User:Myk Streja/Spinning tunnel

Spinning tunnels—which are also known as vortex tunnels or rotating tunnels—are devices used at haunted attractions and amusement parks. When people walk through the center of a spinning tunnel they can experience vertigo and a loss of equilibrium as their brains receive conflicting signals from their bodies and senses. A prominent manufacturer of the attraction, GEP Productions, registered the trademark Vortex Tunnel®, and has subsequently defended the trademark vigorously.

The traditional version of the spinning tunnel consists of a tube made up of a series of rings which is typically up 10 feet high and up 20 feet long. The tunnel liner bears images or designs that create the illusion of movement while the tunnel is in motion.

Another type of vortex tunnel uses a stationary tube with LEDs or rope lighting imbedded in the walls which light up in patterns designed to mimic motion.

Laser vortex tunnels that can be contained in a domed enclosure are favored by the home haunting industry. Made from parts acquired a at local hardware or discount department store, the tunnels are built using LEDs, incandescent or flourescent lights, blacklights or lasers—or any combination thereof—paired up with a laser vortex. The laser vortex lighting system projects a rotating pattern onto the mist or fog provided by a fog machine, creating the illusion of a moving vortex.

Traversing the tunnel is a beam bridge, usually about 36 inches wide and about 15 inches high, which provides the pathway for visitors to pass through the attraction. Handrails securely fastened along the length of the bridge are necessary for the safety of the participants. Lighting for the tunnel can be mounted under the eaves of the bridge or beneath the handrails, and may consist of rotating colored lights, high-powered LED lights, laser lights or blacklight fixtures. In the case of the laser vortex tunnel, the lighting may be mounted on the floor. The bridges or walkways can be designed to tilt, wobble or vibrate as visitors proceed along the path, providing unstable footing and causing a further loss of balance.

For those tunnels not enclosed in buildings, there are various types of enclosures designed to protect the tunnel from the weather and vandals, and to keep visitors safe from contact with moving parts.

Background
Spinning tunnels depend upon creating sensory confusion between the kinesthetic system, the vestibular system and the visual system. The body's sense of the motion and the position of the limbs is provided by sensors in the joints, the semicircular canals within the inner ears provide sensory data for the head's position relative to the ground, and the eyes provide input concerning where the body is in relationship to its external environment. The spinning tunnel creates an optical illusion affecting the visual system that is in conflict with the other two sensory systems. Because vision is the most heavily relied upon of the human senses, the visual system overrides the other sensory systems and causes the brain to believe that the bridge is moving. This belief interferes with the sense of balance and induces dizziness and vertigo. Aristotle noted the effect while observing a waterfall, noticing that over time the water seemed to stop moving and the rocks protruding through the waterfall seemed to be moving upward. This phenomenon is now known as the waterfall illusion or motion aftereffect.

Rotating tunnels
The rotating tunnel consists of a cylinder made of large rings secured together by trusses, rods, or braces. Typically 8–10 feet in diameter and 10–20 feet in length, the rings of the cylinder ride on hard rubber tires, large pulleys or spoked rims (as found on a bicycle without the tire). One of the wheels is connected by a belt or chain to an AC motor which drives the cylinder at a rate of 4–10 revolutions per minute (rpm). Some varieties use a motor mounted above the tunnel. The tunnel is easily stopped as there is no direct connection between the motor and the tunnel. The tunnel is lined with fabric or plastic sheeting that has been painted or imprinted with various designs or images. When the tunnel is rotating, the designs or images create the illusion of movement counter to the rotation. Running through the tunnel is a suspended bridge, usually 28 to 36 inches wide and 8–16 inches high. At 36 inches wide, the bridge is wheelchair accessible. Handrails line the bridge to keep patrons from falling off the sides into the rotating tube, preventing injury to themselves or damage to the tunnel. Spinning tunnels can be purchased at commercial retailers at prices ranging from US$8,000 up to $35,000 for a trailer mounted system.

Construction and materials
The construction of the spinning or vortex tunnel is formed of several discrete components. There is the base or framework, the tunnel, the drive mechanism, the lighting system, and the bridge or walkway. These components can be made of nearly any material, such as plywood, or metals like aluminum or steel, or PVC piping, as long as the materials used can take the weight of the tunnel and the weight of the guests traversing the tunnel.

Framework
The base of the spinning tunnel holds the guide wheels that the tunnel rings rest and roll on. The drive motor for the tunnel that has the drive motor driving the guide wheels will also be installed on this framework. The tunnels that have a drive motor above the tunnel will have a vertical framework that is attached to the base. The guide wheels can be bicycle rims or pulleys which also hold the tunnel in place as it spins. Tunnels that use the hard rubber wheels will have an extra set of horizontal wheels at both ends, attached to the bridge, to keep the tunnel from wandering off the guide wheels. The bridge is also mounted to the base.

Tunnel
The tunnel is constructed of a series of two to eight rings, usually eight to ten feet in diameter to allow headroom for the people using the tunnel. The vertical rings are connected to horizontal braces forming a cylinder similar in shape to a large coffee can with the ends removed. The interior of the spinning tunnel is lined with fabric or plastic sheeting with secured to the rings and braces in whatever manner is expedient to the builder or designer of the tunnel. Velcro straps, duct tape, and staples are used in different constructions. The liner can be printed or decorated with images or abstract designs that draw the eye and further the optical illusion fostered by the rotating liner. The use of fluorescent inks or paint and black lighting can add to the enjoyment of the attraction by creating a spooky, darkly lit environment. Music or other sound effects help to mask the sound of the rotating tunnel and the operation of the drive motor.

Lighting systems
The lighting systems for the tunnel can consist of regular incandescent light bulbs or fluorescent lamps, colored lighting using filters, black lights, LEDs or laser lights. The lighting systems are attached to the bridge or the handrail to illuminate the fabric of the tunnel. Blacklights are most useful when there are fluorescent designs on the fabric of the tunnel. All of the different types of lighting can be programmed to flicker or alternate, adding to the sensory disorientation. Fog machines can be used to give the bridge the illusion of floating in midair.

Installation
The installation of spinning tunnels depends upon the circumstances of the location. It has been recommended that the tunnel be installed in a dark location. The illusion of a spinning tunnel works best if there are no external points of reference. The inside of a permanent structure has the benefit of protection from the elements as well as darkness. A tarp-covered enclosure is also a good method for covering the tunnel. Both of these methods also offer protection to patrons from the moving parts, such as the drive motor and the cylinder itself. Another consideration is the entrance and exit. One method of installation is to put the tunnel in a pit equal to the height of the bridge so that patrons can step directly into and out of the tunnel. This is an especially safe method for the exit as the patrons are usually disoriented by the attraction. If the tunnel is installed on a level surface, a ramp should be used, again to provide safety for the user. Steps can be used if space is limited, but lighting should be provided to illuminate the steps for the patrons' safety. The ends of the tunnel need to be enclosed to prevent light entering and to help control the flow of patrons through the attraction. This can be something as simple as plastic or canvas sheets slit like the entrance to a tent or like a coldroom, or it can consist of walls with doors decorated to look like the entrance to a funhouse or a cave. The installation of mirrored surfaces at the ends of the tunnel can create the illusion of infinity.

Several serious Halloween enthusiasts have built their own tunnels using materials available to consumers at local outlets. The plans for these projects can be found at various internet sites and in Halloween trade magazines.

Stationary tunnels
Another type of spinning tunnel is the stationary LED tunnel. Instead of the tunnel spinning around the bridge, LEDs that are imbedded in the walls of the tube are programmed to turn on and off in sequence, presenting the illusion of movement. While the method of visual presentation is different—light is transmitted directly to the eyes rather than reflected off a liner—the effect is the same.

Half-cylinder tunnels
This variety of vortex tunnel is not a cylindrical tunnel. The canopy of the tunnel is an arch that is anchored in place. With the use of LEDs, lasers and/or lighting fixtures in combination with designs applied to the interior of the tunnel, the necessary visual effect can be achieved. As stated above, with the visual system receiving information that the environment is in motion, and the vestibular and kinesthetic systems receiving information that the environment is stable, the visitor will experience vertigo to the point of losing the ability to walk steadily through the attraction. By placing the bridge or walkway that guides the visitor on rockers or otherwise rendering it mildly unstable, the kinesthetic system can also add to the sense of instability for the visitor. Artificial smoke or fog can be used to disguise the floor, taking away a reference point for the visual system.

Safety and health concerns
Any time humans are exposed to electricity and moving parts there are opportunities for injuries or death. Add in the fact that this dark attraction is designed to induce vertigo, and the fact that alcohol may be introduced as part of the party atmosphere of the season, and the chances of an injury increase dramatically. It is the responsibility of the builder/owner/operator to see to it that the attraction is rendered as safe as possible so that patrons of the attraction can enjoy themselves without fear of harm.

Simple things like a hand railing at the entrance and exit, as well as along the walkway inside should help keep users safe from rotating parts and away from electrical connections and wiring. Strip lighting running along the walkway and handrails will help users stay on the walkway. Proper care should be taken to adhere to local building and electrical codes when constructing a spinning tunnel. Cages over spot lights can prevent a bad burn from accidental contact. Motors should have covers to keep patrons safe from hazard. Walls need to be built to enclose the attraction and keep curious people away from the outside of the turning tunnel. Walls also have the advantage of creating a light barrier and putting the ride in darkness.

Selection of the building materials for the tunnel needs to be made bearing in mind the final weight of the construct and any torsional and rotational stresses the framework will be subject to. Failure to account for this could result in the attraction collapsing and causing injury. Use of plastic and PVC piping can help with keeping the tunnel from becoming too heavy. Plans for home-built vortex tunnels are available through trade magazines and on the internet which have taken these engineering challenges into account.

Many of the hazards of a spinning tunnel can be avoided by building a stationary vortex tunnel or a half-cylinder vortex tunnel. The benefit of these type of tunnels is there are fewer moving parts. The downside is that the more expensive electronic lighting and LEDs need to be used to achieve the rotational effect of the spinning tunnel.

Proper warning should be given prior to allowing patrons entrance to the tunnel. A small sign letting users know that vertigo is a likely result should suffice, informing them that their balance and footing will be affected. While this warning may seem redundant as the patron is seeking this result, a reminder can save a trip and fall later. Also, anyone who already has an inner ear disorder may find the attraction to be overwhelming and should be discouraged from entering the attraction.