Alpha 220 LED Sign
|You can find one of these signs for less than $100.|
|220 Full Matrix, (Case 37.7" x 3.8" x 2.9 ") Tricolor|
Install a Serial Port Interface
In this case a KuroBoxPro was used however any Linkstation could be used by accessing the serial port interface.
First, install a serial port interface. There are two physical serial ports on the KuroBoxPro. One serial port on the bottom which is the same as the port on the Linkstation Pro and one on the daughterboard accessible from the front. Both are addressed as /dev/ttyS0. Consider soldering in a pinheader rather than the pressure connector used in the LSPRO method.
|The cheapest TTL/RS232 converter found was from futurelec, however the order is shipped from thailand so it takes 2-3 weeks to get it.||The sign uses a 6 conductor RJ-12 Jack. A snap in RJ-12 jack is used to interface the sign to the serial port converter||The serial port board/connector are then enclosed in a 2 port surface mount housing|
Interface Sign to Serial Port Interface
A standard 6 wire telephone cable meant for a two line phone is used (a 4 wire one will not work) Plug one end into the sign, and one end into the Quick port RJ-12 Jack. Wire the jack into the serial port board as such
Setup the serial port
Adjust the serial port settings, below is a script to do this. This information comes from a FAQ on using the Alpha sign with Linux.
- Links /dev/ttyS0 to /dev/alpha
- Gives everyone read/write access to your sign (/dev/alpha)
- Provides a 9600,E,7,1 connection to the sign (/dev/alpha)
# /usr/local/bin/setledsign #!/bin/sh rm /dev/alpha ln -s /dev/ttyS0 /dev/alpha chmod a+rw /dev/alpha stty 9600 -opost -ocrnl -onlcr cs7 parenb -parodd < /dev/alpha
Wake up the sign and display something on it
# alphamon.pl # #!/usr/bin/perl # # Script will display the contents of /tmp/textfile to the ALPHA 220C LED # Display # # Usage # # alphamon.pl [MODE TAG] [COLORTAG] # Get the attention of the sign print "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; # Tell the sign to print the message $message = `cat /tmp/textfile` ; print "\001" . "Z" . "00" . "\002" . "AA" . "\x1B" . " $ARGV" . "\x1C" . "$ARGV" . $message . "\004";
Alpha Sign Syntax
|\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0||NULL||String of Null packets to get attention of sign|
|\001||SOH||Start of Header|
|Z||Direct at all Signs||Type Code|
|00||All Signs Should Listen||Sign Address|
|\002||Start of Text Character||Start Type|
|A||Text File||Write File Type|
|\x1B||ESC||Start of Mode Field|
|t||compressed text||MODE TAG (see below)|
|\x1C||color control code||Control Code|
|1||red||COLORTAG (see below)|
|Hello World||Text Message|
|\004||EOT||End of Transmission|
MODE TAG and COLORTAG
The sign can be used for a number of purposes (to display weather forecasts from an RSS feed, to display news feeds as a news ticker) As a proof of concept the following script uses the sign to display a stock ticker that gets it's data from yahoo. It then colors the prices green if they are positive/up and red if they are negative/down for the day.
Here it is in action: (clip from a cell phone so quality is somewhat poor)
First install perl and make
apt-get install perl make
Then install the quote package 
wget http://www.circlemud.org/pub/jelson/quote/quote-0.05.tar.gz tar -xvzf quote-0.05.tar.gz cd quote-0.05 ./configure ./make ./make install
install curl and lynx so that they can be used later to get content from the web.
apt-get install curl lynx
Lastly here is a shell script to display the ticker
# /usr/local/bin/leddisplay #!/bin/sh # Stock ticker symbols # PTE=/usr/local/bin stocks=" ^DJI ^IXIC ^GSPC " quote $stocks | cut -d"(" -f1 |sed 's/^/\x1C9 \x7F \x1C3 /' | sed '/ -/s/:/\x1C1/g' | sed '/ +/s/:/\x1C2/g' > /tmp/textfile $PTE/alphamon.pl t A > /dev/alpha