Automotive history is littered with oddball features that flash into existence and then disappear again in short order. Recent decades have seen everything from Predator-like HVAC systems to plastic keys and Party Mode buttons. Volvo, though, is not one to be outdone when it comes to the kooky and strange. In the mid-2000s, the company proudly advertised a feature designed to detect murderers lurking in your car. We’re going to examine how that feature was sold to consumers, and how it worked in practice.
It sounds ridiculous, but that was the exact scenario chosen to advertise the 2007 Volvo S80. As Volvo’s top-of-the-range luxury car, it was loaded with equipment. One of the headline features was the optional Personal Car Communicator. At its heart, this was an upgraded keyfob, but the special sauce was in the car itself. The S80 featured a heartbeat sensor that could determine if a living being—human or animal—was hiding inside your car.
The TV advertisement for this feature relied on pure scare tactics. “Kate’s car is the last in a deserted lot,” reads a deep-voiced narrator. We see a woman in business attire walking to her car at night. The scene is set for danger.
Ridiculous Scenario
We’ll get to the engineering, but first—the ad. Kate approaches her car in the dead of night, but first, she pauses. She checks her keyfob. It flashes, red. A look of terror flashes on her face, and she stalks away from the Volvo, fleeing for her safety. “With the world’s first Personal Car Communicator with a heartbeat sensor, she can detect an intruder inside her car,” says the narrator. “Introducing the all-new Volvo S80. A luxury car that protects the luxury of life.”
So, pretty useful, right? You can press a button on your Personal Car Communicator (PCC) keyfob, and if two red lights start flashing, it’s because the heartbeat sensor picked up the presence of a person (or animal) in the vehicle. You’re about to be carjacked or murdered or something, so you should definitely not get in your car.
I want to state here that I’m all for features that make cars safer. But the way Volvo marketed this was kind of sensational, and it preys on tropes of women’s safety that feel unseemly to leverage for commercial purposes.
In any case, I have a few questions about this feature. Does any of this make sense? Let’s dive into the S80’s manual to learn more, first.
The heartbeat sensor appeared not only in the S80, but in the third-generation XC70 too, and other late-2000s Volvos using the PCC keyfob. It worked the same way across the board. To check the heartbeat sensor as you’re walking to your car, you hit the “Information” button on the keyfob. While locking and unlocking only works at a range of 65 feet (20 m), the Information button can be used to query the car’s status at a range of up to 328 feet (100 m). If it contacts the car, the lights will dance around on the fob for a few seconds. Then, the fob will display a solid green light if the car is locked and all is well. It will display solid yellow if you’ve left it unlocked, or a solid red light if the alarm has been triggered. Scariest of all, you’ll see two flashing red lights if the heartbeat sensor detects someone in the vehicle. Notably, this warning is only available if the alarm has been triggered.
Basically, somebody has to have broken into your car and triggered your alarm before the heartbeat sensor is even useful. I imagine if my car was telling me the alarm had gone off, I’d be pretty wary on the approach anyway. At the same time, I guess there’s some value in knowing that there’s someone still in it, which might prompt me to further keep my distance. Fundamentally, though, it feels like a real edge case.
One wonders if instead, the real value is as a peace-of-mind feature. If you’re walking to your car in a dark lot, you can hit the button and get a green light. This provides some reassurance that the car is still locked and there probably isn’t anyone hiding inside.
Even still, it does nothing to protect you against someone hiding just outside your vehicle, waiting to strike. There’s also the fact that the heartbeat sensor is conditional on alarm activation. In what weird situation does someone break into a car, and then sit in the back while the alarm is going off, waiting for the owner to come back?
There’s also a pitfall to avoid in the user interface, too. The driver needs to be wary of activating the Information button too far from the vehicle. In this case, the lights won’t dance around the fob; it will merely jump straight to showing the car’s status as last stored in the fob’s memory. If you weren’t paying attention, you could trigger the fob out of range, see a green light, then walk straight into a dangerous situation not realizing your folly.
How It Worked
The Volvo heartbeat sensor stemmed from earlier research with Ford, undertaken when the Blue Oval owned the Swedish concern. Ford announced the technology in 2001, years before it was ever available on a production car. It was quite literally inspired by security measures used at nuclear facilities. In Ford’s words:
SecureCar’s heartbeat sensing technology was developed as an offshoot of a security system developed by a national laboratory to protect nuclear power plants. In that application, security officers set up a station at the plant entrance. There, they attached two sensors called geophones to every vehicle entering or leaving the lab grounds. The geophones measured sounds in the vehicle structure, and software in a portable computer analyzed them to determine whether the vibrations matched the patterns of a human heartbeat. No matter how big the vehicle, these heart pulses set up a distinctive vibration that the sensitive geophones were able to detect.
To apply this in an automotive context, Ford used the same techniques but with more suitable hardware. A small “micro-accelerometer” was installed in a Volvo S80 test vehicle, which had the sensitivity to detect the presence of a human heartbeat inside the car. According to Ford, it could even detect “someone simply touching the outer skin of the body.”
The idea was that through incredibly advanced signal processing techniques, the telltale vibrations of a human heartbeat could be detected and filtered out from any other minor vibrations that may be picked up from the environment. Of course, given the system was designed to operate when the vehicle is at rest, there were no concerns around interference from engine vibrations or the like. However, Volvo would note in its user manuals that the system may be disturbed under some conditions.
The HBS detects an individual’s heartbeat that is transmitted to the car’s bodywork. For this reason the function of the HBS can be disturbed in an environment subject to noise and vibration.
-Volvo S80 owner’s manual, 2007
Normal resting human heart rates typically sit around 50 to 100 beats per minute. Thus, Volvo’s engineers would have designed a signal processing algorithm to hunt for regular simple pulses fitting that rhythm. Faster heartbeats may have been considered too, just in case your prospective car thief had run a 5K and was pumping away at 180 BPM or something. The resting heartbeat range is slower than most popular music, though, which would help avoid confusion for Volvo’s heartbeat sensor. At the same time, though, one wonders if your car alarm was triggered, and there was a music festival in the distance… could the distant pulse of a kick drum at 100 BPM set off the heartbeat sensor? Park your S80 somewhere near Lollapalooza this year and maybe you’ll find out.
Fundamentally, though, the S80’s heartbeat sensor was fairly straightforward. It was an accelerometer stiffly attached to the vehicle’s chassis, intended to detect human heartbeats that were conducted through the car’s body.
I’d love to cut open one of Volvo’s heartbeat sensors, but I wasn’t able to source one from a local junkyard. They’re available online for anywhere from $45 to $200 depending on where you look. If we look at the external housing, we can infer one main thing. Note the two large metal mounting lugs. These are intended to couple the sensor very firmly to the chassis of the vehicle. This is to allow it to readily pick up even the tiniest vibrations being conducted through the body shell. This is important, as the vibrations of an occupant’s heartbeat are slight and likely passing through quite a bit of soft seating material prior to reaching the steel body of the vehicle.
By coupling the accelerometer firmly to the vehicle, it has the best possible chance of picking up tiny vibrations. This is akin to how we use a contact stethoscope to listen to human heartbeats, or like putting your ear on to a railway track to hear the approach of a distant train. Solid materials conduct vibrations well, so it makes sense that the heartbeat sensor would be coupled as firmly and directly as possible to the chassis.
In any case, if we cut the sensor open, I doubt there’d be much to see. Inside, we’d most likely find a MEMS accelerometer, where MEMS stands for microelectronic mechancial system. These are accelerometers that measure acceleration using tiny mechanical structures etched inside an integrated circuit. Without the tooling to etch away a chip and image what’s inside, you won’t see much. This video from Bosch explains their operation:
In a MEMS accelerometer, a small “proof mass” inside the chip moves in response to motion or vibration. As this proof mass moves, it creates a change in capacitance inside the chip which can be detected by the supporting electronics inside. If you know the weight of the proof mass and how it’s damped, and you can measure its motion precisely via capacitance changes, you can calculate the acceleration of the accelerometer. Or, you can measure the fine vibrations passing through it, which are accelerating the proof mass.
It’s possible, of course, that Volvo used another kind of accelerometer, but the basic principles are the same. A moving mass in the accelerometer is accelerated by motion, and its movement is accurately detected. By knowing the precise mass involved it’s possible to determine acceleration accurately. There are a great many types of accelerometers out there, but these days, MEMS accelerometers are the most popular. This is because they are a small, cheap electronic chip that can be chucked into almost any product you can imagine. They usually pack multiple accelerometers in multiple axes to detect motion in multiple dimensions. They’re packed into every smartphone and virtually every car these days, detecting motion, serving as crash sensors, and doing all kinds of other useful jobs, too.
Bigger Dreams
Interestingly, the SecureCar Heartbeat Sensor that Ford touted in 2001 was intended to serve higher purposes. In addition to detecting intruders, the prime focus was to avoid the tragedy of parents accidentally leaving a child locked inside a hot car. The idea was that if a heartbeat was detected inside the vehicle shortly after it was locked, the alarm would be sounded to raise the alarm of an abandoned child. It would work on dogs or cats, too, according to Ford at the time.
Volvo didn’t implement this functionality, however. It’s easy to understand why, given the way Ford first described the technology. Parents often leave children sitting in the car in cooler weather when they’re of the appropriate age for doing so. Having the alarm go off every time you walk away from the vehicle in such a situation would be incredibly frustrating and confusing to most users. Rear seat warning systems of other types have since become popular, anyway. Automakers often have the dashboard flash a “CHECK REAR SEATS” warning if the vehicle detects the rear doors being opened at the start of a journey. Alternatively, radar presence sensors or seat weight sensors have been used for this purpose.
In Ford’s early research efforts, the heartbeat sensor was also paired with a CO2 sensor which could detect respiration in the trunk, automatically opening it or sounding an alarm if someone was detected inside. There was also a capacitive touchpad inside the trunk of the research vehicle, which would unlatch the trunk if someone brushed against it.
Volvo also had other neat ideas prior to the launch of the 2007 S80. In 2003, it touted the idea of the Volvo Personal Communicator (VPC), an obvious predecessor to the PCC. The concept featured much of the same functionality as the PCC keyfob, but could also read fingerprints for positive driver ID. It also featured cellular communication for talking to the car at greater distances and previewed the idea of entering the car by simply grasping the door handle, with the fob handling access control wirelessly.
Lost To Time
Ultimately, the heartbeat sensor didn’t stick around. Maybe it was the limited use case, maybe it was the advert that showed a woman fleeing from her Volvo S80. Either way, the concept didn’t really seem to excite anyone and it was eventually dropped from Volvo’s lineup.
I can definitely understand being a little wary of getting into your car after you’ve left it somewhere questionable. At the same time, if the car’s already got an alarm, it’s hard to see the heartbeat sensor doing much to help beyond that. In any case, it’s clear that Volvo’s engineers weren’t afraid to dream, and the bean counters were happy for them to fit some pretty nifty equipment to their cars in the late 2000s. Here’s to another innovative feature that the marketplace simply couldn’t support. Let me know your own favorites down below, and maybe I’ll do an engineering deep dive into those, too!
Image credits: Volvo, Bosch Sensortec via YouTube Screenshot, DigiKey, eBay
Interesting how these features are not often more interesting than what we had in the Japanese bubble era, yet being a less distant memory they seem more relevant?
Lots of weird things in the 2000’s, mostly limited by tech at the time. Eg the periscope like extension camera in the bumper of Toyota and then BMW, to see outside a blind T junction. Before we got all those 360 cameras, although I don’t think any of them serve this purpose
Tell me more about this camera! – lewin@TheAutopian.com
My 2001 X5 had a motion sensor in the overhead/headliner box/module thingy. I learned about this when I left my dog in the car to go into a store. I remember standing there thinking, “who’s the dumbass that set off their alarm.” It also had the super annoying, 90’s car alarm sound to go with it.
Also learned that leaving the windows open on a windy day would set the thing off. I ended up just disconnecting it.
That said, I could see this serving the same “lurker” alarm function lol.
Having just become the owner of a 2006 V50 whose fancy sensors seemingly decided to start going the moment the title traded hands, I feel personally attacked by this article about fancy Volvo sensors. Mine’s a base model, none of that heartbeat sensor nonsense, but the throttle position sensor and the fuel pressure sensor both went a couple days after I bought it, after my mechanic picked the car up to deal with a small steering issue the previous owner disclosed pre-sale.
Almost three weeks have passed since the car went into the shop; not only did the “small steering issue” turn out to be not so small, sensors started to fail while my mechanic worked on the car, so it hasn’t left the shop yet. Like I needed more validation of my firm conviction that electronic everything is a huge drawback. Sensors fail, then suddenly your mechanically sound, perfectly drivable car gets you stranded because the dumb computers under the hood got scared for no reason. And of course, sensors ain’t cheap.
Meanwhile, last year I drove about 1000km in the Quatrelle thinking I’d blown a carb gasket, having to choke it all the way for the engine to not die all the time, and putting off tearing into the carb; as it turns out, the two nuts securing the carb to the intake manifold had gotten loose and the carb was shaking in its mounts – the gasket was fine, it just really wasn’t gasketing anything. Literally fixed the issue in seconds by tightening 2 nuts, but most importantly, the car was forgiving and kept going at a time when I desperately needed to travel all those kilometers for work and could not afford to get stranded. Anything close to that in a modern car would’ve likely meant a festive light display in the dash and a few dozen error codes, not to mention immediately getting stranded because the dumb computers under the hood are drama queens and the tiniest little thing will make them pout.
But hey, I’m ready to be convinced I’m wrong. I picked a cheap, high mileage one (360,000km) fully conscious that it could be a gamble, but made sure it had been serviced recently, includuing the timing belt which has only 5,000km/less than a year on it – all servicing records verified by my mechanic. I’m hoping a few new sensors will allow it to prove itself reliable enough for a while at least. I’m ready to love this car, it’s a very cool design, it’s in excellent aesthetic condition, both inside and out, and it’s worlds apart from anything I ever owned in terms of creature comforts, safety, etc. It’s a proper family car that my family deserves, really hoping it doesn’t let us down.
Dogs are always setting off the alarm in my XC60, this is also handy to see if the person ziptied and gagged in the back seat is still alive
I had an XC70 with this feature. I never had any lurkers in the car, though.
Note to self… when stalking people in high end volvos that are locked and armed, hire a jackhammer guy to do his thing nearby to fuck up the sensor readings. Gotcha.
I think this feature is most useful for when someone is being stalked by their ex. The ex would have access to override the car alarm if they previously had access to the keys, and they would also be a dangerous person to have hiding in there.
Interesting angle. I wonder if you get in and lock the car… yeah, I could see that potentially working
From my reading, the heartbeat sensor works if the alarm HAS been triggered, but it does not necessarily still need to be going off. If someone is inside your car rifling around or waiting to ambush you, they probably killed the alarm after getting in. Or, it’s still useful if the alarm is going off because it can tell you if someone is in the car regardless of how the alarm was triggered. If someone broke in just moments ago, and is inside the car rifling around, you may not want to approach. But if they’ve already left or the alarm was triggered by something benign, you are fairly confident no one is inside.
The heartbeat sensor seems like a MUCH better option(or at least adjunct to) the radar-based options. Those are not very sensitive, having both would be great to help prevent a really tragic occurrence. It’s easy to solve for the older kid or adult problem, just give it an override. If you know someone’s sitting in the car, hit the lock button three times and it will be silenced or something like that. And then have a menu option to turn it off permanently if you don’t have any small living beings that could be left accidentally.
Seems a better use would be sense the heartbeat automatically when walking away from car to let driver know you forgot your baby in the car. Not sure why they don’t use technology at the border to detect illegal immigrants.
That would require spending dollars on the car to enable feel-good advertising, instead of just programming the dash to tell you to check the back seat every damn time you turn the car off, whether there’s someone back there or not, then declaring yourself Protector Of The Babies.
I’m glad you mentioned this was on other models, as I was going to note that. A family friend had this feature on her XC90 (maybe XC70? It’s been almost 20 years, my memory is hazy), and she found it a great peace of mind despite not at all understanding how it worked. She did note that weather would sometimes set it off, notably a close lightning/thunder strike, but then she would just check the interior of the car from the outside before getting in.
The PCC had to be one of this century’s notably expensive feature follies, but I think what came out of it was super clever. My ’12 XC70 doesn’t have the heartbeat sensor but it has a version of the PCC where the ‘i’ button still communicates with the car to tell you whether it’s locked or not. If it’s out of range then it just displays the last known signal sent to the car. Obviously nowadays that’s pretty outdated when you can lock and unlock most cars using an app, but I think it’s a clever and offline method to have that peace of mind as to whether you’ve locked the car.
I’ve always been curious how PCB-mounted accelerometers work. And since every PCB at work has one, this article is particularly relevant and I can charge my employer for the time spent reading this article. Thanks, Lewin!
😀
This, along with the new Dodge ‘vroom I’m a muscle car’ noise feature, should be added to the Changli.
Honestly, we should have a Torch Event where we mod the Changli with the most absurd things we can think of. Like we threw the modern equivalent of the JC Whitney catalog at it. Have to make sure it’s marketed as a No Chainsaw event.
And that thing that puts smells inside your car too
This thing ruined so many in-car surprise parties.
“the telltale vibrations of a human heartbeat” …
The Volvo shrieked, “dissemble no more! I admit the deed! –tear up the planks! –here, here! –it is the beating of his hideous heart!”
Thanks, Lewin!
A Poe attempt at humor.
Nevermore, please.
Quoth the raven, “Lock the door!”
Loved this Simpsons episode.
I’m surprised Chevrolet didn’t market this first as they were the heartbeat of America.
After groaning, I have to upvote this.
They didn’t wish to be detected.
Love how they refer to life as a luxury instead of, you know, a basic human need.
Other than that, screw the heartbeat sensor, give me the “yes, you really locked the car” check light. As somebody whose brain doesn’t brain right before the second cup of coffee I’ve found myself walking back to the car and double-checking way too often.
I wonder if they did Pink Floyd “Speak to Me/Breathe” testing? Seriously though, I had no idea this was a thing until my wife told me she checks the car every time. It really opened my eyes about the safety concerns others have that I never consider. This gets me thinking: key fob button to turn on all interior lights to a car for 5 seconds?
Edit: Ugh, two sips of coffee and I remember nearly all cars do this with the lock/unlock. Good morning!
The PCC has an illuminate button too that does exactly that. Useful, for sure.
So, this could let you know of a litter of kittens in your vehicle?
Run, don’t walk, run away!
Neat. They could probably do the same thing with the ultrasonic interior sensors built in to some cars today. The neatest part is the interactive keyfob though. I mean, I never see my fobs, they live in my sling, but it’s kind of a neat idea to have it display the status of the car. Even today where most cars have apps that can do all of that, it would be nice to be able to just look at the fob and say “oh good it’s locked” instead of having to pull out your phone, wait for an app to load, it doesn’t load, force close the app, open the app again, dismiss the changelog, dismiss the ad about service, then finally see if it’s locked.
I remember these ads!
Seemed like a weird feature at the time (does/did this happen a lot?) and it seems like the market agreed.
I’m guessing this scenario is extremely rare.
And YET. As an embarrassingly anxiety-ridden adult (who is only slightly less afraid of the dark than her 7-year-old), I always worry there is someone hiding in the back when I get into my car in the dark. I solved this “problem” with a little less tech by attaching a small flashlight to my keychain that I use to check the back before I get in. My initial thought when I saw the ad was, “Finally!” Followed swiftly by, “I can’t afford a new Volvo!”
This is kinda neat. Wonder if it could be utilized as some sort of health monitor, especially for elderly drivers or folks with heart conditions. Like the vehicle detects erratic heartbeat and sends a message to the operator, and/or could go into a “get to safety mode and call for help” semi-autonomous mode.
Too bad development didn’t continue….
“There’s an intruder in your car, but his EKG doesn’t look too good. Better call the paramedics….”
“The baddie’s EKG doesn’t look too good. If you can surprise him nice and good, he won’t be a problem anymore.”
You can just run up and slap the car door or trunk lid with an open hand. That used-to startle us every time when we were kids waiting in the car for people to return.