FabLab Academy 2012
This section is designed to update and complete the documentation for
my final project and reflect on the course...
When we were directed to plan our final project, in the first week, I
decided to produce an old style stage ventriloquist dummy. My original
intention was to make a manually controlled head unit and seperate
body. Throughout the course, as new units were taught, I modified
and updated the design. It became clear that with the new possibilities
introduced by the electronics and programming sections that my final
design must include electronic control.
A major restriction in design was size. I experimented with various
methods of trying to squeeze motors, pushrods etc into such a small
space, and still retain functionality. I used Rhino to create the block
head out of slices - then removed sections for the eye unit and mouth
unit. The mouth would be created using the slice method, but the eye
unit was far more complex.
The design of the eye unit was perfectly suited for 3D printing. I
by printing small prototype eyes to determine the minimum gap size -
2mm was too small - 5mm gap produced a good fit and smooth rotation. It
took two days to dissolve the support material - so desiging a less
bulky eye was required.
To prove the control system, and assist in the design process, I
manufactured a series of test rigs from easily obtained items (25mm
wooden beads for eyes - meccano for the frame - springs, rods and
screws from a local craft shop).
The first system used servo motors for eye and mouth movements. The
control was programmed using an Arduino Mega. A nintendo Wii nunchuck
acted as the hand control. It was intended to replace all this with a
servo board, and the hand control would use the most appropriate input
method (hello button/hello load...) But for now this will remain on the
list for future improvements.
Although the movement produced by servos was good, the noise they
produced was not.
The next rig used stepper motors - these were considerably quieter, the
control they offered was good but their size, and weight offset these
Each test unit made could also be operated manually.
The task now was to create a final design which would use as many
FabLab operations as possible.
In order to complete this project in time I've had to make some
A combination of machine availability, design time required and a flood
in the FabLab means that a more basic ventriloquist dummy will be made.
The full original specification will be produced as time and machine
availabilty permits, in the future.
The design elements of this project posed quite a challenge. I had
decided early on in the course to use Rhino for 3D design. I had not
previously used this software, and for the duration of the course, a
free beta version of the software was available for the mac. However
this was a stripped down version with most of the plugins unavailable.
Deciding on the best method to use for the manufacture of the head was
tricky. Traditionally the head is carved from a block of wood or cast
in sections from a mould. I considered milling a mould using the
modella or the shopbot, but this was too complex and time consuming -
maybe for the future...
I also investigated using Autodesk's '123D Make'. This software had
just been released and could slice a 3D model into sections. I
conducted trials with cardboard and plyboard, using the Epilogue Laser
cutter, but the structures were too flimsy.
I eventually decided to construct a similar model using Rhino. This
would be a basic block head shape which could be cut using the shopbot.
This gave a result which was more like the carved block method.
The body and arms were fairly straight forward. A frame for the hips
and shoulders was cut using the Shopbot and the structure was finished
using dowels and heavy duty muslin. This material was also used for the
limbs. The material was cut to size using the Laser cutter and stitched
using the Sewing Machine.
Electronic control was required early on to prove the eye and mouth
mechanisms. Here the Arduino made life easier. Routines were written to
control both servo motors and stepper motors. Control was provided by a
Nintendo Wii nunchuck. This required some investigation and
experimentation to implement, but proved to be a slick way to
interface. If time had permitted this contol would have been
manufactured using modified hello.servo and hello.input boards.
To overcome the problem of giving the dummy it'a own individual
character, I decided to lasercut and etch a selection of faces which
would fit onto the dummy head. Cut-outs for the eyes and mouth would
reveal the working eyes and enable the mouth to move. As an interim
measure I used cardboard printouts.
The Fab Academy has been an amazing experience. I have found the range
of material covered and pace of the course quite a challenge. The list
of subjects for me to follow up and study in more depth has continually
grown. I have particularly found the electronics and programming
modules to be valuable. I now have a long list of potential projects to
Video of completed dummy in operation here.