Monday, 27 February 2017

Calibrating the LS3020 HPC Laser cutter

It was with excitement and bated breath that we set up the laser cutter last night; it's not been used for a good while, had come back from the unit covered in about an inch of thick, black, sticky dust, and we had no idea what state it would be in.

It took ages to clean it to a workable condition, but everything went back together easily enough. The LS3020 is a great little, quiet machine. Maybe it's because the bungalow is still pretty empty and possibly a bit echo-y, but our air-pump sounding like someone revving a motorbike inside! No matter how we tried strapping it down, it was really noisy.

now the air-pump is almost silent!

A long while back, we made some laser-cut western buildings for tabletop miniature gaming and instead of painting and adding fiddly little details, we slapped some homemade stickers on them. They looked quite nice.

But some of the larger buildings - particularly those with lots of legs or cut-away shapes - were always quite fiddly to get the stickers to line up perfectly. We spent hours messing about with the bitmap images and the RoboCraft software, trying to get the stickers to fit onto the laser cut shapes "just right".

It turned out that the laser cutter wasn't carving to exactly the right sizes!
So once the machine was connected up and we'd checked the usual - made sure there were no air bubbles in the laser tube and so on - we first the old thing up and carved out a 32mm circle from some 3mm acrylic.

The laser cutter is still beautifully silent. And at 15mA we're easily cutting through 3mm acrylic at about 18mm/sec. Once cut, we turned the circle around inside the plastic surround.

At about 90 degrees, the circle started to bind on the top and bottom (while at the sides you can see the gap is fractionally wider). This is the first indication that we're cutting wider on the horizontal than the vertical. The old laser cutter was going to need recalibrating!

Calibrating the LS3020 is as simple as cutting out a 100mm square (we used 3mm mdf this time, as the material is cheaper and we've plenty of it).

On both edges, we were less than a millimetre over-sized.
After changing a few values in the properties dialog of the NewlyDraw software and repeating a few time, we managed to find the best DPI values to get our square, well... square.

After which, our 32mm circle cut to exactly 32mm diameter, and rotated freely about it's surround, with no binding at all. The whole process took about 20 minutes. But had we not done it, it's quite possible we'd have wasted hours trying to fit multi-part assemblies together, as each part would be fractions of a millimetre out; not enough to be noticeable individually, but enough to through the whole assembly out once all the cumulative errors had been added together!

Now the next problem to solve is how to free up enough hours in a day to finish the bungalow, make cool stuff with the laser cutter and move everything in from the unit/lock-up storage, before we have to go away for a few days.

It's raining and there's still tiling to finish around the base of the workshop. And trim around the windows. And guttering along the roof. But the laser cutter is up and running and we've been preparing a stack of dxf files just for this day......

So much to do, so little time!

Sunday, 26 February 2017

29 x the cool

Anyone who knows me knows I love the Wildhearts (except, perhaps, their late 90s diversion into that weird white-noise-metal) and I think one of my inheritance tracks would have to be "29 x the pain" (nerd fact: it was actually released as a B-side to the Suckerpunch single, which I never believed to be one of their best tracks).

So here's a quick post showing how, overnight, the workshop bungalow suddenly got about 29 times cooler

My laser cutter finally came home. Yay!

Saturday, 25 February 2017

Bungalow workshop taking shape

Fewer blog posts for this month doesn't mean we've been idle. Pretty much the opposite! Work on the bungalow has continued at quite a pace and we're almost ready to start thinking about moving in. As with the walls, Cat from Freegle really came up trumps this month, with some massive heavy-duty desks.

The first and most obvious use for these was for worktops. But before we could build our worktops, we needed to make sure the floor was good and level. Which it wasn't. So, with a bit of lateral thinking, we set about cutting them up to make a nice, solid, warm, level(ish) floor!

A few battens not only meant we could easily join all the wood together easily, they also helped lift the flooring off the stone-cold concrete base (hopefully this will help keep it from getting too cold in the winter months) and even out any "undulations" our rough-and-ready concrete pouring might have created. To finish off, we'll be putting some interlocking yoga-mat-style-foam floor tiles down which will not only tidy things up, but also help improve thermal insulation.

All the desks we got from Cat were a solid 22mm thick chipboard, with laminate on the tops and edges. We used up pretty much all of the first lot with just the floor. So it was only after a second visit to collect yet more that we had enough to build our worktops.

Unlike the flooring, we decided to keep the curvy bits on the desk lids this time - even going so far as to cut one to a custom curved shape for our standing-height worktop, just to fit in with the "style" of the workshop!

Check out that curved work surface on the right. And all for no other reason than aesthetics. Steve's not the only one who can make things look nice! (although he is very good at it)

The total floor space of the workshop is almost double the size shown in the photo, we've only managed to fit out about half of it yet.

No doubt we'll have to move some shelves around after the laser cutter has come back and been installed. And things will probably get dismantled to make room for some of the bigger bits of machinery. And, of course, before we can use any of it, we'll have to get that electrical wiring finished off.....

Thursday, 23 February 2017

PCB Fab in a Box

A while back we changed printers. It wasn't by choice. But Steve busted up the desktop Dell and made it useless for press-n-peel toner transfer - so we went for a new Xerox 3260. As you'd expect from a Xerox, it works well, even with our cheap Chinese press-n-peel alternative paper.

Well, it did.
Until it got really, really cold recently.
And when trying to do toner-transfer in temperatures of about 10 degrees (it was -4 outside, so ten was positively balmy) we hit a few problems. The image transfer was suddenly really badly pitted - worse than even when we tried to use a (crappy) Brother laser printer!

So Matt suggested using some green film from PCB Fab in a Box. Matt had used the stuff in the past and swore that it would make good even a really badly pitted board. We remained unconvinced. But tried it anyway - running the green film through the laminator about four or five times, just to make sure.

The green transfer wasn't exactly successful - maybe we ran it through the laminator too many times, but the green film stuck in places we didn't really want it to!

So we tried again with some soic-to-DIP breakout boards.
As before, the toner transfer wasn't brilliant - plenty of missing bits in the copper pour areas, which would normally lead to pitting during etching.

So we applied the green film and ran it through the laminiator just twice. The results were  much more favourable this time.

And when the board etched....

... lovely, clean traces. Nice, large areas of copper pour with no pitting. The overall end result knocks spots off our usual toner transfer method. And at £9 for a 15ft length, the green film should last us a good long while, and help us make great looking PCBs for months to come!

Wednesday, 15 February 2017

Salvaging non-working SD cards

A little while back we were playing about with lots of different SD cards to use in a number of WTV020 sound modules. Frustratingly, from 45 SD cards, we had about a 50% failure rate.

There was no explanation - no reason why they didn't work; they just didn't. The SD cards were all formatted exactly the same way (FAT 16kb clusters) off the same machine, the files were copied on to them using the same method, and some worked and some simply didn't.

Ulrich Bien suggested trying to make a disk image of a working card, and trying to burn that onto a non-working card, to see if that worked. At first, it seemed like it shouldn't make much difference. Then, looking over our code from a few years back, when we created our own audio player and SD card FAT16 reader, something about boot sectors and zero-vectors came to mind.

It's quite possible that there's a difference in different cards - some may have to boot sector are sector zero, some may have an offset (this rang a few bells between a few of us who had been involved with the original SD card project, back in the day). Or maybe it's something entirely different.

But we downloaded Win32DiskImager and created an image of a working SD card. Without formatting the cards or any other further processing, we simply burned the image onto another SD card.

Sometimes we got an error.

It would seem that not all 512Mb SD cards are the same! Some have fewer sectors than others. So we found our smallest (working) SD card, formatted it (FAT, 16kb clusters), copied some files onto it and made an image of the disk.

We then burned that disk image onto our collection of SD cards.
Even though the image was taken from a 512Mb card, it burned onto a 1Gb card without a problem. Sure we're not getting access to the full capacity of the card. But then again, we're not writing to it either - we're wanting to read one of a selection of files. The extra card space isn't going to get used anyway, so it's no loss.

Surprisingly, we found that from about 60 SD cards (that were 512Mb or larger) we got 47 of them working. Some - the Nokia branded 512Mb cards for example - stubbornly refused to work; but many of the cards we'd written off as not working suddenly booted up and starting playing our wav files (ok, .ad4 files but it's the same thing).

So if - like us - you need to read data from multiple SD cards, there's always a chance that burning a "good image" onto them, rather than clean-formatting and copying files across could work for you too!

Monday, 13 February 2017

Bungalow workshop interior

After blowing a few quid on uPVC cladding for the workshop (which looks great now it's complete) and all the other costs, the bungalow fund is starting to get a little low. While, of course, it'd be great to spend plenty on load of cool geeky touches (inset LED lights, fancy panel displays, integrated cupboards and worktops etc) there's a very real danger that the fund will have dried up before that happens.

To take any slope in the concrete base away from the walls, I managed to snag some large 300x600mm floor tiles in Wickes. Tiles usually cost £30-£80 per square metre. At those kind of prices, we'd be spending about £200 (or more) just to put a skirt around building. However, thanks to Wickes end-of-line special offers, a three metre square section plus fixing adhesive and grout cost less than twenty quid!

Admittedly, the tile cutter to make them usable cost another thirty. But I'm calling that an investment - as it'll be perfect for cutting PCBs in future.

 cutting tiles with a rotary tile cutter is messy business! We dry-fit the tiles then (once again) the rain - and snow - made it difficult to carry on, so we'll stick these down when it dries up again.

Conscious of keeping costs from spiralling out of control, we went along to meet Cat who runs Freegle and just so happened to be clearing out one of the large council buildings in Hove. Although most of the furniture and equipment was spoken for, there were hundreds of shelves on the walls - all built from metal brackets and lengths of conti-board. Perfect for making shelving inside the bungalow!

As we got the boards back to the bungalow, there was the slight problem of having no walls in place, which was going to hold up putting the shelves up.

plenty of insulation should keep the workshop nice and cosy even in the dead of winter!

We worked out it would cost us about £200 in plasterboard - just for raw materials - to clad the inside. And that was just the walls. The ceiling would cost more. And then the whole lot would probably need skim-coating.

And all for a workshop - not a new living room or an extension on the house, but a workshop at the bottom of the garden. At first I thought OSB2 walls would be fine with a coat of paint. But it was then pointed out that it'd be a bugger for trapping dust and dirt. And it's heavy. And, at twenty quid a sheet, expensive too. What we needed was some cheap, easy-to-handle, easy-to-clean, not-so-heavy substrate we could simply screw over the interior of the carcass.

Something like contiboard....

We set about cutting the strips to length, and fixed them horizontally across the uprights in the walls. Although they're a bit rough-and-ready, with some trim on the edges (around the windows and on the external/internal corners where two walls meet) they'll be just fine.

Nasty vertical joins can be hidden behind either rack-mounted shelves, or under trunking used to carry the electrics (I didn't like the idea of the wires being embedded inside the walls as I didn't know whether the rockwool might react with the outer sheathing; plus having the wiring on the outside of the walls means it's less likely I'll drive a screw through it, when putting another shelf up in future!)

With all but a few lengths of conti-board used up, we're going to have to find something else to use for shelves in future....

The walls are still pretty grebby - they're going to need a good going over with a bucket of sugar soap - and they'll still look pretty ropey until we can get some trim on to hide all the nasty joins; but a whole load of (free) contiboard turned out to be just the thing to get it looking less like a wooden hut and more like a workshop!

Laser cut X-Wing (Lego) fighter

A little while back, we started making some light-up Lego characters. They're for a birthday in March, when Elvis turns five years old. While work continues on these (specifically, find the best way to make connectors in the feet) we got to thinking about making a laser-cut space ship or Death Star or something, for the light-up characters to go with.

And eventually stumbled across these great designs from breakfastsandwich on Thingiverse.

Amongst his awesome laser-cut Star Wars space ships are an X-Wing and a Tie Fighter. And better still, there's even a little Lego character inside the X-Wing! Perfect.

Except it wasn't quite - the designs are for 3mm thick material and the overall size of the finished spaceship is, frankly, massive (at least, for little five-year-old hands to play with). It looks great - the burnt edges and visible tabs and panels only adding to the "battle damaged, patched up" look. But it's just too big.

So we took the original designs, made some tiny tweaks here and there, and recreated his design in 2mm mdf. This immediately had the effect of re-scaling the entire spaceship to just two-thirds 66% of it's original size. At least it was more manageable for little hands.

The plans for this X-Wing are really, really nice. They're packed full of little tiny features (the way the undercarriage goes together is particularly clever). Everything lines up perfectly and the finished shapes are quite far removed from the usual blocky, square-edged appearance you often get with laser cut models.

We used PVA glue to put our test piece together - we figured it would allow time to re-position pieces should they need it - but the design is so well thought out and the instructions so clear and easy-to-follow, we could have put it together much more quickly with Superglue (no long delays waiting for joints to dry in between each section going together).

And, being re-scaled, the entire thing fits on just two A4 sheets of 2mm mdf. But given the number of parts and how small and fiddly they are, even just getting them out of the laser cutter proved tricky. We found the best way was to cover the sheets in masking tape before lifting them out - which ensured even the smallest little bits got lifted out and nothing got left behind (to end up inside the shop-vac hoover!)

The best bit? At 2mm, the rods and lengths of tube for guns and so on are a smaller diameter than in the original plans. But it turns out that lollipop sticks are the perfect size. And we needed at least eight of them. That was four lollies each!

Making sure the wings meshed properly took a bit of working out. But once they were in place, the wings opened and closed quite satisfactorily!

Even at 2mm, there was still room inside the cockpit for our Lego Luke. It was a bit of a squeeze (and there's no way the original cockpit cover would fit) but the character did fit inside the cockpit area.

So we decided to keep pretty much the entire design as per the original, and just devise some kind of new cockpit window to keep Luke in his seat.

A quick spray with some cheap white car paint (Poundland's slightly translucent, nasty cheap water-y white was perfect, as it allowed some of the darker, grimier areas to show through) and we were ready to put on the final stickers.

From the original laser cut plans we made a sticker sheet using our Craft Robo vinyl cutter

(the original stickers were designed and dry-fitted before the model was complete and spray painted but even at this early stage we decided they didn't quite look right)

While they looked fine onscreen, our original sticker designs made the overall ship too dark - it looked a muddy grey, instead of a battle-scarred white. So we left Paint Shop Pro alone and got rid of all our "spaceship texture" images and drew some panels and the paintjob as vectors in Inkscape.

(the subtle gradients and different levels of grey were removed and everything replaced with harsh, solid block colours, black lines on white and so on)

The end result was a pattern that looked a bit more "cartoon-y" but actually fitted in with the Lego characters much better than the original pattern designs.

Now if only there was somewhere we could conceal a small lipo battery and a charging circuit, we could cover the thing with tiny LEDs and maybe even add in a sound module......

xwing2 by chris_holden2495 on Scribd

xwing3 by chris_holden2495 on Scribd

Plans for laser cutting 2mm mdf
Plans by breakfastsandwich, stickers by Chris

Instructions by breakfastsandwich from Thingiverse

Wednesday, 8 February 2017

Google, can we have our internet back please?

Ok, it's not just Google. It's Amazon and Microsoft and Facebook and eBay. They're all pretty much as bad as each other. But Google are terrible for it.

Cross-domain scripting allows adverts from different sites to be placed inline, in a webpage, as if it were part of the original content. In the dark ages, we used to do something similar in IE, using iframes. Except it wasn't adverts - but the idea was the same; drag some content from another server and make it appear as if it's part of the original document.

At home I have a VirginMedia 100Mbs/sec connection.
It's pretty whizzy. And even allowing for relatively high contention ratio, I average around 70Mbs/sec. So it's not the connection. But when I recently tried to look for floor tiles on eBay (the exterior cladding on the bungalow is coming to and end so we're looking to putting a fancy skirt around the bottom) I kept getting error messages like this:

And having to wait 10-15 seconds, staring at a blank screen (the Chrome browser would go entire white, filling the screen all except for a "not responding" header in the title bar) between page loads. That is, when the page did eventually load.

So Steve suggested PingDom to see what was going wrong.,, and more. All calls to Google-related domains that were slowing down the page load.

And this screen shot doesn't show everything - there were over 20 "screenfuls" of this shite - all just to get a single item up on the eBay website (not a page of 25 or so search results, but a single item).

And littered throughout the page load, there were loads of failed documents/scripts.

It wasn't all just from the same domain either (though, ironically, it's that returns the most failed script loads - painless Javascript error tracking? More like bloody tortuous!).

The internet used to be a wonderful, exciting, interesting place, full of fascinating user-generated content. Now it's a quagmire of adverts and cross-domain scripts that are slowing bringing everything to a grinding halt.

Can you please fix it Google?
And then tell Amazon, Facebook et al how you did it.

I feel like I keep investing in new hardware, a better and faster internet connection, improved networking - and yet web pages take longer to load now than they did five years ago. And back then I was moaning about how shit they were and slower than five years previous....

Saturday, 4 February 2017

Cladding the bungalow workshop

Rain stopped play on the bungalow for a few days.
That and a bad back.

It's done nothing but rain for about a week now. And when it didn't rain, it was cold and damp and drizzly. And sometimes freezing and foggy. Which basically means our OSB3 panels need time to dry out (or, at least, for the surface water to dry off them) because we don't want to go trapping a layer of moisture between the OSB3 walls and our outer-skin plastic layer. And just when it stopped raining, and the sun made even the briefest of appearances to help dry the wood, my back went twang and all building work had to stop anyway.

Normally I'm not one for uPVC. I don't really like the harsh, white look and the slightly-nasty, feels-a-bit-flimsy, plastic-y feel. But since moving into a house with uPVC double-glazing everywhere, one can't help but agree that it's good at the job it's designed to do - it keeps draughts out and generally helps keep the place nice and warm.

And given that I'd already bought and fitted uPVC windows and doors for the bungalow, and I was looking for long-term maintenance-free cladding, I decided that maybe instead of shunning white plastic, I should fully embrace it instead. So I clad the bungalow in white uPVC panels.

The hollow white uPVC cladding comes in tongue-and-groove fitting, is water-tight, light-weight and - according to the vendor - the hollow sections can help improve/increase insulation! I don't know anyone convinced by the last claim, but it's quite popular on all kinds of buildings.

We got hold of some 2.5m lengths, which are 300mm wide. We're fitting them vertically (most people fit them horizontally, but I don't want the bungalow to look like a big white beach hut - even if that is essentially what it is!). All but one exterior wall will be clad with this stuff.

The wall on the partition between us and the neighbour's garden will be clad in wood, so that - from the neighbour's side at least - it fits in with the continuing span of wooden fence panels. So before cladding that wall in wood, we made sure it was completely water-tight.

Which meant fixing some 1200 DPM plastic along the entire wall - so should the cladding fail, even if it's in a good few years time, our OSB3 walls should still be safe from getting damp and/or rotting.

Wherever we had a sheet of board running close to the ground, we made sure it was protected by plastic. Then, over the OSB3, we stuck the uPVC panels on. At first, we were going to cover the entire board in plastic (as we did with the partition wall) but in the end decided that - because the uPVC is entirely water-tight - we'd be better off gluing and screwing the panels straight onto the boards. We used GripFill which has great grabbing qualities, and "hidden nails" to fix the panels (pinning each panel through the tongue, which is then hidden by the next overlapping grooved panel).

So we're pretty water-tight now.
The roof still needs some top felt, but that's as much about aesthetics as anything at this stage - with the plastic layer on at the minute, it's more than weatherproof; there are just a few scruffy edges to tidy up, and then ensure every join has a generous bead of silicon to keep the driving rain out, and it's time to get onto the fun stuff and move in!