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JG's TinDog build

Started by jaguwa68, Mar 22, 2011, 07:27 am

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jaguwa68

Mar 22, 2011, 07:27 am Last Edit: Jul 10, 2011, 04:43 pm by Scarfwearer
I originally built my very first K9 back in the 80's, which I'd based on the plans available in the Doctor Who Technical Manual. These plans were sadly flawed in accuracy, especially for the shape of the head, though I didn't know this at the time. The head was a lot fatter and the snout quite short in comparison to the TV version, which I later found out (via a letter from Matt Irvine) had been adjusted at the last minute on the working model only to suit an internal mechanism problem. This K9 never lived long, mainly because I was a teenager living at home with my parents at the time, and with the house being quite small, poor K9 Mk1 just kept getting in the way. So come November 5th he met his demise as that years novelty guy  :o.

It wasn't for another 20 years, and with news that K9 was not only returning to the new series, but that it was being filmed in my daughters school a mere ½ mile away that I felt inspired to bring him back to life in my house. This time though I would take my dimensions from photographs, and model everything up in 3D CAD first. My aim was that not only would he be dimensionally accurate, but also as fully functional as my capabilities would allow.

K9_CAD1.jpg K9_CAD2.jpg

So, using a side elevation photograph of the Matt Irvine prop as a starting point, I began modelling him up in 3D CAD, starting with the external casing. Parallel to this, I started collecting together K9'y parts I could potentially use as materials; an old corrupted pc was dismantled to eventually serve as decoration circuitry; a defunct washing machine was taken to bits so that I could use the metal from the casing and the various oddly shaped injection mouldings from the inside could be adapted to use as mountings for the internal LED arrays. I also ended up with more hoses, broken electronic components and coloured tubing than I will need for making the interior look "alien tech" when the side panel is opened.

Once I'd progressed far enough with the digital version, I started to build the casing. For the majority of the body and head I used hardboard, as it's easier to cut and shape. These were joined at the corners using wooden batons, steel mesh sheeting, wood glue and no-nails. I chose not to use nails, as I wanted a smooth exterior with no visible fixings. The side panel, K-9 logo and back control box were made from aluminium sheeting, folded into shape around tubes and work bench corners.
Bonding the head together presented a bit of a challenge due to the compound curvature, so I needed to wrap plenty of masking tape around the snout while to glue dried. The nose is a piece of an old vacuum cleaner tube, cut to size, bonded and filled.

13-K9_081006.jpg 16-K9_Newport_081006.jpg

12-K9_081006.jpg 17-K9_081006.jpg

The interior head mechanism for allowing the antenna to contra-rotate was quite challenging, as the centre lines for the antenna are not parallel. So I dismantled an old DVD ejection unit from a broken DVD player, and cobbled together the gears in ratio. I linked these to the antenna rods using UV joints and then linked the main gear to another rod connected to a servo.

K9_CAD3.jpg K9_CAD4.jpg 12-K9_191206.jpg

The eye probe is simply an aerial, though this currently only manually deploys. The nose laser is a small self ejecting piston, which travels down two tracks on the modified remains of the DVD eject unit to allow it to extend further. Again, this is currently manually deployed, though I have an idea how a further servo could be linked to this for RC operation later. A small LED array has been fitted behind the red eye strips, which are back-painted 6mm Perspex. As a small touch, I set the lens from the DVD laser into the end of the nose, the tip of which is the ridged cap from a marker pen.

3-K9_051008.jpg 4-K9_051008.jpg

The interior structure is constructed from steel box section donated by a neighbour. Due to the interior angle, this proved to be quite complicated, not to mention heavy. Originally I intended to use one large wheel for steering and two smaller ones for stability. Due to packaging restraints, I have now gone for two small scooters braced across the framework.
For the base of the tail I took an old joystick apart and adapted the base of it so that it would fit inside the casing. Three varying sizes of ally tubing make up the tail, ending in a shower curtain ring. I wanted to use a larger end ring in the hope that it would be easier to see, for aesthetics as well as avoiding getting it kicked off by accident. So the result is that the tail manually flexes about 30 degrees in all directions, but the large spring which was part of the joystick is enough to return and support the tail to it's centre position.

And this is as far as I've got. My intention is to rebuild the framework using aluminium to reduce the weight, but family issues, house moves and a TARDIS build have mean that K9 has been on hold for several years now. I have yet to work out a steering mechanism and how this can be linked to the remaining servos in the RC pack that I bought. This summer however should allow some time for a revisitation...

K9_5.jpg K9_6.jpg

1-K9_051008.jpg K9_3.jpg K9_4.jpg1-Argus_010411_reduced.jpg

philipw

He sure looks great.  :)

lswl

That is an exellent K9! Way to go there!

acid

That is fantastic. Is there anyway you could upload other plans you used while making your K9? I'd really like to make one myself and am currently gathering a lot of reference pictures and plans from everywhere...

jaguwa68

Sure. In my eagerness to start, I took the dimensions off the 3D model, so I didn't actually get round to creating an engineering drawing at the time. Having said that, I'm in the process of redesigning the interior structure to take out some weight, so it won't take long to knock out some standard views and sections. I'll post later this week  ;)

jaguwa68

May 14, 2011, 10:02 am #5 Last Edit: May 16, 2011, 05:43 am by jaguwa68
The dimensions below I arrived at through a combination of those printed in the Doctor Who Technical Manual (1983), photographic tracings and tips given in an old letter I received 20 years ago from Matt Irvine. Hope this helps. Shout if you need anything else.

Rgrds John

K-9 draw sheet1.jpg K-9 draw sheet2.jpg

lswl


Scarfwearer

So where did you get the buttons on the back of your K9? I seem to recall that they may have been some of the actual Season 14 console buttons that I'm trying to replicate. The story goes that Mat Irvine junked that console, but saved the electrics for future projects... then K9 appears shortly after with very similar buttons...

Crispin

meantimebob

you want something like this:
http://products.eao.com/index.php?IdTreeGroup=64&IdProduct=49084

but to save money, you could try ordering just a load of the lenses, unless you really want them to be buttons that work. You could easily make them light up at the back. I don't think the original version of K9 actually had buttons, they were just the lenses.

meantimebob

in fact here they are, dunno how much they are but I don't think they'd be much

http://products.eao.com/index.php?IdTreeGroup=64&IdProduct=52563

cyberstephen

Hi Crispin,

you can get the buttons and lenses from www.cpc.farnell.com; they are a UK-based company selling all manner of electrical components. Because my K.9 is a non-practical prop, I only needed to buy the lenses but they were very cheap at approx 25p each. A handling order of about £8 or so was added on so it's best to make sure you order everything you need in one go.

As far as I can see, the buttons are an exact replica of the original K.9 control panel, but be warned, this company will send you brochure after brochure through the post.
Stephen

rasilon1

Oh the power of 3D CAD,  :) you can build it all in 3D before you even make a cut  :)
This is my first step in designing or building anything what package are you using ?.
The inventiveness of the members on this website and others to reproduce props from Who is just brilliant, I am sure that the BBC love
websites like this as it would give them handed redesigned work for free, that would normally cost them big time.
Excellent Design work and skill in using electrical mechanical item. To Job.  ;)

jaguwa68

I'm afraid I can't offer much advice on how to get hold of the switches, as my Dad got them from work, which was the electronics division of GKN in Somerset. But he retired 6 years ago now, and I've had them on the shelf for years knowing that one day they would be put to good use. Eight are just lights, but three are actual illuminating switches, which will eventually operate the eye lights and internal rope lighting, once I get round to it again....

Scarfwearer

Well I've ordered 100 of the lenses from CPC - can't quite stretch to getting 100 switches... :o

Thanks people,
Crispin

cyberstephen

Good job. Better gaffertape your letterbox soon though(!)
Stephen