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goofee · **Posted:** Sun Oct 21, 2007 1:27 am

Hi. I had a problem with people changing the channel on the satellite box mid recording so was looking for a way to indicate recorder status. This thread got me started, http://mysettopbox.tv/phpBB2/viewtopic.php?t=12786, but my only serial port is tied up with my IR blaster/receiver and didnâ€™t want to break that. I have one of these relay cards that got me familiar with the parallel port hardware so thought Iâ€™d try that. I also added an LED to show commflaging. I posted all the steps I took, I find it easier to learn new stuff if I see where it came from rather than a step by step drunk monkey approach (although those are nice too)

I robbed +5V from unused hard drive connector, ran through 470ohm resistor to limit current, different colored LEDs, and connect to pins 2 â€“ 9.

Code:

apt-get install python-parallel

edited /usr/bin/recstat.py as follows:

Code:

#!/usr/bin/python

import httplib
import parallel
import time

mythStatus = "localhost:6544"
encoder1 = "Encoder 1 "
encoder2 = "Encoder 2 "
recording = "is local on mythtv and is recording"
watching = "is local on mythtv and is watching"
commflag = "<font class=\"jobrunning\">Flag Commercials</font>"

p = parallel.Parallel() #opens LPT1
p.setData(0) #turn off all lights

while(True):
   total = 0
   conn = httplib.HTTPConnection(mythStatus)
   conn.request("GET", "/")
   r1 = conn.getresponse()
   results = r1.read()

   if (results.find(encoder1+recording)!=-1):
      total = total + 1
   elif (results.find(encoder1+watching)!=-1):
      total = total + 1
   elif (results.find(encoder2+recording)!=-1):
      total = total + 2
   elif (results.find(encoder2+watching)!=-1):
      total = total + 2
   elif(results.find(commflag)!=-1):
       total = total + 4

   p.setData(total)
   time.sleep(60)

the first time I ran it it complained about /dev/parport0 not existing so

Code:

mknod /dev/parport0 c 99 0
chown root:lp /dev/parport0

The above script ran fine (turned lights on and off) but I noticed that while watching live tv or recorded tv, about every minute the video would stutter. I stopped the script and it went away. I tried modifying thornsoftâ€™s babysitt_commflag script to renice to 19 but that didnâ€™t help at all. I found that I coud duplicate the stuttering by hitting refresh on the mythweb/status page in the browser on my laptop while watching videos on my mythbox. So I started looking for a new way to determine encoder status. I found that the inuseprograms table in mythconverg tells me when stuff is recording. Modified again as follows:

Code:

#!/usr/bin/python

import parallel
import time
import MySQLdb

#Connect to mythconverg
db = MySQLdb.connect(host="localhost", user="mythtv", passwd="mythtv", db="mythconverg")
cursor = db.cursor()

p = parallel.Parallel() #opens LPT1
p.setData(0) #turn off all lights  TODO: find current state on pins so other pins can be used for other things

while(True):
   total = 0
   #select data only if recording or flagging on localhost
   cursor.execute("SELECT chanid,recusage FROM inuseprograms WHERE (recusage = 'recorder' AND hostname = 'machinehostname') OR (recusage = 'flagger' AND hostname = 'machinehostname')")
   results = cursor.fetchall()

   for record in results:
       if record[1] == 'flagger':
           total = total + 4  # TODO: math to determine if pin is already on or not
       elif (record[0] / 1000) == 1: #encoder 1
           total = total + 1
       elif (record[0] / 1000) == 2: #encoder 2
           total = toatl + 2
   p.setData(total)  #turn on lights  TODO: math to turn on LEDâ€™s without affecting other pins
   time.sleep(30)

This script seems to work better (no stuttering). Start and stop using

Code:

/etc/init.d/recstat {start|stop|restart|force-reload}

There are a few things Iâ€™d like to change but not sure how at this point. Will keep working on it unless one of you gurus wants to fill me in. I only have one encoder right now but hope to add later. My channels show up as 1505 for 505 so assuming that the 1 would be encoder 1 and if I had a second encoder it would be 2505. I divided 1000 or 2000 to determine encoder. Tried '^1' instead but it didnâ€™t seem to like that. Also if I had 2 flagger instances running it would add again and give me a wrong value.

Anywaysâ€¦Enjoy. Warren.

And of courseâ€¦Disclaimer. Mechanic by trade with no formal computer training. New to linux and knoppmyth. Started with R5E50 now running R5F27. First time ever using python.

Encoder Status LED's Using Parallel Port

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