Perl code to control an LED Scrolling sign
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This is a Perl module that provides very basic communications functionality with wall-mounted LED signs capable of displaying single-line alpha-numeric text.

Sign Compatibilty

This library was designed and tested with the following signs:

  • Series 300 Alpha LED Sign, by Adaptive Micro Systems (Milwaukee, WI)
  • Model 320C Alpha LED Sign, by Spectrum Corporation (Houston, TX)

Compatibility with other sign models may be possible but has not been tested. Although the communications protocol allows for multiple signs to be daisy-chained (via RS485) and assigned unique addresses so that they can be programmed individually or by groups, this library was only designed for single device communication (vs RS232).

Sign Hardware Overview

The sign has several kilobytes (typically as 32kb) of persistent memory that is used to store all of the TEXT files, STRING files, and DOT graphics. There are a total of 95 possible "file label" slots, which are given one-character ASCII names in the range of 0x20 through 0x7E inclusive. Each of these file labels can be used for one of the three purposes already mentioned, but changing the designated purpose of a file label will erase its contents.

The size of each file label is specified at the time its purpose is configured and the memory used for its storage is taken from the total amount of persistent memory available on the device. Message files cannot be written to any files (other than "0" or "A") until memory is explicitly allocated for that file label using the Set Memory Configuration command.

File label "0" is used for Priority messages and is pre-configured to use a set region of memory outside of the Memory Pool. When data is written to the Priority message file, all other text files will stop being displayed. When the Priority message file is erased, then normal display of other text files will resume. The Priority message file is limited to 125 characters. The size, purpose, and operating hours of the Priority message file cannot be reconfigured.

Library Dependencies

In addition to Perl 5, you will need to install one of the following serial port modules from CPAN, depending on your operating system:

  • Win32::SerialPort
  • Device::SerialPort

The example web interface requires the following Perl module:

  • CGI