A chase is an electrical application where strings of adjacent light bulbs cycle on and off frequently to give the illusion of lights moving along the string. With computerized

lighting console A lighting control console (also called a lightboard, lighting board, or lighting desk) is an electronic device used in theatrical lighting design to control multiple stage lights at once. They are used throughout the entertainment industry and a ...

s, building chase sequences has become easier, while previously chases used mechanical means, such as a wheel with an electrified spindle which strikes electrical contacts for each circuit. Chase lights (or chaser lights) are often associated with the marquee signs of some movie theaters, and have also been used as a common element of television

game show A game show is a genre of broadcast viewing entertainment (radio, television, internet, stage or other) where contestants compete for a reward. These programs can either be participatory or Let's Play, demonstrative and are typically directed b ...

sets.

Creating a chase effect

In order to achieve a chase "strip lights" are most often used, especially when used in "theatrical" applications. Similar design is used in computing, where it is known as "

marching ants The marching ants effect is an animation technique often found in selection tools of computer graphics programs. It helps the user to distinguish the selection border from the image background by animating the border. The border is a dotted or da ...

" Several separate circuits of lights (called channels) are needed to create a chase effect which is a simulation of motion achieved by turning these circuits ON and OFF in sequence. The standard is 3 or 4 channels. For 4 channels the lights are wired with one common and 4 different feeds. Light #1 is wired with lights #5 & 9 & 13, etc. (+4); Light #2 is wired with lights #6 & 10 & 14, etc. (+4); Light #3 is wired with lights #7 & 11 & 15, etc. (+4); Light #4 is wired with lights #8 & 12 & 16, etc. (+4). Chase_lighting_SMIL

The most common 4 channel chase which is seen in a theater Marquee perimeter lighting and other lighting animation applications consists of 4 channel wired light bulbs and an electronic chaser. The electronic chaser turns channel #1 ON while all the other Channels remain OFF. Then after an adjustable period of time it turns OFF channel #1 while turning ON channel #2, then turn OFF channel #2 while turning ON channel #3, then turn OFF channel #3 while turning ON channel #4, then repeat. This creates the illusion that the lights are moving in one direction. Some digital lighting chasers are made to do the above described single light chase pattern along with other combinations of Turning ON and OFF of the light to create different sequences like forward light chase, backward light chase, bouncing, dark chase (1 channel OFF while all 3 others ON), etc... Also, more than 4 channel chasers are used to create more effects and to animate illuminated objects. Chase circuits using

LEDs A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (cor ...

are commonly built by electronics hobbyists with timer (such as the

555 timer IC The 555 timer IC is an integrated circuit (chip) used in a variety of timer, delay, pulse generation, and oscillator applications. Derivatives provide two ( 556) or four ( 558) timing circuits in one package. The design was first marketed in 197 ...

) and counter (such as the 4017, which allows up to 10 channels)

integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...

s.LED Chaser Circuit Diagram using IC 555 and CD 4017
Circuit Digest

References

{{Reflist Lighting