We are Ecurie Aix, the Formula Student team from the RWTH Aachen. We design and manufacture a fully electric race car to compete in Formula Student competitions against teams from other universities from around the world. For our electronics we design and use many different PCBs throughout the entire vehicle which are all kindly supported by AISLER. One such board is our own Data Logger which is presented in this article.
For our team, it is crucial to accurately record vehicle data during tests and races so that it can be analysed and evaluated afterwards. Whether for performance optimisation or troubleshooting, a reliable CAN logger is the central tool. That is why we developed our own logger, which is specifically tailored to our requirements in real-world vehicle use.
Compared to our previous model, the new CAN logger offers numerous improvements: it now supports five CAN buses instead of four, allowing it to capture even more vehicle information. The device focuses entirely on the essentials. We have deliberately omitted optional functions that are often found in universal industrial products but are rarely needed in specific applications. This has made the logger not only significantly more compact, but also considerably lighter: it now weighs only 100 g instead of 500 g!
For maximum reliability, we use state-of-the-art CAN controllers and transceivers. This ensures that not a single CAN frame is lost, even under high bus load – an essential prerequisite for accurate and complete logging.
A large capacitor at the 12V input also ensures that the logger continues to run for a few seconds even after the vehicle’s LV system has been switched off. This means that even the last frames, which are often particularly informative, are reliably recorded and stored. To prevent this capacitor from causing excessive currents when switched on and possibly tripping fuses, we have integrated an eFuse with a configurable slew rate. This ensures that the capacitor is discharged slowly and in a controlled manner, a small but crucial detail for stable operation.
We have also deliberately opted for robust and practical solutions for data export: instead of having to remove an SD card manually, data is transferred via an Ethernet interface. This enables fast, reliable access to the log data, without having to remove or open the device. This saves valuable time and reduces potential sources of error, especially in stressful operating environments such as racing events or test days.
Our new CAN logger is therefore not a universal device for all purposes, but a tailor-made solution for our vehicles: lightweight, robust, reliable and focused on the essentials. We are delighted to be using it in our vehicle tests and racing operations with immediate effect!
