Finished the PCB layout and submitted to Gabe and Shwetak for approval. -Ben (5/12/10)

Made corrections to PCB layout per suggestions from Gabe and the Advanced Circuits DFM checker. -Ben (5/13/10)

Ordered PCB from Advanced Circuits ( It should be arriving around the end of next week. I also placed the order for the surface mount components. -Ben (5/14/10)

An early version of the web portal is up now at

It can register users, retrieve their data, and display their OBD data in a table format. One questionable design decision was to disallow users with the same username, even if they had different passwords. Other issues are a lack of informing the user when something goes wrong (eg. the app fails silently and returns to the sign in page if the user mistyped their username or password). There are also some security concerns. This app uses cookies heavily as authentication. However it does at least minimize the use of URL parameters.

Further, miscellaneous notes: the user database gets cleared when a GET request is sent to vaytahome. This was useful for debugging purposes, and I just forgot to take it out. Will be fixed on the next upload. There is not yet a way to accept new Trip or VaytaPoint data. This will require coordination with David on the Android app end. I also kind of want to refactor the web page names. They are not nearly as a descriptive as I thought they would be. I have applied for and received a Google Maps API key. So the next steps are to devise a mechanism to upload data from the Android app, and to display data, not as a table, but superimposed on top of a Google Map. -Brent

This week on the android app, I worked on implementing a database on the phone that would store data before being sent to the web app. I also worked on setting up the ftp app that can be used to upload data to the web. In the database, all the different metrics we are collecting can be stored, and useful queries can be done to retrieve data stored in the database. I have also made made it possible to dump each trip stored in the database to XML files that will be used sent to the web app. to send the xml files, I am using another android app called AndFTP that allows me to upload files to an remote FTP server. Future work will include compressing the xml files before they are sent, and displaying live data in a useful format on the phone. -David

Programming of the MCU and ELM communication has run into some issues. The ELM chip occasionally returns errors. The reason for these errors are uncertain so far, but error handling routine will need to be written up. The majority of my week was discovering the reason behind issues with the memory module. Some "non-determinism" allowed tests to succeed before but not now. Apparently the memory module only receives commands some of the time. For example, sending a write enable at startup only succeeded during 12 out of 20 startups. If the commands themselves are the only issue, then it should be fixable. However, if data doesn't go through correctly, there may be a significant problem. I'll continue to work on these errors next week. - Chris