Join me for a small tour into the fascinating world of automotive HMIs and understand how they make living in our third space more convenient.

Ever since I can remember, anything that has wheels has always fascinated me. When I was a kid, I remember being obsessed with one of my relative’s flour-grinding machine that had pretty cool wheels; I used to move it around in their front yard, embarrassing my parents. That said, you can only imagine how excited I was when I was offered the opportunity to work on an automotive HMI project.

I’ve been working on HMIs for over 4 years now, and needless to say, every single project I’ve worked on so far has given me a good amount of career satisfaction. The projects I’ve worked on include a mix of big-name clients and internal products, so I’ll be maintaining confidentiality while talking about the subject in general.

What is an automotive HMI anyway?

I think the best way for a beginner to understand what an automotive HMI is, is to think of it as an extension of your smartphone. And I say that because most of the new cars today come with a smartphone app that allows you to stay connected with your car.

With that app, you can do a number of things including locking/unlocking, starting the car, turning on the AC, opening the sunroof, monitoring the health of the car, and in some cars, you can remotely park the car via the app or even ask the car to come towards you.

Some HMIs also offer built-in Amazon Alexa connectivity so that you can simply ask Alexa to lock or unlock the car from your home, for example. But anyway, in the automotive sector, the Human-Machine Interface, or HMIs for short, mainly refers to the displays you’ll find in a car’s dashboard and how the user interacts with them.

And a lot of these HMIs allow you to create multiple user profiles — which as mentioned earlier, make them almost an extension of your smartphone. The owner of the car, for example, can have their own settings for seat, temperature and steering, and likewise, the owner’s partner or a friend can have their own settings. All they need to do is to log-in to their profile and the system does the rest automatically.

The HMIs come in all different sizes, and in some cases in different shapes — depending on the price and/or the segment of the car. And this is one of the key differences between working on something like a mobile app or a dashboard and working on an automotive HMI. You’ve to deal with different sizes and aspect ratios — depending on the car you’re working on.

A budget hatchback these days, for example, offers an ordinary 7- or 8-inch touchscreen, and as you go towards the higher segment, you get larger, high-resolution ones. Further up the price range, the carmaker will include a fully digital cluster — in addition to a touchscreen, and some carmakers will go bonkers — in the luxury segment by filling the entire dashboard with displays — this includes a passenger display — just to keep the front passenger entertained.

The idea of a passenger display actually came from sports cars where they mainly displayed rev counters and other performance-related information. In the new BMW 7 Series, there’s even a display incorporated into the doors — for seats and climate control.

A lot of carmakers in the luxury segment are getting rid of physical controls in favor of displays and touch panels — which I’m not a huge fan of, but that is the direction these guys are going.

So, when we are working on the user experience of an automotive HMI, we need to take all these displays into consideration — because you have the responsibility to keep all the passengers entertained and comfy while simultaneously keeping the driver informed and focused on the road, right?

What does that mean? Well, consider this: some of the information from the touchscreen also needs to be displayed in the cluster. Examples include incoming call information, current media playing information, and of course, navigation.

Why do we do this? Why do we show the same information on the cluster? Why showing only on the touchscreen isn’t enough? In case it is not already obvious to some of you, the reason we do that is simply to prevent the driver from getting distracted. You want the driver to be focused on the road as much as possible, and so, you need to copy-paste some important information also into the cluster.

You might be asking — not all cars come with a full digital cluster, and you’re right, not all cars come with a full digital cluster, but most cars come with this tiny li’l display in between the gauges — which reiterates what I said before that when you’re working on an automotive HMI, you to deal with different sizes and aspect ratios.

If you guys are still with me, I also wanted to quickly touch on the topic of branding and icons — which obviously varies from one brand to another. Kia for example, uses its own fonts and icons, likewise, Hyundai’s font and icons vary. Ford has its own theme going on, and the same is true with Polestar — powered by Android OS. These are just a few examples, but you get the idea, right?

However, there are some icons that are standard across the industry. These global icons are not gonna change regardless of the carmaker or the car. We call these tell-tales. If you have a car, I’m sure you recognize some of these, right? The other day, one of my good friends was asking me, this engine icon looks like a helicopter, why can’t we change it?

Well, think of these icons as letters of a language, right? You can’t change the shape of a letter, because those letters have been associated with that language for a long time, right? The same applies to these tell-tales. These tell-tales have been used ever since the display technology was introduced into the cars.

And so, one of the key advantages of working on an HMI project is that when it comes to these tell-tale icons, you don’t have to create them again and again, you can simply re-use them from your automotive components library.

Another thing I quickly wanted to cover is the driving modes and how we display them. Some of you might have cars or two-wheelers that offer different driving modes. In a luxury car, for example, you may see modes such as Eco, City, Sport and Sport+. And, the way we visually differentiate them is with colors. The Eco mode, for example, will have a green theme and Sport or Sport+ will have a red theme. Some of you may have this question as to why we use red. Red is something normally associated with danger or an error.

To answer that question, you need to have an idea of what these modes actually are. Let’s take these four modes as an example, and City is gonna be the default mode. Let’s say your car has 500 horsepower, you’ll not get all those 500 horses in the City mode, you’ll get those only in the Sport+ mode. There are a few more things that also happen in this Sport+ mode, such as stiffening of the suspension and a change in steering ratio — to make the car feel more sporty. So, the color red in this case doesn’t indicate an error or a fault but aggression. The Sport+ is the most aggressive setting designed to offer a sporty driving experience.

The same principles apply to Eco mode — this mode is designed to offer a gentle driving experience and save fuel as you cruise along the highway or just pottering around the town. This mode doesn’t give you all 500 horses because it is about being as efficient as possible, and therefore it will have a green theme.

I guess I’m gonna stop here because as the title says, this is just “a glimpse” into the world of automotive HMIs. But I genuinely hope you enjoyed everything that I had to share. And speaking of sharing, please do share the article with your friends who might be interested in the topic.