OpenDRO is the name of the open source software that runs on the ShumaTech DRO-375 and DRO-550 products.  It is released under the GPLv3 license so that anyone can use the software and contribute to the project so long as they respect the terms of the license.  The software is constantly evolving and improving so we suggest you check the current Release Notes periodically for new features and fixes.  If you are interested in modifying the source code, further detail can be found in the Build Instructions.  The software is hosted on SourceForge where you can find the C source code as well as the binary images for each ShumaTech product. 

OpenDRO incorporates a very large feature set and the major features are summarized below.  The OpenDRO User's Guide has complete information on the functionality and operation of OpenDRO.


  • Support for Chinese (24BIT, 21BIT, BCD7, and BIN6 protocols) and quadrature scales
  • Chinese scale protocol auto-detection
  • Fast scale reading for Chinese scales with a display update rate of up to 50 times a second
  • Scale summing
  • Adaptive moving average scale filtering to minimize jitter
  • Linear error correction


  • Absolute and incremental zeros
  • Enter zero values for both coordinate systems via keypad
  • Enter incremental presets via keypad
  • Enter fractional numbers via keypad
  • Zero warning with axis blink and piezo buzzer
  • Electronic edge finder zeroing with audible alert


  • Display units in inches or millimeters (mm)
  • Configurable display precision up 4 decimal places in inch mode (3 for mm mode)
  • Auto-precision to automatically reduce precision to fit the display
  • Fractional display in 64ths
  • Raw scale count display
  • Feed rate display in inches per minute or millimeters per minute
  • Tachometer display in RPM or surface feet per minute (SFM)
  • Display brightness configurable in 20% increments


  • Tool offsets
  • Bolthole circles
  • Sub-datum workspaces
  • Hole grids
  • Radius cutting (concave and convex)
  • Compound vectoring
  • Centerline calculation
  • Diameter mode
  • Auto power off and on


  • USB and RS-232 serial interfaces
  • Software upgradeable
  • Lua command interface
  • Run Lua scripts from keypad
  • SD memory card support (SD and SDHC)
  • Lua shell with advanced editing (edit keys, history, and completion)
  • Windows virtual DRO application to control DRO remotely


  • Reverse polish notation (RPN) calculator with a 4 level stack
  • RPN calculator operations: addition, subtraction, multiplication, division, cosine, sine, tangent, square root, power, memory, scale transfer, fractions, and more
  • Audible key presses

.. and more!