New plan. Build a 3D printer. Simple.

As a redux of a plan I had in May, I'm now back on track with building a 3D printer. Spurred on by the release of MakerBot's awesome Replicator 2, it was either saving up and waiting until later next year, or hacking my own together now. Being impatient, the latter seemed appropriate.

Part of my logic is that I can quickly solve problems and technical issues with projects I have outstanding, by virtue of custom-making the parts I need and hopefully producing a better finish all round.

It also means I can quietly add to my stack of projects, but claim they're just sample print pieces when they fail or languish.

I also joined DEMU, a great resource for information (and detailed technical data) on diesel and electric traction, with a great deal of information on the on-track plant equipment I find myself drawn to (probably being bright yellow and a definite appearance of function over form).

I'd already heard of DEMU, but seeing them at the Warley show on Saturday and some amazing samples of printed parts (a pair of incredibly-massively-amazingly EMU detailed bogies) was just the shove I needed to join. I plan to make good use of their drawings for accurate modelling and printing of vehicles I've been trying to find desperately.

I've started sourcing parts for the printer, so it's probably time to start writing up the build in more detail. Even at this stage, there seems to be a whole range of technical issues to contend with before I even get hands on with building it.

I'm not sure how a 3D printer will solve my problems, but I just know it will...

To quote the Underpants Gnomes;
1. Underpants
2. ?
3. Profit

UX - More Than Fluff

My day-to-day work tends to get split three ways between information science, information technology and control technology. But the one underlying thing that's common to all and massively neglected across all, is good User Experience or "UX" design.

Too often developers excuse horrific processes and user experiences to "getting things done," or commonly the lack of a user interface design is excused with a weak contrast of consumer and industrial - after all, you only design an interface for flashy consumer gimmicky software and instead you should dump your industrial and business interfaces on users from a-high (akin to a pigeon shitting on your shoulder).

Most of our control work is fixed within the SCADA and networking of plant systems, so more often than not, we're involved with designing interfaces that control large motors, pneumatic actuators and quite often high pressure steam. And yet the portfolio of products designed for this industry isn't frankly good enough to automate a kettle. As a result, we've had to work outside the box and draw from our years of experience building enterprise-grade systems (both hardware and software), to distill what's expected at the high end of IT and deliver it to the field (quite literally).

And yet it's a struggle to convince people that a rainbow colour screen with randomly placed information, weird animations that are linked to unrelated attributes and all running on a crapped out consumer Windoze PC is not the high of industrial automation.

It does frustrate me that more time and effort is put into the graphics and displays seen on films, then are ever put into the real-life counterparts. For what it's worth, we're trying to change this and introduce a level of user experience that matches the serious nature and importance of the systems involved.

For now, I'll leave you with these first class UX/UI designers:

• Mark Coleran
• Jayse Hansen

Rant over.

Winter, the Project Motivator

Now that winter is slowly and cruelly creeping upon us, my lackadaisical project efforts have started to give way to a bit of focus. Over the next few weeks, there should hopefully be some big progress (and write-ups) on my projects, that include:

- RC Platform (aka UAV/Rover)
- RC Hovercraft Rebuild
- RC Boat Rebuild (set back slightly due to new hull damage)
- 28mm Model Building/Painting
- 4mm Plastic & Card Models (1/76th aka OO)
- Train Control System (LCB)
- Train Control Panel (DCC/Traction)
- 4mm Layout (1/76th aka OO)

Plus a big sprinkling of vac-forming, CAD work, panel building, Arduino hackery and lots more fun stuff. Oh and I'll also be lusting after 3D printers and CNC laser cutters. And robots.

Stay tuned.

RC Dual-Motor Control

The mission; to develop an Arduino based PWM mixer that can control dual-motor powered vehicles.

Having bought two RC vehicles that rely upon dual-motor control, in the process of stripping out their original low-spec electronics, I was in desperate need for a mixer to take the steering and throttle channel inputs and mix them into left and right motor outputs.

Having searched for a solution, the closest I could find was a ludicrously expensive RC tank ESC, circa £300. So, with an Arduino to hand and a couple of servos, I started developing a simple mixing routine.

The input signals were PWM, or Pulse Width Modulated - a simple way of transmitting an analogue signal using digital pulses - supplied by the steering and throttle channels of the receiver. The corresponding outputs would also had to be PWM, in order to drive the ESC that the left and right motors are driven by.

The outputs are the easy part with help from the Arduino servo library. Most people have driven a servo from their Arduino, it's a nice simple piece of coding, no circuitry, just plug-in and go. But reading PWM turned out to be a bigger problem to tackle then I initially thought. The big mistake was assuming I could read PWM signals easily with the Arduino.

A couple of solutions are floating round, I think I found some on StackOverflow and others on robotics forums, where people were trying to integrate RC receivers with Arduino as a simple alternative to ZigBee.

I even hoped to use that same approach on other projects myself, so was set on getting it to work. In fact, it all sort of started coming together nicely - the RX is even powered off the Arduino's 5V bus, so it keeps things quite nice and simple.

But the code just keeps getting more complex.

In short, it's possible, but a lot of code is needed, and the Arduino can't do much else. From all accounts from others working on similar code, it struggles to read and write two PWM signals. Bugger. I might come back to it sometime, but it's not a nice reliable design at present.

So back to the drawing board.

The final breakthrough came in the form of a £4 electronic mixer. Better known as a V-Tail Mixer, these are designed for simple fixed wing aircraft, that utilise a pair of servos to operate bother rudder and aileron - the mixer takes the values of both and mixes them proportionally. Bingo. Perhaps this is the RC communities biggest secret. Perhaps I've found a genius alternative use of the mixer. Perhaps everybody does this. Who knows? I found jack shit on my travels, so I've come to the conclusion that I made a ground-breaking discovery.

The mixer is perfect - it takes the input values and passes them through mixed. It doesn't do anything else to the signal, so the resulting output seems to work with everything including uni- and bi-directional ESC. And they're £4. Tiny bit cheaper than an Arduino. And less effort.

Perfect. Let's rewind this. The perfect solution, that would fit virtually every use of dual-motor powered vehicles, whether they be boats, tanks, hovercraft - whatever. It costs £4. And yet, it's being sold and advertised solely for people with a V-Tail whose radio transmitter lacks an onboard V-Tail mixer setting. Great.

But all is not lost... In my struggle to find a solution I found the OpenServo project. Quite genius really. Simply, the project's main hardware development is an I2C based controller board, with virtually the same footprint as the regular PWM controllers found in servos. There's a lot in such a small package - including temperature monitoring, advanced programming, braking and a massive voltage range.

Coupled to the I2C bus on the Arduino, I have high hopes of advanced control for robotics (and anything else I can wedge it into). The I2C bus seems to be more and more popular, with it being used for a wide range of applications these days. So, not really of use in driving speed controllers for this mini-project, but definitely of interest for the future...

Productive Fortnight

Having a 4-day weekend is a definite recipe for hobby productivity...

Over the Jubilee weekend/week I managed to push forward a number of projects, including; the OO scale card modelling, the RC dual-motor controller and a couple of new projects.

One of the new projects is Arduino based and makes use of the output channels to control scale lighting on my forthcoming OO layout. The idea is to simulate a day in scale speed and loop through a list of lighting circuits which have start/stop times - as the time is reached the lighting circuit is either faded up (PWM outputs) or flickered on (in the style of fluorescent street lights). I want to avoid building too many circuits (555 timer etc), as the programmable nature of the system gives me the flexibility to tweak and change the lighting as desired (without having to fix on/off times etc with resistors/capacitors).

The main code function is a loop, so with a scaled pause and incremental counter, I can approximate a 24 hour day in whatever time base I want. I could use a potentiometer to dial-in a scale, or I could fix the scale in code. I'll define a number of lighting types, which will define either an analogue/PWM control or a digital control of the circuit - the PWM will allow for fading and the digital for simulating fluorescent and regular tungsten. I can also go ape-shit on the lighting with backlit billboards, building signage etc and funky lighting effects.

My plan is to also use an interrupt channel in order to reset or tweak the playback (perhaps skip an hour etc), that'll enable the loop to be broken and the interrupt code to be executed before the loop resumes.

No code written, but lots of notes and ideas on scrappy bits of paper. When I get a few minutes I'll start sketching out the code. The main issue is devising a template way of driving the lights - I'm thinking of using LEDs for most things, so each channel will need to power a handful of mini-circuits.

This started off the back of me wanting to simulate welding flicker - something I still want to model and may perhaps execute with this approach (probably a little overkill for an Arduino however). Another project on the list; just what I need!

The card models have come a long way - I've virtually finished the low-relief workshop and moved straight into building the concrete bridge. With that finished (sans a few bits that need to be assembled when I know the exact layout of the bridge) I moved onto two new ones; the inspection pit and the small goods store. I've modified both slightly, as I wanted two inspection pits out of the one kit and the small goods store didn't work too well with the type of card I'm using, so some extra glue joints and cover caps are needed there.

The dual-motor controller is an entirely different matter and deserves it's own post...

On a side-note, I did get to see the Queen.

First Vacuum Form

Well then, after a complete strip-down and check over of the new vacuum former, I clamped down, heated up, vacuumed and released.

Rather than waste a tonne of new sheet, I reused the first sheet - trying to figure out the heat settings, the timings and the vacuum capacity. I did get distracted at the end by a delivery and slightly burnt the sheet - though it did form better. The sheet was getting a bit fried anyway, so no loss. Gave it a nice texture!

I've got a lot of research into plastics and to figure out the timings with this former, but it's looking to be great fun already. I forgot how badly things start to smell and the strange plastic tastes you get in the mouth when vac forming... Ahhh, how we do like plastic.

Any suggestions for things I can make? I've got too many ideas, so I'm hoping to narrow them down with some horrific suggestions from others. A T-Rex easter egg mould is currently in lead!

Another Decade...

Well, if I've got to grow older, then I deserve cool stuff to make up for it.

So, roll on my newly acquired C R Clarke 1210 vacuum former. Photos to follow, but for the uninitiated, it's a plastic former that uses a combination of heating elements and a vacuum pump to form plastic over metal/wood/plaster/resin formers.

I've made some modifications already to the vacformer, the most major being the replacement of the rear rubber feet with steel slotted rail (actually DIN rail) to better bare the weight of the former across the rear structure (and offer a great way of mounting it to a workbench).

I've been mentally forming a list of things I plan to make on my new toy professional work apparatus, including hovercrafts, boats, chocolate moulds, ice trays and much more. Well, so much more that I'm forced to keep a list with me, adding lots at random moments of the day.

I've built plenty of formers in the past and have lots of experience with chipping plastic off of complex formers, spreading wax and other shit (recommended by clueless "experts") over the formers, burning plastic, cracking plastic and occasionally, making something really nice. My most successful former (a fairly complex wooden one, made of multiple laminations of wood) is still in heavy use in an engineering lab some 14-15 years later.

Anyway, I can't wait to start building formers - can't beat a present that keeps on giving...