CAN to Sensor Interface

DESCRIPTION

     CSI (CAN to Sensor Interface) Implementation and Testing for GFR18c, the 2018 Formula SAE combustion car developed by Global Formula Racing (GFR). The purpose of this project is to replace the devices that currently convert raw sensor readings into the CAN bus compatible data that other devices on the CAN bus can read. The devices currently used for this task are two MoTeC VIMs, which are both heavy and expensive. The two VIMs will be replaced with at least CSIs, which can be placed relatively close to sensors, effectively reducing the length of analog wires in the car, and in effect reducing interference and clutter. The purpose of this document is cover all of the technical aspects of the CSI system such as the overview of the CSI system, a project timeline, engineering requirements, testing procedures and results, a methodology review and selection, illustrated block diagrams with interface definitions, design schematics, and a revision history respectively. This document will provide updates on the project status to GFR and technical managers throughout the development cycle.

TECHNICAL DETAILS

Controller Area Network (CAN) busses are becoming increasingly common in modern cars as a method for vehicle electronics to communicate. The CAN protocol uses just two wires that carry differential voltages to communicate at up to 1 Mbps. Differential voltages provide strong data integrity. Electronics connected through a CAN bus can communicate with each other directly, without the need for data to go through a central computer for processing or distribution.  The need to communicate information using the CAN has become increasingly important as cars become more complex and contain more computers and sensors.

The purpose of the GFR18c CAN to Sensor Interface (CSI) project is to adapt the CSI that was developed by German GFR members at DHBW Ravensburg for the GFR 2017 electric car (GFR17e) to work with the GFR 2018 combustion car (GFR18c). The 2017 combustion car contained two MoTeC VIMs, which were connected to over 60 sensors combined. They receive raw sensor data and convert it into the CAN bus protocol so that dataloggers can store the sensor readings. VIMs are both heavy and expensive, and since there are only two connecting to many sensors in the car, there are a lot of long wires running through the car. The CSIs for GFR18c connect up to six analog sensors, one digital PFM sensor, and an I2C bus. They can convert the readings to physical values using stored sensor calibration data before pushing the data onto the CAN bus. The CSI is lighter and cheaper than the MoTeC VIMs, but there will be many more of them, allowing closer placement to sensors, and in effect reducing the length of wires. Analog data is susceptible to interference, and reducing wire length will reduce distortion of the sensor data.

Words to PCBWay

I am a member of the Global Formula Racing Team. We are an international student racing team with members from the American Oregon State University in Corvallis and the German Baden-Württemberg Cooperative State University in Ravensburg. Every year students design and build two very successful race cars; one combustion and one electric car. Each year we enter our cars in Formula Student races across North America and Europe, in which teams from more than 500 Universities participate. This year we are also developing a driverless car. 

We had a very successful 2018 season, with our combustion car reaching second place in the FSS race in Barcelona. On the Hockenheimring (Germany) we were also able to reach fourth place. The electric car won second place at the FS Italy and the fifth place in Barcelona and achieved the best electric car result in the history of the GFR. These achievements are only possible through the support of our sponsors.

In this new season, we are looking for support from sponsors new and old. PCBWAY could help us very much with PCB assembly of our project  CSI which stand for CAN to sensor interface, which we need PCB assembly because our car needs to be lightweight and reliable, and we cannot assemble competitive boards ourselves.

We offer our sponsors a wide range of global promotional opportunities. For example sponsors will be able to interact with the thousands of future engineers and business professionals that the Formula Student teams are made up of. We also have a large following on social media. As a sponsor of the team we will link your company on our website, publish social media posts thanking and mentioning your company, and depending on your sponsorship amount, display your company's logo on our car.