LaserBox/Formats and Protocols

This page documents the formats and protocols used in the LaserBox project.

Filesystem Layout

The patterns are stored on an SD card, formatted as FAT16.

Overview

• Root directory holds one directory for each gesture
  • Under each gesture directory, there are numbered pattern files that are chosen randomly each time
• Root directory also holds LASERBOX.LOG which is written to when any events happen

Example

• UP
  • 1.PAT
  • 2.PAT
  • 3.PAT
• DOWN
  • 1.PAT
• LEFT
  • 1.PAT
  • 2.PAT
• RIGHT
  • 1.PAT
  • 2.PAT
  • 3.PAT
  • 4.PAT
• LASERBOX.LOG

Pattern File Format v1

This is the first version of the pattern file format, which is currently in use as of 2017-03-16. Pattern files consist of the following:

• Number of frames in file (one byte)
• Frame data for first frame (12 bytes, 6 per plane)
• Frame data for second frame (12 bytes, 6 per plane)
• ...
• Frame data for last frame (12 bytes, 6 per plane)

Pattern File Format v2

This is the planned next version of the pattern file format, to be implemented soon if time allows. Pattern files consist of the followng:

• Magic string 'PATv2'
• One or more of the following blocks:
  • 0x00 - NoOp - Do nothing, continue on.
  • 0x01 - Delay - Wait a certain amount of time before continuing on.
    • Parameter 1 - 1 byte - Number of milliseconds * 10 to delay (i.e. 25 = 250ms)
  • 0x02 - Load Plane - Load pixel data into a given plane.
    • Parameter 1 - 1 byte - Plane to load (0 = ZY, 1 = XY)
    • Parameter 2 - 6 bytes - Pixel data (each byte is one row, last two bits of each byte are ignored)
  • 0x03 - Load Pixel & Refresh - Load pixel data into a single pixel, then refresh all planes.
    • Parameter 1a - 1 bit (MSB) - Plane to load (0 = ZY, 1 = XY)
    • Parameter 1a - 3 bits - Row to load
    • Parameter 1a - 3 bits - Column to load
    • Parameter 1a - 1 bit (LSB) - Pixel state
  • 0x04 - Refresh All Planes - Push loaded pixel data from the hold registers to the laser outputs.
  • 0xFF - Exit Interpreter - If encountered in a file, cease parsing at that point. If in a live serial stream, drop out of live mode.

Serial Debug Protocol

The USB serial port on the Arduino is used for debugging and status reporting purposes during build and setup.

• PC to LaserBox
  • N - NoOp - Do nothing, continue on.
    • Response - 'OK'
  • L - Live Mode - Begin receiving Pattern File Format v2 data and displaying it live as it it had been read from a file. Returns to this protocol when the Exit Interpreter pattern command is received.
  • S - Status - Output current system status.
    • Response - A bunch of status text intended for humans including current time, cell backhaul status, and resource levels.
  • T - Run Test - Run a self-test procedure.
    • Parameter 1 - 1 character - Which test to run:
      • T - Telemetry (cell backhaul) test
      • S - Storage test
      • G - Sensor test
      • L - Laser test
      • F - Fog test
    • Response - 'OK' or 'FAIL'
• LaserBox to PC
  • All messages begin with two bytes:
    • 'U-' - Unsolicited Message - Not a response to a command, this is a status being sent out for debug purposes.
    • 'R+' - Solicited Response - This is part of a response to a command, but not the last line. The format of the response is command-dependent and defined above.
    • 'R-' - Solicited Response End - This is the last line of the response to a command.