Intelligent lighting
More recently the term has fallen into disuse as abilities once reserved to a specific category of lighting instruments (most notably colour changing and variable focus) have become pervasive across a range of fixtures.
There are many patents for intelligent lighting dating back from 1906, with Edmond Sohlberg of Kansas City, USA.
1925 saw the first use of electrical motors to move the fixture, and with it the beam position, by Herbet F. King (US patent number: 1,680,685).
In 1936 US patent number 2,054,224 was granted to a similar device, with which the pan and tilt were controlled by means of a joystick as opposed to switches.
During this period, Century Lighting (now Strand) started retailing such units specially made to order, retrofitted onto any of their existing lanterns up to 750 W to control pan and tilt.
George Izenour made the next breakthrough in 1969 with the first ever fixture to use a mirror on the end of an ellipsoidal to redirect the beam of light remotely.
With only pan, tilt, and color functions, and at 1.2 meters long and weighing in at 97 kilograms including the ballast, they were heavy and cumbersome.
Lighting is typically pre-programmed and played back using only simple commands, although moving heads can be controlled “live” if the operator is sufficiently experienced.
The vast majority of moving heads are controlled using the DMX protocol, usually using dedicated twisted pair, shielded cable [1] with 5-pin XLR connectors at the ends.
The central lighting desk transmits data on these channels which the intelligent fixture interprets as value settings for each of its many variables, including color, pattern, focus, prism, pan (horizontal swing), tilt (vertical swing), rotation speed, and animation.
Since moving heads did not attain prominence until DMX's predecessor, AMX, or Analog Multiplex had passed the zenith of its popularity.
Very few moving heads use analogue control, due to crippling restrictions on bandwidth, data transfer speeds and potential inaccuracy.
A slew of products are available on the market to allow operators and programmers to easily control all of these channels on multiple fixtures.
Lighting boards are still the most common control mechanism, but many programmers use computer software to do the job.
Software is now available that provides a rendered preview of the output produced by the rig once fixtures are connected to the program or console.
Naturally, there are exceptions to this rule, most notably the use of large numbers of moving heads for international sporting events, such as the Commonwealth Games[5] or Olympic Games,[6] where many thousands of separate automated fixtures are often used to light the opening and closing ceremonies.
The 2008 Summer Olympics, in Beijing, had a rig of around 2,300 intelligent fixtures which is "the largest single automated lighting system ever assembled for a single event"[7] Usually, however, the use of intelligent lights is confined to theatre, concerts, nightclubs, and churches where the versatility of these fixtures can be utilised to its best extent.
Active use of automated lights suggests that the luminaire is used to perform tasks which would otherwise require human involvement, or be simply impossible with conventional fixtures.
For instance, a number of moving heads producing tightly focused, pure white beams straight down onto the stage will produce a fantastic effect reminiscent of searchlights from a helicopter (especially if a smoke machine or hazer is used to make the beams visible).
Profile lights generally contain features like gobos and prisms, whereas wash lights have simpler optics and a wider beam aperture resulting in wider beam angle, which may be altered by internal lenses or “frost effects”.
Basic, low cost fixtures that are marketed primarily to DJ's, club venues, or for retail in novelty stores are not controllable beyond simply powering the device on or off.
The introduction of devices referred to as "Auto-yokes", after the original design created by the company City Theatrical, blurs the line between a "conventional" and "intelligent" fixture.
When combined with an LED fixture or colour scroller, the most common features of an automated light can be readily duplicated.
Much smoother operation can be achieved through one axis of a moving head luminaire describing a circle (usually pan) and the other (tilt) changes the diameter of the circular movement.
