Purdue Formula SAE: CRAM and WHAM

Purdue Formula SAE: Who we are

Ever since 1992, Purdue FSAE has raced towards the checkered flag with one goal in mind: to gain valuable knowledge and experience through one of the toughest student design competitions in the world, and successfully transfer that knowledge to future generations of engineers at Purdue University. Each year, we build a new Formula One style open-wheel race car from the ground-up, and compete with hundreds of other schools and engineers around the world. Our team has placed consistently in the top tens among more than a hundred teams for the past three years, and we are aiming for first place overall with this year's car, the PF24. While this year's car is still under development and fabrication, here is a quick video showing our awesome contender for last season, the PF23.

Our team's incredible team of engineers work tirelessly day and night to ensure we meet our targets each year, and one of our main targets for this year is measuring suspension stress via strain gauges. Our goal is to precisely measure how forces act on our suspension rods on all four corners of our car, and to use that data to validate switching over to carbon fiber suspension rods for next year's car. With more and more focus being put on data acquisition and electromechanical control systems, the importance of PCBs has grown only larger in our increasingly complex race car.

Our project: CRAM and WHAM

After countless sleepless nights and more cans of Red Bull than we can count, we finally have a product ready for deployment: CRAM, and WHAM. CRAM, short for Compact Rapid Acquisition Machine, is an advanced 4-layer PCB based around the STM32F407 microcontroller, which will be tasked with high speed, high precision strain gauge measurements and data logging over CAN.

Simple overview of CRAM Hardware

While CRAM was mainly designed to sample strain data and report over a CAN bus, it is so much more. It has multiple redundancies on board in case of failure, such as a micro-SD card slot and two 8MB RAM banks for high speed on-board data logging. Its robust power supply system provides both clean, reliable power and multiple layers of protection against shorts, reverse polarity, or overvoltage. It has critical comms lines broken out to connectors for interfacing with hundreds of compatible sensors, making CRAM truly future-proof. With its powerful STM32 processor and easily expandable form factor, CRAM is not just a simple PCB designed for a single task; it was designed to last for generations of future race cars, more than capable for whatever task is thrown at it.

Simple overview of WHAM Hardware

While CRAM takes care of the majority of our strain gauge measurements, another PCB, called WHAM, will generate clean, amplified strain gauge signals for the CRAM to read and compute. Short for WHeatstone bridge AMplifier, WHAM has a lot of technology packed into an incredibly small form factor.

It first takes input from the strain gauge, then amplifies it via a wheatstone bridge and a precision instrumentation amplifier. The PCB, while small, has proper decoupling capacitors and M3 screw compatible mounting holes for secure placement on any surface, even a suspension rod. Its width is barely wider than the suspension rod it mounts on, and its use of compact connectors allow us to make it easily removeable and replaceable without compromising on compactness. Its easily replaceable 0805 footprint components and through-hole socketed amplifier chip also allows us to easily repair damaged WHAM modules or improve their accuracy by adjusting the calibration resistor. Just like CRAM, WHAM is also designed to be future-proof by maximizing modularity and reliability.

CRAM and WHAM's mission doesn't end here; they will be used to teach new members how to solder, microcontroller systems design, firmware development, PCB design, and so much more. CRAM will also be tasked with measuring exhaust gas temperatures via the use of thermocouples, and WHAM will be used again next year once our car makes the bold switch over to carbon fiber suspension struts. As you can see, CRAM and WHAM are incredibly important not just to the current season and car, but to the future of our team as a whole.

How a sponsorship could help Purdue FSAE:

It is clear how ambitious Purdue FSAE is when it comes to tackling new challenges. However, as a completely student-led organization, it can be fiercely difficult gathering the money and resources to fund all projects. Every car we build sums up to around seventy thousand dollars, and it is only with the help of our generous sponsors that we can achieve this incredible goal. A sponsorship from PCBWay would help our team immensely, as we can then redirect our funds on trying bold new technologies, or improving our facilities to aid in the transfer of knowledge to our future team members. Even the smallest of help from PCBWay will pay dividends for our team's future.

On a more personal note, as a passionate electronics hobbyist, I have used PCBWay in the past for my hobby projects, which often involved precise drills and silkscreen printing. I have always been incredibly impressed with PCBWay's precision and quality, all at an extremely affordable cost. It is my great experience with PCBWay in the past that gives me the confidence to use PCBWay as Purdue Formula SAE's manufacturer of custom electronics, as I know they will never fail when it comes to designing precision electronics for students and hobbyists, just like me.

The current sad reality is that our team is often hampered by budget, not ideas. With PCBWay's help, our team's only limit will be our imagination. PCBWay's support will help our team immensely in reaching our future goals, and inspiring the next generation of engineers to participate in what most of us consider one of our proudest achievement in our lives.