# starway
A set of java classes to emit opc packets driving a LEDscape array - used for StarWay sculpture in Reno 
Key feautures:
1) mapping stars to leds - a config file allows selection of multiple leds to act as a single 'star'
2) generation of valid opc packets to drive the leds
3) 'twinkle' mode which illuminates all the stars with a shade at a slightly varying intensity
4) 'action' mode which is activated when a specific star is selected (via rfid)
5) mapping of rfid tokens to stars

Hardware:

1) Adafruit mifare Rfid shield  (https://www.adafruit.com/products/789)
2) Arduino Mega (with rfid sheild plugged in) 
    Arduino runs the 'classic mi-fare' example from adafruit's library
connects over USB to Beagleboneblack number 1
3) BBB #1 runs the java program from this directory reading from 
/dev/ttyACM0 (the arduino) and sending OPC udp packets to a second BBB
4) BBB #2 runs LEDscape https://github.com/Yona-Appletree/LEDscape 
configured to talk to 48*3 Leds on each of the first 5 data lines.
Notice that the startup script does the appropriate stty actions
to set the USB tty to 9600 baud etc.
5) The main sculpture consists of 693 RGB LEDs
One data pin drives all the LEDs in each diamond (the Sculpture is made of
5 diamonds (A->E), each with upto 48 (1->48) stars, each star containing 3 WS281x LEDs)
6) an additional central star (larger and brighter than the rest) consists
of 24 leds in a neopixel ring. - this is on data line 6 of BBB #2 and 
called 'F1' in the config file.
7) The Rfid console also has a lighting effect. This is provided by a
second install of LEDScape running on BBB #1 - driving a second neopixel
ring under the RFID reader (this is physically mounted on the BBB). This is
'CONSOLE' in the config file.


Notes:
i) the only reason for having 2 beaglebones is that for optimum
viewing the RFID reader needs to be 30+ feet from the Stars. 
This is too long for USB. We used an old airport express as a
DHCP router/switch (this makes it easier to plug other things into the
BBBs than static IP addressing) and connected the 2 ends over an ethernet cable.

ii) The Beaglebone is nominally a 3.3v device - the LEDs are 5v.
fortunately they work without a level switcher between the two. 
(This requires that the first LED in each diamond is close to the BBB#1,
in then passes on a 5volt signal - acting as a buffer)

iii) the OPC UDP packets sent by this software are quite large 
at 2083 bytes (not counting the header). This works fine over a LAN
but will probably not work over WANs or through anything with a smaller MTU,
unless UDP fragmentation happens to be working. Ideally LEDscape would be
on the same host as the RFID and send the packets over the loopback interface.

iv) this version of the software only remembers the mapping of rfids to stars
within a run of the program. When the java process finishes, any mapping is 
erased, next time you run - all stars will be in twinkle mode and the first
RFID presented (irrespective of serial number) will select the first star in
the sequence.

Building/testing software:
1) follow the adafruit guide on building the rfid library and sample code
2) install oracle java8 on the beaglebone #1 (or in theory a pi or other small
linux with USB serial support and a working ethernet)
3) build this software on your laptop (or elsewhere - even on the BBB if you must) 
with the command
mvn package
copy the resulting .jar file to the beaglebone #1
run 
java -cp starway-1.0-SNAPSHOT.jar us.yopet.starway.MkConfig bigstar.json
to generate the config file - edit it to configure serial ports/ipaddresses
4) on BBB 2 install LEDscape (following the instructions in the git tree)
 - configure the config file for 5 strings of 144 LEDs
and select an idle mode ('fade' works well)
leave LEDscape running
5) run this software on BBB1 
java --jar starway-1.0-SNAPSHOT.jar  bigstar.json

the stars should now twinkle.

6) present an RFID.

Handy HACKS:
If you run a copy of this software on BBB #2 (with rfid set to /dev/zero and ipaddress to 127.0.0.1) 
you can use it to provide a stand-alone 'twinkle' mode in the absense of a console.

If you don't like the 'random' order the stars are selected in, re-generate the config file.
This will create a different running order.