CAN Bus Sniffer Software and Hardware Options

The Controller Area Network (CAN) is a data communications bus common in cars. Simply refered to as the CAN bus it is used to connect an Electronic Control Unit (ECU) to other ECUs. The CAN bus and the interconnected ECUs are called an in-vehicle network (IVN). The data flowing on the CAN bus can be monitored. A CAN tool is connected to the CAN bus, then software running on a laptop or personal computer (PC) sniffs the data. The data is then displayed on the PC screen. Many CAN sniffers also support data logging and data injection for additional analysis. The CAN bus will be found in other types of transportation, from motorbikes to ships,

Note, that a CAN sniffer is different from a dedicated scan tool. A scan tool is used to read fault codes from vehicle ECUs. It is also called a diagnostic scan tool or fault code reader. It hides the raw CAN data used to read the fault codes. A scan tool only uses specific types of CAN data to obtain the fault codes and displays them in a friendly way. However, a CAN sniffer will show the CAN data at a low level.

Connecting a PC to a CAN Bus, Car or Other Vehicle

To connect a laptop or PC to a CAN bus the most common method, probably 99.9% of the time, is via a USB to CAN adapter. These come in three different styles:

• A CAN adapter that appears as a RS232 serial port via USB (including wirelessly via Bluetooth).
• A CAN adapter that converts directly to USB.
• A CAN interface that connects to the PC but has extra functionality, e.g. provides additional measuring functions beyond just CAN capture. This is normal specialised hardware connected to the PC via a USB cable or other interface.

RS232 Serial Port USB Adapter

Advantages: Low cost, easy interfacing Disadvantages: Low speed, restricted functionality

Example suppliers:

• CAN232 by LAWICEL AB
• Assorted ELM237 Dongles (using both genuine and fake ELM electronics microcontrollers)

Direct to USB Adapter

Example suppliers:

• CANUSB by LAWICEL AB
• [USBtin](http://www.fischl.de/usbtin/

Advantages: High speed, full CAN monitoring Disadvantages: May require custom PC drivers, can require custom software

Specialise Hardware

Advantages: High speed, extra functionality (e.g. CAN simulation) Disadvantages: High cost, requires specialised software packages

CAN Sniffing Software

This article provides a list of CAN bus sniffer software packages. Open source and pro software are in the list. Some of the professional software is free but will only work with a certain tool that needs to be purchased. Obviously the open source CAN software is free but support may not be readily available.

List of CAN Bus Sniffer Software Packages

www.mhs-elektronik.de

https://github.com/MHS-Elektronik