Step 10 : Software


Assuming that you want to use a computer to control the lights, you will first need sequencing software. There are many software packages to choose from, but most DIY types are using Vixen. It's free, but it's also very flexible and easy to use (and you get outstanding support from the creator).

The chosen software is used to manage the channels and good software like Vixen lets you name the channels and even color code them. You then use the software to turn the lights on and off while music is played and with proper timing, you can make the lights flash to the music. You can also set up songs individually and then combine them together into timed shows.

Step 11 : Data Transmission


From the computer, the data is transmitted to the controller using a variation of one of two protocols. Serial transmission requires only one data line and is how a modem transmits. It requires a start command, 8 bits of data, and a stop command. In addition to the data line, you need at least a ground line. Parallel transmission requires 8 data lines. It transmits the 8 bits of data simultaneously. In addition to the data line you may need other lines such as ground and clock.

With parallel data transmission, it's possible to control the lights directly and use each data line to control a single channel. This type of system is excellent for small displays and beginners as it is cheap to build and easy to set up. However, you are limited to a maximum of 36 channels. You can also use a multiwrite method such as that used in the "Hill 320" controller. This uses multiple parallel transmissions to route the data through a series of chips. This enables you to control multiple channels per line using a parallel port.

Serial and parallel to this point primarily refers to the protocols and not the ports themselves. You can send a serial transmission through a parallel port. In fact you can send multiple simultaneous serial transmissions through a parallel port. This is how an "Olsen 595" control system works. It uses a variation of serial data transmission in which you use an additional line to signal the separation between packets rather than a transmitted command. It has been determined that one parallel port can transmit enough data to support over 8000 channels with plenty of bandwidth to keep up with demanding light shows.

You could send serial data through a USB port (or a serial port, obviously), but the show would look exactly the same and you need to deal with drivers and other things that make it more difficult. Companies like Light-o-Rama use transmissions of small packets of data. The packets contain channels and commands and the controller boards listen for commands that apply to their channels. This has advantages and disadvantages, but is pretty complex to set up and requires programmable boards.

Step 12 : Dimming


The last thing I'll cover is dimming. Up to this point I've only mentioned turning channels on and off. Common household dimmer switches dim lights by modifying the AC waveform. A brief explanation would be that AC power is transmitted as a continuos wave pattern and by removing pieces of each wave, you lower the current and dim the lights. You can then ramp/fade the lights by varying the amount of waveform removed over time. In order to dim, the hardware has to be compatible. Some examples would be the 595 based "Horning Dimmer" and PIC (Programmable Interupt Controller) based "Renard."