Projection Ideas

Attaching the projector to the filming mechanism in place of the camera

Achieving a way of rotating the image around the room - the problem with rotating a projector is that the wires will get twisted up. The images below show an idea of using a mirror situated at 45 degrees to the projector lens. The image is projected into the mirror and thus reflected on to the wall, therefore through rotating the mirror on its axis the image is projected around the room. There would also be a point where the image is projected through a piece of red perspex and therefore the image would have a red glow - relating back to the red sector in the lantern room.

I tested this method and although it did work, the image itself rotates as it is rotated around the room - an interesting effect but not quite sure its what I am trying to achieve.

Further research has been into using a portable projector which has a battery source built into it and therefore doesn't need to be plugged into the mains which eliminates the problem of the wires. Alternatively there is the option to use a rotating display unit with a slip ring.

Rotating Movements of the Filming Mechanism in Plan

The filming mechanism consists of two rotating elements which circle at different rates, in order to alter the camera position from the outside of the spiral in plan to a central radial position. In deciding the ratio of these two rotating elements, I shall relate it to the lighthouse I am filming within and the Needles lighthouse across the water filmed through the windows of Hurst Point Lighthouse. Each of these lighthouses have different light characteristics:

HURST POINT LIGHTHOUSE: 4 FLASHES EVERY 15 SECONDS

(LIGHT 1 SECOND, ECLIPSE 1 SECOND, LIGHT 1 SECOND, ECLIPSE 1 SECOND, LIGHT 1 SECOND, ECLIPSE 1 SECOND, LIGHT 1 SECOND, ECLIPSE 8 SECONDS)

NEEDLES LIGHTHOUSE: 2 FLASHES EVERY 20 SECONDS

(LIGHT 14 SECONDS, ECLIPSE 2 SECONDS, LIGHT 2 SECONDS, ECLIPSE 2 SECONDS)

Therefore the two pulleys shall be in the ratio of 3 : 4 derived from the ratio of their light characteristic cycles of 15 seconds : 20 seconds)

Filming Device: Quick mock-up model

In order to test my idea I put together a quick sketch model of the workings of the filming device from various scrap pieces I found around the workshop and at home. The model is mostly made from aluminium due to the light weight properties of the material. A cotton reel and homemade foam board wheel (of different sizes) are used as the pulleys, which are connected by a rubber band. A large single ratio motor gearbox is run off a 9V battery source, which puts the device into action. The camera would be affixed to the underside of the lower aluminium element at one end. The device would be suspended from the upper aluminium element.

Mock up model of the Filming Device

The film below shows the device in action. I have marked the location of the camera with a pink spot. If you watch the movements of this spot, it is noticeable that due to the two aluminium elements rotating at different speeds, the location of the pink spot / camera varies its location from being directly underneath the motor to being at the outermost reach from the centre, whilst in a spiral motion. Therefore giving a zooming effect of a camera whilst spiralling.

The mock up model in action

Watching the device in action it achieves the movements I am trying to captured. It is noticeable that the larger pulley wheel starts to tilt as the band slips up the shaft. Therefore it is going to be essential to make sure these elements remain horizontal. The speed of the motor is also too fast, this is noticeable in the camera footage captured below. I have since acquired a speed regulator. The speed could also be reduced if the size of the pulleys were increased. Counterweighting also needs to be addressed.

Footage captured by camera

Filming Device: Working Drawings

Drawings for discussions with Brammer tomorrow...

Movement of the mechanism

Filming mechanism possible workings???

Filming mechanism plan

Filming Device: Complex Rotational Movement

The final filming mechanism which I have decided upon involves a series of complex rotating movements. The engineering of this device is going to be a challenge, but I am adamant to put it into action.

The design involves three triangular shaped elements (see drawing below), the top element is attached to a number of wires which are unwound from a pulley above (cantilevered from the stair). As the wires are unwound, the device descends through the space. Attached to this top element is another triangular shaped element below which rotates, and attached to this element is another element which also rotates at a different speed. A camera is attached to this bottom element and thus films the space as it descend along a random spiralling path around the void. There is a possibility to include a fixture which allows the camera to be positioned at different tilted angles, ie. so that the camera could be positioned looking upwards, downwards or horizontally.

The rotating/spiralling movements are in keeping with the spiral staircase and the idea of two rotating elements, which move at different speeds relates to the two lighthouses - Hurst Point and the Needles - each has a different light characteristic and in many lighthouses this is caused by the lenses rotating at different speeds. These two complex rotations combined allow the viewer (of the resulting film) to be transported down the spiralling staircase along a random path which thus zooms into and away from the staircase.

3D view

Plan of mechanism rotations (& camera field of view)

Elevation of mechanism

These complex movements are a tricky engineering challenge to solve, there are four key areas - balance, smooth rotation, two rotational speeds and rotational power.

- Balance

The weighting and rotation of the elements means that each element will need to be counterweighted to ensure balance across its three points. ie. the lowest element will need to be counterweighted at the other two points to balance for the weight of the camera. The middle element then needs to be counterweighted at the other two points to balance for the weight of the lowest element. Therefore there is a tricky task in ensuring that the device is kept as light as possible.

- Smooth Rotation

The elements need to rotate smoothly to ensure that the camera footage captured is not susceptible to bumps and jerkiness. This should be achieved through the use of bearings at each of the rotational points. Ideally bearings would be fixed below and above the triangular element. The trouble here is finding lightweight bearings, as these bearings often have cast iron casing.

- Two Rotational Speeds & Rotational Power

Each of the rotating triangular elements need to rotate at different speeds, this could possibly be achieved by the use of two different wheels of different sizes, with a belt linking them. They could both be powered by a single motor which could be mounted on the stable top element. This could if possible be battery powered, but if not it could be mains powered.

Filming mechanism detail elevation

Filming mechanism plan with belt detail

I am starting to make the device to try to solve all the possible problems and understand its movement and imposing forces. If I do manage to achieve this, below is a sketch of a possible way of installing the device, with a battery powered projector mounted on the duplicated device. Referring again to the two lighthouses across the water from each other. Between the camera and projector is a red sector which refers to the red sector within a lantern room of a lighthouse - notifying ships of danger. This is the in between point of the two devices, where camera meets projector and the feedback loop would get confused. In this installation I would however project the film captured within the lighthouse (if I am unable to film inside the lighthouse I would film inside the fire exit stairwell previously used).

Installation (camera on left, projector on right)