AD371 - Shoreham Fort

This is a university project base around the Napoleonic fort at Shoreham beach on the south coast.

With a final goal of building a film studio/school of some description our first task was to create a 'camera device' to observe and interact with the site.

I conceived a device which would use the existing railings on site to take long tracking shots.

The main problem to overcome were the large lugs where the rail attached to it's posts.

After a few weeks of prototyping I set about laser-cutting my creation from MDF.

The main design consisted of several of theses notched wheels. Each wheel has four sets of bearings which sit on the rail and allow it to roll along.

When the device reaches one of the lugs on the rail, the large notched wheel will rotate, stepping over the lug and landing on it's next set of bearings.

A series of neodymium disc magnets are used to confine the wheels to 90 ° rotations, to ensure that they are always sitting properly on their bearings.

Device on site

The final device has 3 sets of 3 wheels. Each set is distributed around the rail to grip it firmly and provide a smooth ride.

The long legs help add balance and keep the lower sets of wheels in contact with the rail.

And finally here is a gif of the crawler working.

My crawler device was grouped together with two others, a camera mount that was triggered every time the crawler took a 'step', as well as a pedal powered drive system.
Whilst the camera mount worked relatively well, we had trouble rigging up the drive in the pouring rain (bad timing for our final installation).

I made another trip on a sunny day to get these pictures, but didn't have the other parts.

Still I'm pleased that the stepping action performs as intended.

Stargate Kull Disruptor - Magazine & Finish

Part 1 | Part 2 | Part 3



I had planned to make another one of these and document it better, but until then I figured it was best to have some pictures of the final piece up.

The final part to be built from plasticard was this magazine type piece, that holds the power cell.

After that was finished, I cast up a copy of everything, scavenged a weaver rail mount and set about painting.

The paint job was rushed and doesn't really have the proper depth, but with a few tips from veteran Zat painters I should be able to do better next time.

But for now I'm mostly happy with how the project turned out.
Still on the to do list are:

• New paint job (got some suggestions and new paints ready)
• Draw up circuit board for lights and mill with my CNC machine
• Scavenge the perfect part for the clear plastic lens 
• Remake the moulds for the main body, it has one or two shocking air bubbles.
• Mill a new powercell out of brass. (Even a small bit of solid brass is prohibitively expensive so this one is unlikely)
  

If I can manage just 3 of those things I'll have a really nice piece.

Part 1 | Part 2 | Part 3

Hellboy Corpse Locator Tutorial - Part 3

Part 1 | Part 2 | Part 3

The following steps are lacking pictures, hopefully I'll be getting on with my personal build-up soon and can finally fill in these last few pictures. But in the mean time I'll describe the process as well as I can with what images I have.

Hinges

Now that everything's painted you can start to put it all together. The first step is to distress your hinges a bit. bend them around with some pliers, give them some good dents with an awl and finally, hit them with a blowtorch to ruin that overly shiny finish.

Image: distressed hinges

Now that they're good and wrecked you can screw them back into place. I like to add a bit of epoxy glue as well, just to make sure it stays in place. Also it fills in the hinge slot a bit.

The bearing plate gets glued into the bottom of the main body. Nothing too tricky here, just make sure not to use too much glue, you want the plate the be flat against the body, if its on a layer of glue, it may end up too high, or at an angle. And just try to centre it within the space, (there's not actually much wiggle room, probably only 1mm each side)

These hinges didn't get pre weathered, so they stick out.

Depending on how tight of a fit your bearing is, you may not need to glue it in, however I have found that the added weight of the centre dial assembly can cause the bearing to rack within it's housing, so just use a dab of glue around the edge to seat it in it's housing.
Make sure the bearing is seated properly, nice and level, and be careful not to gum up the bearing with the glue!

The Centre Dial Assembly

This is where we assemble the centre dial, dome and bearing disc into one piece.

If you're building a kit with light, scroll down to the light module section and have a read through. In the past I have put the lights on before glueing this all up, but have now decided it makes more sense to add the lights last, but you may as well have a read and decide for yourself which way round to do it.

The difficult part of this step is glueing the pieces together so that the pin of the bearing disc is perpendicular to the rest of the assembly, otherwise your dial won't stay level as it spins (there are lots of factors that could contribute to this, but screwing up this step is the most likely cause).

When I say 'glue' in the following steps I'm referring to clear 5 minute epoxy. Strong, sets up fast, and not as noticeable if some leaks onto your dome.

You have to do this all in one go, so read through this all before starting, get everything ready and make sure to mix up enough epoxy.

Firstly, put a few blobs of glue on the back of the dome and firmly press it onto the face of the bearing disc.

Next apply glue to the edge of the bearing disc, don't put it on the inside of the centre dial and be careful not to get any on the dome.
Carefully lower the centre dial over the bearing disc and dome (I do it this way so the dome doesn't fall off). and push the bearing disc into place.

Just going by eye try to push the bearing disc in so that it is flush with the back of the centre dial.

I then clamp the whole assembly to something flat, to keep the bearing disc and centre dial flat, flush and aligned. A board with a small hole in it would be ideal, but I just clamp two metal rulers to the assembly, (separated by a piece of paper so the rulers aren't glued to the piece)

Once the glue has dried, you can remove all the clamps, tear off any paper that got stuck and simply push the post into the bearing you previously glued into the main body.

If you want to leave your mark, this is the perfect place, accessible, yet hidden

Weathering

Your compass should now be fully assembled, all that's left to do is weather it. Obviously there's lots of room for interpretation here, so I'll just detail the basic techniques I use.

My main method of weathering involves mixing up a turquoise paint with plaster in it, then stippling this onto the compass.

The first pass is a watered down, almost black tone, with very little plaster in it, I use a big stiff brush and stipple pretty hard, trying to get into the deep recesses . About 90% of the exterior gets this treatment. Then using a damp sponge I wipe down the surface detail of the compass, leaving it just in the low spots.

On the next pass I'll lighten the tone of my paint and and thicken it up a little with plaster (note: the more plaster you add to paint the more is will lighten as it dries, so be careful)

This is where I begin to try and tell a story, the mould and oxidation will have started in one deep area, and slowly crept to another, The hinge will have trapped water and gotten really gunged up. The inside will have less of the light coloured fresh, mould and retain a bit more of it's golden sheen.
As I work I constantly wipe the surface of the vines with a damp sponge, so that you keep some shine to the piece.
There tends to be a bit of a gap between the dome and the centre dial, I like to get lots of mould in there, even letting a bit of it creep up onto the dome.

After a few layers (if you do this slowly you will get some really nice plaster 'mould' deposits building up) I'll have worked my way from almost black, covering all the deepest recesses, up to almost white, just barely touching the tips of some mould that's crept onto the surface.

These pictures are by no means a step by step guide of what your trying to achieve in each pass. They're just a reference of how I start building up the layers (there's lots of tweaking after most of the paint is laid down that I didn't document).

Light Module

If you've bought a light kit, one of the last things you need to do is fix it in place. I personally like weathering to be the final step, but installing the lights shouldn't do any damage if you want to do that last.
First you'll need to drill a few holes. Download this template and print it out at 100% . Make sure you've sized it correctly by measuring it against your light module. (note: the template will only work for the newer milled light modules, if you have an old perf board one, you'll have to use the board itself to help you get the holes in the right place, they're all a bit different).
Once you're sure that the template is okay then use it to mark up the reverse of your bearing disc. Make sure to line the switch up with one of the notches in the dial. If you get the orientation wrong, then you'll have to remove the centre piece if you want to turn the lights on, where as if you line it up with one of the notches you can turn the lights on with a toothpick or pencil etc.

When drilling be careful how you hold the dial assembly, I place a rag underneath so I don't scratch the dome.
The large holes should be 3mm and the smaller holes should be slightly smaller than the supplied screws (that's the silver ones not the brass ones). I've found 1.6mm to be about right.
Neither of the holes should be drilled all the way through, the 3mm holes only need to go deep enough to punch through the white plastic layer and into the clear (for older kits only drill as deeps as is needed for the LEDs)
And the smaller holes only need to be about 4mm deep.

Once all your holes are drilled you can drop your light board in and tighten the screws, don't overdo it, so long as the board doesn't wobble, you're fine.

*Due to some tooling errors you may need to widen the 3 small screw holes in your light board. The screws should turn continuously in the board, and bite into the bearing disc. If the screws are biting into the light board too much, then widen the holes.

Part 1 | Part 2 | Part 3

Milling PCBs and Circuit Board Evolution

I've been dabbling in electronics for years. Most of the time this involves starting on a breadboard and then transferring your finished circuit onto stripboard.

More often than not I'm trying to squeeze far too much stuff into a tiny space, for example in my Zippo Burglar Alarm.
Which means that the resulting boards are an awful mess of wires and massive solder lumps.

For this post I'm going to use my Hellboy Corpse Locator light board as an example, because it's been through a fair few revisions.
It's a fairly simple piece, I needed a board to fit under the dial of my corpse locator prop, and make the dome light up red. A simple task electronically, but mechanically it's difficult to get everything to fit.

I started by using a tank cutter to cut disks out of stripboard.

I was surprised by how well this worked, it made it easier, not having to shape each board by hand, but each one still took about 10 minutes.

I wanted to use surface mount LEDs, they were on the copper side, meaning everything else was on the reverse side. Which left me trying to find a way to create a second battery contact on the reverse side of the board.

The most reliable solution I could come up with was stitching a grid with copper wire.

Again, at the time, I was proud of my little inovation, conductive paint had too much resistance, glueing foil to the board had been problematic, this wasn't perfect (some wide copper tape would have been good) but working with materials at hand it did the job.

Once everything else was attached, the board looked like this. 

After making about 10 of these I managed to get them quite neat. But it was very labour intensive, each one probably took over 3 hours of quite fiddly work. 

And due to the nature of cutting out the boards, each one was slightly different, in where the LEDs went and where the wires were routed.

Many months later, the dawn of my CNC machine, and obviously one of the first things I wanted to have a go at was milling PCBs. I drew up the design in Vectorworks (EagleCAD* is the proper tool) and bought some copper clad board and was very easily able to cut out a simple PCB.

Milled PCBs are different to proper manufactured PCBs, you start with a solid layer of copper and simply mill away 'isolation paths' to create your tracks.

The one on the left is my very first attempt, I just used a cheap V bit that I had and the result was some very rough looking paths, but an entirely functional board.
My second attempt (using a 0.8mm ball nose) was much neater, but after my PCB milling bits arrived from China I was able to cut really neat boards. These are 0.2mm isolation paths, so potentially I can mill some really complex boards with lots of tiny surface mount parts.

Designing for CNC always affects your design. For example I wanted to take advantage of the fact that the copper layer could act as my other battery contact (no more stitching) so that meant the board was flipped and everything was soldered on the back. 

This also meant I had to switch to normal 3mm LEDs and mount them upside down (poking through the board) I originally use smt LEDs to keep the board thin, but the limiting factor is always the battery thickness so this works out fine, and the 3mm leds are brighter.

The boards look really cool now, very neat and I can do cool stuff like engrave labels and my logo. But the main thing that makes these far better than their predecessors is the time they take to produce. Each one probably takes about 20 minutes of milling, because it requires several tool changes. But then only about 10 minutes of soldering and it's finished.

Also each one is identical, which means I can add matching screw holes to my plastic corpse locator parts. rather than the tedious task of lining up and drilling each individual part to match it's specific board.



* Eagle is a program which allows you to draw up circuit diagrams, as well as layout circuit board designs for sending off to have fabricated. With the proper add on you can also create Gcode to send to a CNC machine. It sounds like a fantastic tool, but when I had a go there was a lot to learn and, for such a simple circuit, with mostly through hole components it was just slowing me down.

CNC Mill Build - Enclosure

After finally getting the mill running it became obvious that I was nowhere near done.

Firstly, in their current position the electronics didn't give the machine enough room to move freely, so they would have to be relocated.

Also my current method of using drawing pins to hold down material wasn't going to be a permanent solution.


The first problem is easily fixable, I collected a bunch of connectors, then got out my calipers, cracked open Vectorworks* and began designing an enclosure. 
I cut all the pieces out of 3mm MDF and when assembled they looked like this.

From the front all you see is the name and power switch.

One side features a cut out for a fan.

The back has all the connections, A/C power in, parallel signals from the computer and five molex connectors, one for each motor and one for the limit switches.


I designed the box to be low profile so it would fit in the sliding drawer under my desk.

Here it's nice and out of the way but easily accessible if I need to fiddle with it.

Under the hood, you can see the power supply takes up most of the space. Main power is routed through the illuminated switch at the front. The 24V supply then gives power to the motors, it also drives a tiny 5V regulator for the logic power supply and the motor is supplied by a slightly larger 12V regulator (you can see it glued to wall on the right)

I found some little fuse holders and intend to put a small fuse in after the switch. There's also room at the back for adding more connections, for things like spindle control and an emergency stop button.



Being the first real thing I've made with my machine this taught me a lot. Firstly my machine is pretty damn accurate. 
The pieces just fit, I was expecting to have to sand things, but they actually fit great and I measured the pieces to be well within 0.2mm of what I intended, that's nowhere near what some CNC machines can achieve but with MDF it's more accuracy than I'll ever need.

Another thing to note is, always measure your material. I should have remembered this from when I designed stuff for laser cutting, but my 3mm MDF turned out to be 3.2mm, so my box joints aren't quite flush.

A lot of time designing this was spent on the engraving. The majority of fonts these days are solid blocks, you can turn them into outlines with a vector program, but the best results are achieved from single line fonts. You can see that the axis labels I engraved on the back of the box are a bit chunky, I didn't like that so I spent a while manually creating single line letters for my title font.

This was tedious but I'm happy with how the final thing came out.

The M⁶ for short

I'd like to make the lettering black so it pops more, but I can't think of a good way to do this, hand painting would be tricky, and detract from the nice clean finish.

The easiest solution is to mill all the way through a material and place black behind it.

I also installed a hold down table. Essentially this just involved sinking a bunch of t-nuts into the back of my board in a grid. I now have a grid of points where I can bolt things down to the table.

Above you can see me marking out holes, and a couple of nuts ready to insert.
The grid is now finished, I'll snap a proper picture next time I'm using it.

I've actually found that for most materials  double sided tape is a better solution, most of the time the clamping bolts just get in the way.


I've been happy with this set up for the past few weeks, I've had a go at milling a phone dock, pcbs, and at the moment I'm milling maps out of cork. :D

One thing I haven't really tried is milling plastic, I've got some chunks of acrylic on the way so that's next on my to do list.


*Vectorworks is my CAD program of choice, mainly because it's what I used during my architecture degree. However it seems that I'm in the minority using this program. Most people use AutoCad or SketchUp, or for simple 2D work, Inkscape.
Supposedly AutoCad was designed by engineers and Vectorworks by architects.
I've got a copy of Illustrator, but most of the time I get frustrated with the alien pen tool, give up and switch back to Vectorworks.