The Truckputer

An inquiry into OBD-II values.

My truck has a GM 6.5 turbodiesel, but doesn’t have a turbo gauge on the dash. I wanted to monitor my turbo and make sure it was operating correctly so I put this together to read the boost pressure from the ECU using the truck’s OBD-II interface.

I had been running a ScanGauge II in my truck for several years, but I wanted some features that it didn’t provide. Using a smartphone or tablet I knew I could display more information and have additional features, such as auto-brightness, high resolution color, and a touchscreen.

I wrote software that runs on a Raspberry Pi that pulls live data from the truck via an OBD-II Bluetooth reader and allows any wifi capable device to load a webpage which shows that data. At the same time all of this data, along with current GPS position read from a GPS USB dongle, is logged to a database for later analysis. My goal is to display this information the way that Strava displays workout data on a map. This will allow me to create a visualization of things such as engine coolant temperature in relation to a mountain pass climb/descent.

OBD-II has been around since 1996 and I knew there was support for it in just about any programming language. One of the most full featured and stable libraries I came across was python-OBD. I wrote a Python script that watches for the truck to start then begins reading OBD-II data and storing it into memcached and PostgreSQL.

I didn’t want to write a native iPhone application. This was development overhead I didn’t need and I wanted the data to be viewed by any device with a web browser, including Android phones and laptops. So I wrote a simple olde timey AJAX based web page that polls for new data. The Tomcat web server is running on the Raspberry Pi. I wrote a servlet that keeps reading the values out of memcached and serves them as a small JSON file to the web browser.

If you’d like to talk about how I could help you with your own business or home projects please send me an email.