Saturday, April 10, 2010
Alright so I havent posted in a while, and the novelty of the wm+ has worn off. I dont have the funding to start a drone project right now, mainly since I’m a broke college student. And even if I did have the money, I dont think I would have the time this semester. I can barely manage to make it to classes right now. But it was from that problem that my last project took shape and has been helping me make it to my classes, making sure I dont fail out.
A little background info first: my city (Gainesville FL) recently put gps systems in most of their busses, which can be checked from the internet. Cool huh? It partially makes up for the fact that busses follow their schedule with an error of + or - 10 minutes (for a 40 minute route). While this is great, I found myself checking the computer every 30 seconds when I woke up, or my old computer would fail to shut down properly leaving it on all day while I wasnt home, not so good for a laptop. I wanted a way to be notified of when I actually had to get my butt out of the door and head to the bus, preferably without using my computer. Well, having just started to play around with the wiznet ethernet module (which comes on the arduino ethernet shield), I decided to make this my next project. So without further ado, I present the Bus Notifier!
I started by finding the static IP address for my bus's website, but since it is php based, the arduino obviously couldnt do anything with it. After mucking around, I found a text based version which was much more useful. The hardest parts of the project were creating a good string parsing algorithm to find just the info I wanted, and then figuring out which string tokens I wanted to make my program look for, signifying a change of state. The three states I decided upon were: nowhere near your apt, stopped somewhat close (for some reason my bus stops at one specific spot for like 10-15 minutes and just sits…yea really annoying) , and the last state is “the bus is coming, get out there!”. To allow me to know what state the bus(or busses) were in, I just used three leds, red, yellow, and green respectively. Later I added a piezo buzzer for the “get out there” state. It worked great for about three months in this state but eventually website updated and all my string parsing had to be redone. So on the next revision, I made the string parsing VERY easy to work with in case of later changes. It has been working this way every morning for the last three or so months.
Another kinda cool module I added was the ability to tweet the location of each of the busses every five minutes. I know this might seem stupid at first, but given the fact that twitter is very easy (and free) to check via text message, this allows me to check the location of the busses once I get out of class with nothing more than a “GET knuckles904” text message to twitter’s shortcode. It gives me the functionality of having a smartphone and internet plan without all the cost.
It took a lot of work, and several revisions to get everything working right but for the past 6 months, but of all the projects Ive spent time on, this has by far been the most useful. I feel I have actually gotten a return on my time investment on this one.
I am posting my most current code (just barely fits in a 168) below, as well as some links that are useful to see. Feel free to adapt any part of this code to your project. I am very proud of it, especially the new string searching function. Just please give credit where its due, and if possible link back here. Also as with all my other posts, any click to the “sponsors” on the right of the page is much appreciated.
http://www.arduino.cc/playground/Code/TwitterLibrary Makes Tweeting a cinch
http://ufl.transloc.com/ Gainesville’s GPS Bus website
http://ufl.transloc.com/t/ Text based version
http://www.nkcelectronics.com/wiznet-wiz812mj-tcpip-network-mod812.html Where I bought the Wiznet module
http://www.arduino.cc/en/Tutorial/TextString Libraries are there to make your lives easier
http://arduiniana.org/libraries/flash/ Thanks Mikal Hart for all your contributions
Dropboxed .pde of code I realized that the code wont necessarily work just by copy+paste, since there is embedded html in the pde. Use the scrollbox to view, and download the pde to run or modify.