cheapest quantity from DirtyPCB is a protopack of 9-12 boards (I got 11 both times), but I only need one transmitter currently so that works out just fine.

I struggled to motors that are both cheap and small without a ridiculously high RPM. The motors I settled on in the end run at around 16000 RPM and 9 volts. Because of this I had to add some code to pulse width modulate the enable pin on the motor controller. Turning requires very little force so it runs with a very low duty cycle. When moving forward initially the motors run at full power to get the robot moving, after a short delay the duty cycle is lowered to avoid accelerating too fast.

Tuning the PWM settings has proven fiddly, and testing with the programmer attached is almost useless as the wires affect the motion of the robot too much. Because of this I implemented an over the air update of the PWM settings. This added some extra commands to update the PWM duty cycles over the radio, and a command to write the to the microcontroller’s EEPROM to save them permanently once the behaviour feels right.

I’ve uploaded the project to github, including all of the code, schematics, PCB layouts and chassis/case CAD files. Feel free to use these, but please bear in mind that the project is still a work in progress.

Finally, here’s a video of some Foobots in action (before the over the air PWM tuning feature went in):

by moop at 15 March 2015 09:25 PM

Martin Raynsford hackergotchi for Martin Raynsford

Carcassonne - The Castle Meeples

Just a quick post, it's been a busy week I've been out delivering lasers to people for Just Add Sharks (more to deliver next week too). I also have a great monthly project I've been working on which is very nearly finished so please accept these simple meeples for the week :)

by (Martin Raynsford) at 15 March 2015 04:42 PM