Total Station and GNU/Linux: Zeiss Elta R55 done!

The pySerial library is really good. Today I installed it and in half an hour I got acquainted with its class methods, even though I have little knowledge about serial ports and the like.

With some trial and error about the connection parameters, I was even able to solve the problem with non-printable characters, tweaking the bytesize of the connection.

Briefly, these are the steps I did in the interactive ipython console:

  1. >>> import serial
    >>> ser = serial.Serial('/dev/ttyUSB0', \
    baudrate=9600, bytesize=serial.SEVENBITS, timeout=0, \
    parity=serial.PARITY_NONE, rtscts=1)
  2. at this point, start the transfer from the device
  3. check that you have received some data:
    >>> ser.inWaiting()

    A non-zero result means that you have received something.

  4. I saved this value to use it with the read() method of the Serial class:
    >>> n = ser.inWaiting()
    >>> result =
  5. The result object is a string, seeing its contents is as simple as:
    >>> print(result)
    0001 OR.COOR
    0002                   0S        X        0.000 Y         0.000 Z     0.000
    0003                                            Om     397.0370
    0004 POLAR
    0005 INPUT                       th       1.500 ih        0.000
    0006 INPUT                       th       0.000 ih        0.000 Z     0.000
    0007                   1         X       -0.472 Y         1.576 Z     0.004

    As you can see, there are no errors after the END sentence, because the serial connection is handled gracefully now. The previous attempt with cat /dev/ttyUSB0 was a bit brutal…

For now, that’s all. I go back studying and maybe also writing some Python code for this Total Station. If you have got a total station and want to contribute to this project, let me know by leaving a comment here.

Pubblicato da

Stefano Costa

Archaeologist, I study the Late Antique and Early Medieval/Byzantine period on the northern side of the Mediterranean, focusing on pottery usage patterns. I'm also involved in open source and open knowledge communities, like OSGeo, the IOSA project and the Open Knowledge Foundation.


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