My website is essentially a wordpress installation in addition to some other small php pages. In order to sync the two websites, I use the following script which syncs both the website's filesystem as well as wordpress's MySQL database. This script takes advantage of rsync, so only differences between the two websites are synced. This is essential since my home server has severely limited bandwidth and can't afford a massive transfer every hour.

#!/bin/sh
#======================================
#=== Website synchronization script ===
#======================================

echo "Syncing website directory with rsync"
rsync -e ssh -avz --exclude="local" --exclude="Stats.html" --exclude="wp-config.php" --bwlimit=15 /var/www/ nexus:/var/www/

echo "Syncing blog database"
#Export the wordpress database
mysqldump -u root -p$PASSWORD blog > /dbtmp/txfr.sql
#Transfer database via rsync
rsync -e ssh -avz --bwlimit=15 /dbtmp/ nexus:/dbtmp/
#Install the remote database
ssh nexus 'mysql -u root -p$PASSWORD blog < /dbtmp/txfr.sql'

A cron job on my home server runs this script every hour (at 5 minutes past the hour). This can be accomplished by running crontab -e and inserting the line:

5 * * * * /root/sync_website.sh

In order to switch jeffheidel.com to my backup server when my home server goes down, I use the following python script:

#!/usr/bin/python

#Script checks if jeffheidel.com is up
#If down, we reassign the DNS records
import urllib
import sys
import os

def reset():
    print "Executing DNS bypass proceedure"
    os.system("/root/bin/updateip_home.sh")
    sys.exit(0)

try:
    a=urllib.urlopen('http://www.jeffheidel.com').getcode()
    if(a!=200):
        reset()
except:
    reset()

print "All's good"

The script /root/bin/updateip_home.sh uses FreeDNS's dyndns wget script to set the record for jeffheidel.com to the current IP address. The python script above script runs periodically using cron. Similarly, on my home server, I have a script which periodically runs this wget script so that the DNS record is restored once my home server is restored.

If things are running normally (both servers are up) you will be able to see my primary server at jeffheidel.com and my backup server at cornell.jeffheidel.com. The only difference between the two websites will be the Server Statistics section.

The background for this program has to do with taking notes in my Algorithms class (CS 4820). This class is excellent for taking notes in Latex since it is highly mathematical in nature. Since I spent last semester doing all of my homework in Latex, I am usually able to keep up with the pace of the lecture without trouble. However, I run into trouble whenever the professor draws a figure on the board. While I do have a Tablet PC, there was never really a good way to insert a handwritten element into my notes. Sure, I could draw in paint or some equivalent, save to a file, and then include the file in my latex document, but, by the time I can manage to do all those steps, the lecture will have already moved on. I needed a way to draw and insert within a matter of seconds.

The program is written in C# and runs on the .NET Windows Presentation Foundation (WPF). This environment was chosen due to the availability of the InkCanvas class, which was extremely easy to use. First, when the program is launched, the user selects the latex file they are working with (Ctrl + O). The program then creates an "images" directory within the same path as the tex file. Then, after a figure is drawn, the user simply needs to push "GEN" or Ctrl + S. This will save the current canvas as a JPG within the images directory and copy Latex code to the clipboard. This code can then be pasted into the document immediately.

If you would like to use this application, feel free to email me or comment below.

Old features from last year:

• Fluorescent White light
• UV Black Light
• Strobe Light
• Laser Spirograph Projector

My bike features 192 individual LEDs controllable over 6 PWM channels by an ATmega microcontroller. Eight light strips are attached to the bike via superglue and zip ties. All connections are watertight. The electronics are housed within a seat pouch which is water resistant as well. The pouch contains a 4Ah Lithium Ion rechargeable battery as well as an Arduino board attached to a custom built MOSFET shield which directly connects to the lights. It is easily detachable from the Arduino, meaning that I can simply unplug the microcontroller in order to update the bike's firmware.

I can select flash patterns via a single button mounted on the handlebars. The microcontroller interprets Morse Code from this button in order to determine which flash pattern to select.

 As a bonus, the black wiring I used matches the bike's existing brake lines very well and as a result looks natural.

 With the microcontroller, I can create various flash patterns. In the video below, I illustrate this. I can program additional flash patterns extremely easily and will in the future.

I have begun the process of migrating old projects and content to this new website. Anything that is below this post has already been added to this site. I did my best to estimate posting dates, but they only serve as an approximation.

In the mean time, the majority of my content is located at my root page.

This was done at the request of my sister who wanted an awesome scene in which someone is struck by a falling tree for one of her school projects. She said that it was impossible to go too far on the effects, so I tried my best.

I have only started using After Effects recently. It is a very powerful program, but it takes practice in order to use it well. This is one of the first After Effects sequences I have produced where I wasn't simply copying a tutorial effect. I think it turned out well, though there are some subtle defects. Regardless, I am happy to get all the practice I can.

Watch in 720p HD for best effect.

For more information about what we do, check out http://cuauv.org.

Check out the library, hosted on Google Code, link below:
https://code.google.com/p/arduino-icm7218-library/

An Arduino hooked up to the icm7218 chip.

The first revision of the robot is featured in the video below:

Unfortunately, the latest revision of the robot was not filmed.

This project is currently on hold indefinitely, but may be picked up in the future.

This was the interface for controlling the robot on the remote PC which I programmed. It would convert a joystick location to two motor PWM output, not a simple task.

Interesting Fact: On it's first outdoor run (which was sadly not filmed), this robot had a mild crash with one of my friend's car leaving a battle scar on my tablet PC that is still there today.

The video is public only to my Facebook friends. If you would like to view the video, feel free to shoot me a friend request on Facebook. In order to view this video, you must be signed in on Facebook.