I bookmark. A lot.

I’ve been working on a Python script to help me parse (and make sense) of all the bookmarks I consume on a daily basis. I was interested in just how many I accumulate daily, monthly, and yearly. It turns out, a lot.Output

Raspberry Pi + Garage door opener: Part 2

In Part 1 of my ‘Raspberry Pi + Garage door’ series, I showed a super simple way to control a garage door with a script that could potentially be ran from the Internet.

This part expands on that and tackles the issue: ‘How do I know the state of my garage door if I’m not at home?’

Because the code operates no differently than someone pressing a single button on the remote control, you would normally have to look with your own eyes to see if you were closing, stopping, or opening the garage door. This can be an issue when your eyes are nowhere close to it.

I wanted to come up with a solution that didn’t involve running new equipment such as a switch to detect the door’s orientation. I decided to utilize what I already had in the garage: A camera. Namely, this one: Foscam FI8910W

The idea is to use the camera to grab an image, pipe that image into OpenCV to detect known objects, and then declare the door open or closed based off of those results.

I whipped up a couple of shapes in Photoshop to stick on the inside of my door:



Shapes taped to the inside of the garage door

I then cropped out the shapes from the above picture to make templates for OpenCV to match.

Templates for OpenCV

The basic algorithm is this:

  1. Get the latest image from the camera
  2. Look for our templates with OpenCV
  3. If all objects (templates) were detected, the door is closed – otherwise it’s open
Shapes successfully detected


To help make step 3 more accurate, I added a horizontal threshold value which is defined in the configuration file. Basically, we’re using this to make sure we didn’t get a false positive – if the objects we detect are horizontally aligned, we can be pretty certain we have the right ones.

I was happy to find that the shapes worked well in low-light conditions. This may be due to the fact that my garage isn’t very deep so the IR range is sufficient, as well as the high contrast of black shapes on white paper.

Currently I have some experimental code in the project for detecting state changes. This will not only provide more information (e.g. the door is opening because we detect the pentagon has gone up x pixels), but is good for events (e.g. when the alarm system is on, let me know if the door has any state change).

I’ve tested running this on the Raspberry Pi and it works fine, though it can be a good bit slower than a full-blown machine. I have a Raspberry Pi 2 on order and it’ll be interesting to see the difference. Since this code doesn’t need anything specific to the Raspberry Pi, someone may prefer to run it on a faster box to get more info in the short time span it takes for a door to open or close.

I’ve created a video to demo the script in action!

GitHub: https://github.com/twstokes/door_detect

Detecting Smith numbers

After learning about Smith numbers today I cooked up this script fairly quickly. There are many places where it could be optimized and cleaned up but that wasn’t really the point – I just needed something that was accurate, and I’m pretty sure this is.

It also helped me to learn about the ulimit command after running it with a HUGE number that had taken up about 7GB of swap before I had to kill the process remotely via SSH…

# smith number detector - TWS 1-12-13

def detectSmith(num):
  if(sumFactors(num) == sumDigits(num)):
    return True
    return False

# calculate the sum of the factors
def sumFactors(num):
  factorList = factors(num)
  sum = 0

  for factor in factorList:
    if factor > 9:
      # if a number (base ten) has multiple digits it has to be broken down
      sum = sum + sumDigits(factor)
      sum = sum + factor

  return sum

# sum the digits in a number with two or more
def sumDigits(num):
  sum = 0  

  if num > 9:
    while num > 9:
      sum = sum + num % 10
      num = num / 10
    sum = sum + num
    return sum
    # should never reach this
    return num

def factors(num):
  primeFactorList = []

  factor = lowestPrimeFactor(num)
  currentNum = num

  while factor != -1:
    currentNum = currentNum / factor
    factor = lowestPrimeFactor(currentNum)

  if(currentNum != num):
    # preventing returning the number passed in

  return primeFactorList

def lowestPrimeFactor(num):
  for x in range(2, (num / 2) + 1):
    if(num % x == 0):
      return x
  return -1

for number in range(1, 1000):
    print "The number", number, "is a Smith number."

A simple Linux content search script

A simple script I use for work to search the contents of files. It just wraps up ‘find’ and ‘grep’ to recursively search and display the location of the file.

# Tanner Stokes - 8-23-12
# Search contents of files

if [ -z "$1" ] || [ -z "$2" ]
echo "Usage: csearch \"filetype\" \"content\""
echo "ex: csearch \"*.php\" \"my_function()\""
exit 1

find . -name "$1" -exec grep -Hn "$2" {} \;

Changing an LCD string on a Dell server remotely with Python

Here’s a little Python script I cooked up for work. We often have to change the custom LCD string on boxes if the machine is given a new name. Before, we’d have to restart a machine to access the DRAC configuration to change the name. With this script, all you have to do is enable IPMI through the DRAC remotely (if it isn’t already enabled), and know the correct credentials.

If the LCD isn’t set to view the custom string, you should be able to change it from the front of the box. As you can see, the function that I have commented out at the bottom is supposed to do this for you, but I never got it to work.

You may have to change ‘/usr/sbin/ipmitool’ to your appropriate path.

import os

# Tanner Stokes - tannr.com - 2-26-10
# This script changes the LCD user string on Dell machines that conform to IPMI 2.0

sp_hostname = raw_input ("\nEnter DNS or IP of SP: ");
user_string = raw_input("Enter LCD string: ")

hex_string = ""

for x in user_string:
 	hex_string += hex(ord(x))
	# add space between each hex output
	hex_string += " "

print '\nTrying to change LCD string on '+sp_hostname+'...'

return_val = os.system('/usr/sbin/ipmitool -H '+sp_hostname+' -I lan -U root raw 0x6 0x58 193 0 0 '+str(len(user_string))+' '+hex_string)

if (return_val == 0):
	print 'LCD string changed successfully.\n'
	print '\nNon-zero return value, something went wrong.'
	print 'Make sure IPMI is enabled on the remote host and the DNS or IP is correct.\n'

# this function supposedly sets the user string to show on the LCD, but never got it to work
# this can be changed from the front of the box anyway
# os.system('/usr/sbin/ipmitool -H '+sp_dns+' -I lan -U root raw 0x6 0x58 194 0')

Sending Growl messages over a network with Python

6-6-12 – This script is really old and may not work with current versions of Growl. There are some good libraries to choose from and I’d recommend looking at them instead.

Updated 12-4-10 – minor code updates
I have yet another script. This one is actually my first one in Python, which is kind of sad after all the good things I’ve heard about the language. This time I didn’t actually write the entire script – I simply added to one that had already been written to give it more functionality.

The original script was found here: http://the.taoofmac.com/space/Projects/netgrowl and almost all credit goes to it’s author, as I only added a little bit more to it.

What this version does is send a Growl message over UDP to a Mac (running Growl and configured to listen for incoming notifications) using Python. I thought this was really cool – I could script my remote Linux machines (or whatever OS) to send messages to my main Mac.

What I added was the ability to have command line arguments so that it would be easier to change options on the fly and also easier to script.

Running ./netgrowl.py -h will give you the following:

#!/usr/bin/env python

# Updated 12-4-2010
# Altered 1-17-2010 - Tanner Stokes - www.tannr.com
# Added support for command line arguments

# """Growl 0.6 Network Protocol Client for Python"""
# __version__ = "0.6.3"
# __author__ = "Rui Carmo (http://the.taoofmac.com)"
# __copyright__ = "(C) 2004 Rui Carmo. Code under BSD License."
# __contributors__ = "Ingmar J Stein (Growl Team), John Morrissey (hashlib patch)"

  import hashlib
  md5_constructor = hashlib.md5
except ImportError:
  import md5
  md5_constructor = md5.new

import struct
# needed for command line arguments
import sys
import getopt

from socket import AF_INET, SOCK_DGRAM, socket


def main(argv):

    # default to sending to localhost
    host = "localhost"
    # default title
    title = "Title"
    # default description
    description = "Description"
    # default priority
    priority = 0
    # default stickiness
    sticky = False

    # if no arguments are given, show usage
    if(len(argv) < 1):

        opts, args = getopt.getopt(argv, "hH:t:d:p:s")
    except getopt.GetoptError:
    for opt, arg in opts:
        if opt in ("-h"):
        elif opt in ("-H"):
            host = arg
        elif opt in ("-t"):
            title = arg
        elif opt in ("-d"):
            description = arg
        elif opt in ("-p"):
            # acceptable values: -2 to 2
            priority = int(arg)
        elif opt in ("-s"):
            sticky = True

    # connect up to Growl server machine
    addr = (host, GROWL_UDP_PORT)

    s = socket(AF_INET,SOCK_DGRAM)
    # register application with remote Growl
    p = GrowlRegistrationPacket()
    # send registration packet
    s.sendto(p.payload(), addr)

    # assemble notification packet
    p = GrowlNotificationPacket(title=title, description=description, priority=priority, sticky=sticky)

    # send notification packet
    s.sendto(p.payload(), addr)

def usage():
    print """Usage: ./netgrowl.py [-hs] [-H hostname] [-t title] [-d description] [-p priority]
Send Growl messages over UDP
  -h help
  -H specify host
  -t title
  -d description
  -p priority [-2 to 2]
  -s make sticky"""

class GrowlRegistrationPacket:
  """Builds a Growl Network Registration packet.
     Defaults to emulating the command-line growlnotify utility."""

  def __init__(self, application="NetGrowl", password = None ):
    self.notifications = []
    self.defaults = [] # array of indexes into notifications
    self.application = application.encode("utf-8")
    self.password = password
  # end def

  def addNotification(self, notification="Command-Line Growl Notification", enabled=True):
    """Adds a notification type and sets whether it is enabled on the GUI"""
    if enabled:
  # end def

  def payload(self):
    """Returns the packet payload."""
    self.data = struct.pack( "!BBH",
                             len(self.application) )
    self.data += struct.pack( "BB",
                              len(self.defaults) )
    self.data += self.application
    for notification in self.notifications:
      encoded = notification.encode("utf-8")
      self.data += struct.pack("!H", len(encoded))
      self.data += encoded
    for default in self.defaults:
      self.data += struct.pack("B", default)
    self.checksum = md5_constructor()
    if self.password:
    self.data += self.checksum.digest()
    return self.data
  # end def
# end class

class GrowlNotificationPacket:
  """Builds a Growl Network Notification packet.
     Defaults to emulating the command-line growlnotify utility."""

  def __init__(self, application="NetGrowl",
               notification="Command-Line Growl Notification", title="Title",
               description="Description", priority = 0, sticky = False, password = None ):

    self.application  = application.encode("utf-8")
    self.notification = notification.encode("utf-8")
    self.title        = title.encode("utf-8")
    self.description  = description.encode("utf-8")
    flags = (priority & 0x07) * 2
    if priority < 0:
      flags |= 0x08
    if sticky:
      flags = flags | 0x0100
    self.data = struct.pack( "!BBHHHHH",
                             len(self.application) )
    self.data += self.notification
    self.data += self.title
    self.data += self.description
    self.data += self.application
    self.checksum = md5_constructor()
    if password:
    self.data += self.checksum.digest()
  # end def

  def payload(self):
    """Returns the packet payload."""
    return self.data
  # end def
# end class

if __name__ == '__main__':

    # send command line arguments to main() function

Super simple BASH script to monitor a process

Here’s a little BASH script that I made to monitor a virtual machine on an OS X box. Basically when its CPU usage gets higher than 75%, I get a Growl notification and a spoken warning from Bruce – one of the many Mac voices.

One thing to note:

ps -eo %cpu 207 | tail -1

is where the magic is done. Replace ‘207’ with the PID of whatever you want to monitor. It would be wiser to make this script monitor the process by name, but in my case I have the VM running all the time.


# CPU threshold
readonly THRESHOLD=75

while true; do
    # make the output of our command a variable
    set `ps -eo %cpu 207 | tail -1`
    # turn float into int by truncating from decimal after
    # if our CPU usage is above our threshold
    if [ "$toInt" -gt "$THRESHOLD" ]; then	
        # if we haven't displayed a Growl notification for this alarm
        if [ "$alarmState" -eq "0" ]; then	
            # display a Growl notification
            growlnotify -sm "`date` Warning! CPU is at $toInt!"
        # shout out our warning
        say -v Bruce "Warning! CPU is at $toInt!"
        # consider putting 'sleep' here
        # CPU usage is below our threshold
    # pause the script for a second
    sleep 1

Send preset messages automatically with Adium and AppleScript

After coming across this article today on Reddit, I decided to cook up a little AppleScript to accomplish the same task for us Mac users.

Disclaimer: I would never do this to my boss, so if any potential employers are out there scoping out my blog please know that it’s truly for entertainment purposes…

OK so here’s the script.

  • It will send all of the messages in a text file to whatever screen name you choose at defined or random intervals
  • Adium needs to be loaded and you need to be signed in
  • You need to create the text file and know its path. It expects the file to be in plain text and each message to be separated by a new line. I haven’t experimented with anything other than plain text and you could possibly have encoding issues and send some offensive message in Chinese.

Select all of the text below and copy it. Though it’s cut off on the sides it will still grab it all.

-- your Adium IM account name

-- screen name of target

-- path of input file with messages separated by a newline
-- example: "/Users/JohnDoe/Desktop/messages.txt"
set filePath to "PATHTOFILEHERE"

-- set minimum amount of time to wait before sending messages in seconds
set lowerTime to 200
-- set maximum amount of time to wait before sending messages in seconds
set upperTime to 800

-- open file for input and set variable for text
set textFile to (open for access (POSIX file filePath))
set textInput to (read textFile for (get eof textFile))
close access textFile

-- make a list of messages from every new line in the text file
set messages to every paragraph of textInput

-- make our counter variable the number of how many messages we have
set counter to count messages

-- send messages to our target at different intervals until we're out
repeat with counter from 1 to counter
	-- add a little bit of randomness to the delay
	delay (random number from lowerTime to upperTime)
	-- tell Adium to send the current message to our target
	tell application "Adium"
		-- set our current message to whatever message we're at
		set currentmessage to item counter of messages
		-- start a new chat with the target
		tell account imAccnt to set savedChat to make new chat with contacts {contact targetName} with new chat window
		send savedChat message currentmessage
	end tell
end repeat