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Introduction to OBD

Ashwiniks560 edited this page Mar 16, 2020 · 1 revision

Acquisition and Analysis of OBD data

Introduction to OBD

Studying and observing real-time parameters of a car such as rpm and speed can be a tedious task. This is made simple with the introduction of On-board Diagnostics (OBD). An OBD module is a simple port attachable device that records real time data from cars.

OBD was originally a computer-based system developed to reduce emissions by monitoring and analysing the performance of engine components. It has become an important tool in the automotive world as it is being used to diagnose mechanical problems efficiently.

A basic OBD module would contains an ECU (Electronic control unit), that accepts input from a number of sensors in the vehicle and controls the actuators. There are 2 versions of OBD:

  • OBDI
  • OBDII

How to use the OBD module?

1. Find a place to plug it in.

Most of the cars that are manufactured after the year 2000 would have the OBD port. It is usually located under the dashboard, beneath the steering wheel.

Issues faced: Locating the OBD port isn’t as easy as it sounds. It might be located elsewhere in a different model of a car. There are various video tutorials on the internet that guide us to where the port is placed by car manufacturers.

2. Check if the car supports the ELM protocol.

Cars that have been manufactured before the year of 2007-2008 support a different OBD protocol. This can be a major issue if the latest OBD module has to be used with an old car.

Issues faced: The ELM327 module that I purchased did not support the protocol that an Alto 2004 model could offer. Without an option, I had to switch to an XUV 500 (2013 model) for the project.

3. Connect a smartphone to the OBD module through Bluetooth.

The ELM327 module supports Bluetooth through which data can be acquired. The device has to be paired in order to give access to any data logging application that has to be utilised from a smartphone.

Issues faced: Pairing Bluetooth devices through a smartphone is not really a huge task today. But we should ensure that the OBD module stays paired throughout the data collecting session. If the module is not able to pair with the smart-phone please refer to the manual given with the ELM module or reset your Bluetooth settings on your phone. In the worst-case scenario, the module might be faulty and might need a replacement.

4. Find an application that supports the OBD module

There are a number of applications that can be used to obtain data from car sensors. As an activity I have narrowed down to a few applications that are available on the App store and well as the Play store. Here are a few apps: • Torque Pro (Link – Torque) • Car Scanner ELM OBD2 (Link – Car scanner) • BlueDriver OBD2 Scan Tool (Link – BlueDriver)

Issues faced: Although there are a number of user-friendly applications that can be used for the OBD module, the type of data that a person might need decides the application they would want to use. For instance, if a person just wishes to know if his/her car is in a good condition he/she can use just the basic OBD application needed just for the job. But if he/she wants to analyse the data and use it for research the basic application might not help. In my opinion, the Torque Pro is the best application available in the market that can be used for development as well as research purposes.