Enhancing Suspension Performance: Suspension Tension Meter

In the world of motorsports and vehicle engineering, precise measurement and data collection play a crucial role in optimizing performance. One of the devices that allows us to measure such data is a Suspension Tension Meter. It’s a circuit designed to measure uniaxial forces acting on push-rods and transmit the collected data over the Controller Area Network (CAN) bus.

This PCB is a part of a larger-scale project undertaken by PUT Motorsport, the racing team associated with the Poznan University of Technology.

Since 2014, we have been continuously engaged in the design, manufacturing, and testing of racing cars. These cars undergo rigorous evaluation during international competitions, where teams from all over the world participate.

Lately, we were focused on developing and enhancing an autonomous car. A numerous design choices have been made throughout this process to optimize its performance and to make it adhere to the technical rules and regulations.

JLCPCB's commitment to excellence and dedication to innovation perfectly align with our team's goals and aspirations. As a leading PCB fabrication house, JLCPCB's support is invaluable in helping us achieve our objectives in the competitive world of motorsport.

Get to JLCPCB now -> https://jlcpcb.com/HAR

At its heart, this advanced circuit is built around the STM32L4 microcontroller unit (MCU), renowned for its efficiency and versatility in embedded systems. The STM32L4 MCU forms the brain of the operation, orchestrating the collection and transmission of critical suspension data.

What makes the Suspension Tension Meter precise is the use of the NAU7802 precision low-power 24-Bit Dual-Channel Analog-to-Digital Converter (ADC). This specialized IC is engineered to provide precise measurements from strain gauge sensors, ensuring that the forces acting on the push-rods are accurately and reliably recorded.

The key to the accuracy of this system lies in the high resolution and precision offered by the 24-bit ADC. It can capture even the slightest changes in tension with exceptional sensitivity, making it an invaluable tool for our engineers looking to fine-tune the suspension system.

As vehicles hurtle down the racetrack or navigate challenging terrains, the Suspension Tension Meter's ability to provide real-time data over the CAN bus opens up a world of possibilities. Having the telemetry data, we can use it to make adjustments to the suspension settings, optimizing the vehicle's handling and overall performance.

In the Suspension Tension Meter, the CAN interface serves as the backbone of data transfer, ensuring seamless communication between the circuit's STM32L4 MCU and other relevant components or systems within the vehicle. This integration allows real-time transmission of precise suspension data over the Controller Area Network. The CAN interface's deterministic and low-latency characteristics are essential in this context, enabling engineers and drivers to fine-tune the suspension settings in real time, enhancing the vehicle's handling and overall performance on the track.

The whole project including both the hardware, and the firmware is open source. The repository is available at PUT-Motorsport/PUTM_EV_SUSPENSION_TENSION_METER_2023.

Full Schematic:

PCB Layout

Now that we’ve got the PCB design, it’s time to order. For that, you just have to go to jlcpcb.com and click on the “Instant Quote” button.

You don’t have to worry about the settings here, because you can adjust everything in the new appeared tab.

JLCPCB is also a sponsor of this whole project (not only this PCB but all the PCBs in the car!). JLCPCB (Shenzhen JLC Electronics Co., Ltd.), is the largest PCB prototype enterprise in China and a high-tech manufacturer specializing in quick PCB prototype and small-batch PCB production. You can order a minimum of 5 PCBs for just $2 (2 layers), just enough to have a few test/spare ones. To get the PCB manufactured, just upload zipped Gerber files.

Then, you have multiple options to adjust the number of layers to your PCB color. Every option here is very clearly marked and described (when you hover over the question mark).

After making sure your PCB looks good – by clicking Gerber Viewer, you can now place the order at a reasonable price. In the case of this project, there is 2$ for 5, 2-layer PCBs and it’s only 3-4 days build time(the time is extended due to the chosen color). To place the order, click on the “SAVE TO CART” button. Fast and cheap, right?

The quality is always really satisfying so I sincerely recommend JLCPCB.

The final product of this project.