Lights at last

Lights At Last

Never one to finish anything when there's something else to distract me, a recent burst of activity has seem some progress on several fronts including the lights.

The pictures below show the isolation circuit board which provides optical isolation between the Arduino UNO connected to my laptop and the lights themselves which are connected to their own 48v/12v/5v power supply.
This plugs into the Arduino like a standard shield.

The above power supplies, Arduino and isolator card along with a powered USB hub and the additional 24v power supply for the motion control rig are all contained in a single 'master' unit. This means just one mains socket and one USB cable from the laptop are required to operate the lights and motion control rig from DragonFrame.

Lights isolator board

The four headers connect to 7-pin DIN sockets on the front of the master unit which the lights themselves are plugged into.
Below are some images of the finished prototype lamp.



High Frequency PWM Dimmable LED Lamp

High Frequency PWM Dimmable LED Lamp

 The whole point of this exercise is to create an inexpensive stage luminaire that suits the small animations stages found in various sheds and spare bedrooms around the world. The use of a 40 Watt LED element results in adequate brightness with virtually no waste heat and the use of high frequency (4kHz at the moment) PWM control means no resulting flicker when the lamp is dimmed if the camera exposure period is relatively long (say, 1/100 seconds or more).

The initial dimming test has shown a small amount of flicker in the resulting video (yes, the aperture was used wide open). Further tests are required to confirm the source and, fingers crossed, eradicate it.

The 'Other' Puppet(s)

Whilst plasticine Jock is the narrator of the tale I wanted the other characters, who will act out parts of the story, to be cardboard cut-outs.
A few experiments showed that cardboard would not stand up on it's own and that using foam board to make things more rigid produced a usable but not entirely satisfactory puppet.

Christie then told me about 'magnetic paper'. This is designed for you to make your own fridge magnets, but we decided to experiment with it to make an articulated cut-out puppet which would stick to a standard magnetic white board. This worked very well in practice, there being enough grip to keep the puppet in place and allow one part to be moved without every other part losing position but not enough to make movement difficult.

The puppet design was worked out on paper, hand coloured then scanned into the PC. The design was then tuned and colours adjusted in Photoshop Elements before being cut out and articulated with hidden cotton joints.
The image below shows the test shoot in progress with the Sony DSLR suspended from a tripod and the laptop with DragonFrame nearby.

 

 

  The new plan is to paint the whiteboard green and chroma-key the puppet into the background. This allows us to adjust the size of the final image and so make the puppet at a convenient size to handle rather than tiny enough to appear to be at a distance in the 'Scottish Hills' set.

 

The test video, with the puppet supposedly creeping quietly, is below.

Never one to do things the easy way, I want to use lighting controlled by DragonFrame to add to the overall look of this piece. Paying serious money for large, hot, tungsten based stage lighting is not an option, either from the financial or where-on-Earth-are-we-going-to-store-these(?) points of view. Available LED lights are also large and expensive as well as likely to induce serious flicker when faded.

So, I've designed a reasonably high brightness, high frequency PWM (Pulse Width Modulation), small, inexpensive LED lighting system specifically intended for use on table-top animation sets. Power demand is low, heat output is minimal, flicker when dimmed is eliminated, overhead rigging for mounting the lights can be lightweight and easy to pack away. You can even change reflectors to alter the angle of the beam!

Here's the prototype lamp itself:

The power supply is a 48v switch-mode unit. A small circuit board on the far end of the heatsink provides a constant-current source for the LED (the correct way to maintain a steady light output) and can turn the lamp on and off at high frequency under PWM control from an Arduino controller.
The final design may require a fan on the heatsink and will have suitable hanging brackets mounted onto the slotted cooling fins you can see in the picture. Unfortunately control from DragonFrame will require the purchase of a DMX-2 interface box (the single most expensive component in the whole rig) and DMX decoding software on the Arduino controller.
I'm currently waiting for some high speed opto-isolators to arrive from RS so that I can see whether the lamp will fade properly at a PWM frequency of more than 10kHz. I recon this speed should avoid any flicker at any of the exposure settings expected in the real world. We shall see!

Jock's head has used up a fair amount of time lately. This being my first experience of puppet making, sculpting etc. I'm learning from my mistakes. The picture below shows the current iteration. The eyes are not right, much too much black, and will need to be cut out and reworked. It's a real joy living here on the edge of nowhere, but the lack of shops that sell things as simple as Humbrol enamel paints can be a pain. I'll be trying nail varnish next.

I really must try animating Jock's mouth. His performance is going to be an important part of the success of this production but I keep putting off the hard bits, hence the recent work on the lights!

Progress continues on outfitting Jock. He now has socks, a kilt and most of his DJ in place.
I want as much of him as possible to be plasticine. It didn't take long to decide this should not include the kilt!

Keeping the  plasticine clean is as big a problem as everybody says it is! The socks and shirtfront will require some careful cleaning before shooting begins.


How big should the eyes be? How do you fit eyes into a plasticine head?

Good questions to which I now have the answers thanks to the charming model below:

Whilst the smaller eye is closer to reality, puppet eyes always seem to look better when grossly enlarged, so larger it is. Making the eyes movable was achieved simply by coating them in Vaseline before pushing them into the plasticine socket. Even after several days the eyes will move soothly with the aid of a pin pushed into the pupil hole.

Jock's Armature 1

The key character in the poem is Jock McFee. In this film he will be 250cm tall and made largely of plasticine (the Wallace and Gromit influence). This puppet requires a moving 'skeleton' or 'armature' to make him movable but able to stay in whatever pose he's put into.

The core of the armature is a frame made of twisted aluminium wire with epoxy putty used as 'bones' between the bendy wire joints.
His chest is made from balsa wood which supports square tubes into which the arms and head will fit.
I've deliberately used this sectioned construction as it allows me to change or remake the arms and head easily.

Here you can see the square tubes for the arms and neck. Smaller tubes are a close fit into these. Square tubes are used instead of round to make sure the parts can be put back in exactly the same place if repairs are needed during the animation.

 

In the beginning

The Hunter of Dunoon

This blog will follow the making of an animated film called 'The Hunter of Dunoon'.  The story is taken from the soundtrack which is a recording of my late father, Tim Norfolk, reading his own poem of the same title.

This is my first attempt at animation and will be a serious learning process for me. No doubt this blog will chronicle many mistakes and pitfalls along the way to the final result. It is also my first attempt at writing a blog so we'll see how that pans out as well.

Brief Encounter

This short animation started out as a test of my home built motion control rig and it's control from Dragonframe animation software (more on this later).
It ended up as a full blown love story! My first animated film.

Click here to see 'Brief Encounter' at Vimeo

First Sculpture

I had though I'd need someone else to sculpt the heads of the puppets but thought I'd have a go myself first. After finding a really good on-line tutorial  at the 'Doll Maker's Dream' website describing how to make doll's heads from clay I set about following the instructions using Plasticine.


I was amazed at how easily the following chap fell out of the clay!

Not the most handsome face you'll ever see but good enough to convince me that a bit more practice might be well worth the effort.