Simulation

The particle platform simulation is built on top of the Avrora framework. It simulates nodes of a network of fold-able chains, that can be used for shape shifting displays or to build programmable matter in general as presented by Matteo Lasagni in Force-Guiding Particle Chains for Shape-Shifting Displays (http://arxiv.org/abs/1402.2507). The simulation constructs and connects multiple nodes to a network that allows bidirectional communication in between nodes. Each node in the simulation is abstracted by

• a particle platform,
• the micro controller (Atmega16), and
• the micro controller firmware.

Among others the simulation allows to

• inspect registers at runtime,
• monitor actions,
• collect lots of statistics, and
• log network/node interactions for later usage such as replay for visualization or other simulation tools.

Example video

• on GitHub
• on Google

Build JAR with dependencies

mvn assembly:assembly -DskipTests

Start simulation

java -jar ./target/particleplatform-0.0.1-SNAPSHOT-jar-with-dependencies.jar <arguments>

Recommended arguments:

-banner=false 
-status-timing=true 
-verbose=all 
-seconds-precision=11 
-action=simulate 
-simulation=particle-network 
-rowcount=2 -columncount=2 
-seconds=1000E-6 
-report-seconds=true 
-platform=particle 
-arch=avr 
-clockspeed=8000000 
-monitors=calls,retaddr,particle,interrupts,memory 
-dump-writes=true 
-show-interrupts=true 
-invocations-only=false 
-low-addresses=true 
-particle-log-file=true 
-particle-facets=state,break,wires 
-input=elf 
-throughput=true
/path_to/node_firmware.elf /optional_path_to/communication_unit_firmware.elf

Network Geometry

The network geomertry is defined by -rowcount=<rows> -columncount=<columns>. With respect to the recommended arguments a simulation would simulate a (2 x 2) network.

Network by a (5 x 3) example

(0,0)
   |
(1,1) -- (1,2) -- (1,3)
   |           |           |
(2,1)    (2,2)    (2,3)
   |           |           |
(3,1)    (3,2)    (3,3)
   |           |           |
(4,1)    (4,2)    (4,3)
   |           |           |
(5,1)    (5,2)    (5,3)

The node at address (0,0) is the communication unit and optional. It is instanciated whenever the arguments provide a second firmware. With the recommended arguments the simulation would run /optional_path_to/communication_unit_firmware.elf program on the communication unit. Nodes at any address row > 0 && col > 0 will run the /path_to/node_firmware.elf program according to the recommended arguments.

Logging

Development logging an be configured in *log4j.properties". The logfile in /var/tmp/particle-platform-simulation.log is meant for development purpose.

Particle logging is activated by -particle-log-file=true and can be found in /tmp/particle-states.log:

   0  0:00:00.00000037585  WIRE[rx-north] <- high
   0  0:00:00.00000037585  WIRE[rx-south] <- high
   1  0:00:00.00000037585  WIRE[rx-north] <- high
   2  0:00:00.00000037585  WIRE[rx-north] <- high
   2  0:00:00.00000037585  WIRE[rx-south] <- high
   3  0:00:00.00000037585  WIRE[rx-north] <- high
   4  0:00:00.00000037585  WIRE[rx-south] <- high
   0  0:00:00.00000050057  SRAM[SREG.(I | T | H | S | V | N | Z | C)] <- (0b00000000)
   1  0:00:00.00000050057  SRAM[SREG.(I | T | H | S | V | N | Z | C)] <- (0b00000000)
   2  0:00:00.00000050057  SRAM[SREG.(I | T | H | S | V | N | Z | C)] <- (0b00000000)

The register monitored for the output in the example above can be configured in ParticleStateDescriptoin.json.

ParticleStateDescriptoin.json

The json object is a description of registers to be monitored. It defines

• enums,
• structures
• type sizes nd
• the SRAM address on the microcontroller.

One may use the auto generator written in python (see full example).

Obtaining property address for ParticleStateDescriptoin.json

The property address corresponds to the symbol address obtained with readelf -a /path_to/node_firmware.elf in the symtab minus the offset. As an example address of the symbol ParticleAttributes

38: 00800061    17 OBJECT  GLOBAL DEFAULT    2 ParticleAttributes

is:

0x00800061 - 0x00800000 = 97

Future Work

• For communication from/to particle nodes the Avrora's serial monitor (edu.ucla.cs.compilers.avrora.avrora.monitors.SerialMonitor) may be utilized.
• Energy profiling is to be implemented for the platform's off chip devices.