Arduino in Motorsports

Let’s just start by saying, that while I professionally build vehicles for Motorsports, including chassis, engine, and electrical, the fine electronics side of things have always baffled me. I am attempting to branch out on my personal project to expand my knowledge and potentially use this on future customer builds if and once perfected.

I bought a Amazon special knockoff board with a starter kit a few months back to start playing around the Arduino. I built myself a new sequential shift controller for my sim racer, that also controlled multiple vibrating motors to simulate road and engine feel. I’d love to take credit for doing this, but I relied heavily on forums, diy’s and a program called SimHub.

Lately, however, I’ve been brainstorming the feasibility of using an Arduino with a display to give temperature and pressure readouts based on sensors installed on my engine. Water temp, oil temp, oil pressure, etc. These are all resistance based sensors that are grounded by the chassis/engine block. I would also like to have an output based on water temp and another based on oil temp to trigger a relay for electric fans.

I am confident in the 12v wiring side of things and have attached a quick sketch on how I imagine it being hooked up. However, I’m not sure what the limitations of the board are and, quite frankly, I’m not sure where to start with coding. I’m sure I need to determine the resistance of each sensor at the given temperature or pressure that I want the fans to come on, and creating an output for the fan based on that. I would also need to create a table with voltage/resistances to convert into a temperature or pressure reading for the display.

Aftermarket gauges and fan controllers are nothing new on the market, however I have yet to find a programmable product that can both display sensor readings as well as control fans. A product like this would allow for more control of the systems at hand, as well as others I have yet to think of.

I have the sensors and an UNO from my shifter project to get started with. I have a display from the starter kit I ordered I’d like to use. These don’t need to be final components, but I would like to keep my initial investment low until I know it will or will not work.

It would also be interesting to hear what you guys think Arduino (or similar) could be used for in Motorsports.

No problem to make that system work. The difficult part is to select sensors that survive both the climate and the environment. Also Think about work done by Mr Handy, the Do-it-yourself-guy out there.
I ran a Z80 based singleboard computer in my car for ten years, 20-30 years ago. So, yes, make a rigid build and You've got something good.

Image from Original Post so we don't have to download it. See this Simple Image Posting Guide


Another important subject I Think about is noice supression by using both suitable sensors and the cabeling. Maybe shielded cables, terminating resistors etc. is Worth thinking about.

These are all resistance based sensors that are grounded by the chassis/engine block.

I assume you are talking about sensors that are only feeding data to the Arduino. If the sensors are already part of the standard vehicle control system then the easiest thing would be to get data from the vehicle’s electronic bus.

Assuming they are only for the Arduino then the resistance sensors should be wired with a suitable fixed resistor to make a voltage divider. Then the Arduino’s analog inputs can measure the voltage. Be sure to choose a resistor value that ensures that the voltage at the Arduino pin never exceeds 5v, even if the vehicle voltage rises momentarily to 15v or 16v.

If the sensor is connected to GND then the other end of the fixed resistor should be connected to the vehicle’s 12v supply.

Start by experimenting with a single sensor - maybe a water temperature sensor in a saucepan of water on the stove. Get an accurate thermometer for calibration. I have a cheap multimeter that came with a thermocouple attachment.


We've inventoried sensors for these type of systems for a while, the difference has been they have each been used for individual gauge readouts. The sensors we use are AEM of GM based. The wiring from each sensor is individually shielded with a braided loom.

I apologize for missing the image upload guidelines. Thanks for CMA there Robin2! I will be doing some research on voltage dividers. I definitely like and will do some testing with a single sensor and a heat source. Things always seem to work out when I just dive in and start learning. This should be fun!

As far as the 5v, should I maintain a 12v/battery voltage (as you said typically 13.7 to 14.9 v when operating in my instance) to the arduino or should I provide it with just a 5v constant?

Having a 12 - 20, 30? buck converter producing 5 volt can be good.
Remebering the last alternator crash, when the charge controller died and sent all voltage the generator had, the headlights almost X-rayed the trees…. It would be sad to burn down the Arduino world in such cases.

You might also want to browse around the Speeduino forum. The GPIO branch might be close to what you want to play with.

As far as the 5v, should I maintain a 12v/battery voltage (as you said typically 13.7 to 14.9 v when operating in my instance) to the arduino or should I provide it with just a 5v constant?

Car electrical systems can be very noisy. If it was my project I would provide a regulated 5v supply to the Arduino 5v pin. I think I would be perfectly content with a simple 7805 voltage regulator. I doubt if the inefficiency will be noticed in a car system.


Yes. The old, how old?, 7805 tolerates quite some voltage probably handling most alternator mishaps, so why not?

I'd consider preconditioning the input to the Uno with something like this:

The LDO on the Uno board is pretty good already. This provides a high-efficiency, conditioned 6.5V from 8V to 32V and has EMC compliance to EN61000-4-2..6,8 so it's reasonably well suited to an automotive environment. Keep it under 85oC and you'd be good to go.