Image capture for Tektronix TDS 1012 Oscilloscope

README.md

This is a simple Python script to capture screen shots from a Tektronix scope, rotate them to landscape mode and convert them to PNG. The script simply sits in the background monitoring the serial port and creating the images in a specified directory.

The following settings are required on the TDS 1012:

1. Printing in PCX format to the RS232 port.
2. RS232 set to 19200N81.

A null modem cable is required to connect the scope to a PC, I used a USB to DB9 serial adaptor on the PC end.

imagecap.py

#!/usr/bin/env python
#----------------------------------------------------------------------------
# 02-May-2014 ShaneG
#
# Capture data from a Tektronix TDS1012 scope and save as an image.
#----------------------------------------------------------------------------
from sys import argv, stdout
from os import makedirs, remove
from os.path import abspath, exists, isdir, join
from time import sleep, strftime
from PIL import Image
import serial

# What speed to use
BAUD_RATE = 19200

def grabImage(scope, path):
  """ Grab a single image from the scope and save it to a file
  """
  # Create the file
  filename = join(path, strftime("scope_%y%m%d_%H%M%S"))
  output = open(filename + ".pcx", "wb")
  print "Receiving screen dump to '%s'" % filename
  # Now read the data
  bytes = 0
  last = 0
  while True:
    data = scope.read(10240)
    if len(data) == 0:
      break
    output.write(data)
    bytes = bytes + len(data)
    if int(bytes / 10240) > last:
      stdout.write("%dK " % int(bytes / 1024))
      stdout.flush()
      last = int(bytes / 10240)
  output.close()
  print "Saved %d bytes." % bytes
  # Now rotate and convert to a PNG
  im = Image.open(filename + ".pcx")
  im.load()
  im = im.transpose(Image.ROTATE_270)
  im.save(filename + ".png")
  # And delete the PCX file
  remove(filename + ".pcx")

#----------------------------------------------------------------------------
# Main program
#----------------------------------------------------------------------------

if __name__ == "__main__":
  # Set default
  port = "/dev/ttyUSB0"
  path = None
  # Get command line arguments
  index = 1
  while index < len(argv):
    if argv[index] == "--port":
      # Set serial port
      index = index + 1
      port = argv[index]
    elif argv[index] == "--path":
      # Set image directory
      index = index + 1
      path = argv[index]
    else:
      print "ERROR: Unrecognised argument."
      exit(1)
    # Next arg
    index = index + 1
  # Make sure the path exists and is a directory
  if path is None:
    path = "."
  path = abspath(path)
  if not exists(path):
    makedirs(path)
  if not isdir(path):
    print "ERROR: Specified location is not a directory."
    print "       " + path
    exit(1)
  # Set up the serial port
  scope = serial.Serial(port, BAUD_RATE, timeout = 2)
  # And wait for some data
  while True:
    while scope.inWaiting() == 0:
      sleep(0.25)
    grabImage(scope, path)

Works pretty well. Thanks!