While the Citroën logo they project onto the pavement looks great, [OrangeTungsten] wasn’t thrilled with how their door-mounted projectors actually functioned. The mechanism for detecting when they should kick on was a bit too clever for its own good, and needed to be simplified a bit. Luckily for us, the process was meticulously documented for anyone else who might find themselves in a similar situation.
Originally, the projector detected when it should turn on by sensing the presence of a tiny magnet using a Hall effect sensor. There are certainly some advantages to this approach, but in practice, [OrangeTungsten] says the retrofitted magnet would keep falling off and leaving the projector inoperative. The fix was simple enough: figure out how the circuit worked, pull out the Hall effect sensor, and replace it with a simple button that would physically make contact with the door frame.
It’s not a terribly complex fix, but it’s a clever solution and well documented, and that goes pretty far around these parts. We were also interested in this one because an examination of the electronics inside the projector uncovered a 8-pin microcontroller — the sole purpose of which would appear to be polling the Hall effect sensor and using its status to throw a transistor which in turn powers the LED.
It’s hard to believe that whoever designed this gadget couldn’t figure out how to turn an LED on and off without a MCU, but we’re living in strange times. We assume there’s some kind of justification for this, such as some flashing or fading effects, but [OrangeTungsten] never mentions the things doing anything more complex than simply turning on and off.
Whatever the rationale was behind the original design of these projectors, the important thing is that the application of some hardware from the parts bin got them up and working again, which is something we never get tired of seeing.
I’ve always found those logo projectors to be rather tacky (whether they be on a car or a gaming monitor).
That’s what I think of it, too. Had Cupra rental car a while back and thought the projected logo was stupid – a waste of energy and resources.
If I had to do anything at all to one of those projectors, I’d just disable and be done with it.
Logo projectors, yes. But the first of those projectors lit the floor around the door area, so you could see whether you put your foot in a puddle (or dogxrement). Very functional.
Later some brands added their logo, and now it has updated to only logo and no light around it.
It’s always good work figuring out a fix to an issue.
But agreed, I can’t say I’ve ever really understood the appeal, at least in the case of projecting the make or model of something.
For me personally, I know what car I drive, or monitor I use and don’t really feel the need to advertise it.
But then, different strokes and all that I suppose.
ESP32-S3 is better than ESP32 for blinking an LED.
Mechanical switch has no code in it therefore no IP to protect with your team of white shoe lawyers…
And a hall sensor has no moving parts and doesn’t need to be exposed to the elements.
I would replace the lens that creates the logo for a bright LED to light up the pavement so you can see clearly where to step while entering or exiting the car at night. Often puddles, curb, or potholes can be near the door and be avoided if properly lit.
This.
(or at least I’d put a batman logo)
Automotive guy here.
Not sure where the contact or magnet point needs to be, but in automotive and this area you need to take care of dirt, water and human feet. Beside this you want to keep the cost low. So the Hall sensor + magnet might be the more cost efficient solution to a ruggedized and IPxx end switch.
I don’t get why the magnet is “retrofitted and keeps falling off”, can’t it be just fixed by improving the magnets fixation?
From the images in the git, I get the impression, this projector is a cheap aftermarket part installed by the car owner itself (mounted/glued? just on the lower inside of the door) and the magnet was probably just mounted by default with a glue-tape on the door frame itself.
This has to fail rather fast in this position.
It gets worse, the projector runs on 3xAA batteries!
They didn’t even use any sort of robust automotive switch, just a cheap unsealed tactile button attached with HOT GLUE with loose wires routed around the door frame. To claim that the non-contact sensor is “shady” in comparison just boggles the mind.
Just attach the magnet properly!
Does it come with an ad blocker?
Nice!
IMHO, classic example of useful feature that went south and had never returned.
I’d throw away entire thing and spilce into the dome light wire, meaning, put LEDs into each door, and all four would light up once the dome light is on. Do you REALLY need each individual door to have its own dedicated/independent LED with its own dedicate circuitry? I see no reasons why, and I’d also sell the four remaining circuits with their logos on ebay recovering the cost of proper downgrade.
Modern cars already come missing critical/important features that are actually needed, door light was one of them. Oh, there used to be ANOTHER light in the luxury cars’ doors of the past – it was usually facing backwards, ie, it was a safety light warning other drivers near that the door is open. Modern cars are shiny beacons of lights overall, so those lights are no longer relevant, but there are other places where one would need lights on, for example, proper lights marking the perimeter of the car. Those are not needed for the cars painted some kind of light colors, but all those ugly duckling non-glossy black kinds, that seem to be popular in my area, don’t reflect much, I am guessing we have some kind of overabundance of James Bonds villains in my particular area, and I am kind of glad they usually announce their arrival/departure with the loud cherry bomb lack of proper muffler instead.
Regardless, we are very, very long overdue for returning good solid thinking cars-wise. I’ll bring another topic that’s actually dark important – how do you gauge the breaking of the car in front of you? By visual feedback how fast you are approaching you? That’s stone-age gauging, we are still stuck with this stupid “light-on/light-off” binary indication, whereas a simple three-bar (or three dots, or thee squares, WHATEVER) would do far better, one bar – light tapping, two bars – slowing down, three bars – hard stop. Simple and more efficient than the binary on/off and darn a lot of guessing. Simple/cheap inertial sensor could take care of the measuring the deceleration and trigger the lights without external circuitry, and it is just a matter of baking inertial sensor into 8-bit MCU, and I wager it would cost about the same as the mentioned logo projector MCU with a hall sensor.
Actually, things of this nature had long been solved by the airplanes industry – car beacons could transmit the speed/bearing/etc to other cars around, and average car can automagically sense other cars around without needing LIDARs and AI. But who am I to point out the obvious, just a rangom rambler on HaD.
Pardon the autocarrot righting things I didn’t nintendo :]
Apparently the autocarrot is needed, too bad it cannot prevent you from “braking” grammar.
I once worked for a large US automaker and submitted a design for a deceleration-rate-based high mount stop light flasher, very much as you described, back around 1991. Wrote up a paper on it and everything. Never heard back from management or legal. At least I am not alone thinking it was a viable idea; thanks!
That, too, and my three-bar braking light could have been regulated to have certain minimum/maximum sizing, so the distance/acceleration can be guessed with a simple AI looking at these from the car following these.
I also like how very, very VERY suddenly car makers found out that they can add the line following, congrats, they are now, more than 60 years later, are FINALLY arriving at the 1960s level of DYI/amateur robotics : ]
Preston Tucker, we need you around with your Tucker Torpedo 2.0.
Congratulations, they’ve added in all of the pitfalls of a line follower.
I dove down a section of highway the other day where one highway splits into three. Each of the new three lanes has the number of the highway painted in the middle of the lane. Big, tall letters, about the size of a car. The digits were in white, just like the lane markers.
My idiot car with “lane assist” tried to “follow the lane” using the highway number as a lane indicator. Cue cursing and fighting as I force my car to stay in the lane I needed.
Had my wife reach over and turn off the lane assist after that. It unfortunately turns itself back on every time you start the car.
I’ve used it, too – on rental cars. Results were good when/if facing long uninterrupted lines, it would warn of one swerving slightly to the side, yes. Predictably, the line following is implemented at the level of a third grader, it couldn’t compile anything beyond uninterrupted solid lines. It kept getting confused with anything else.
That’s why my reply was SARCASM – they’ve just now discovered the line following robot functionality. Discovering the rest was above and beyond, so they stopped at naive/simple things they could figure out and sell at ten prices.
Have the car makers been paying attention to the reality, they’d be implementing things like low-cost solar-powered beacons atop of all major spots, highway signs, exit signs, red lights, where they are needed, but car manufacturers are not living in reality. They also pretend airplanes industry doesn’t exist, nor they care to know that some logistics were ALREADY figured out in the early 1980s, using analog electronics and common sense.
I own old school cars with no uber this and that for the simple reason that I do not see a need to waste my time paying car loan with expensive toys I’ve never asked for. I fully intend on driving them until they crack in half from rust, or I die of old age, whichever comes first. Old good ICE cars, not EV, and I don’t give a damn about what industry thinks about this. Once powertran goes out, I’ll just transplant a new one and keep going.
I guess I should be clear that a lot of times it is sarcasm that I am relying. Sarcasm is better than outright vitriol, I suppose.
so, the car knows when the door is open, it will give you a warning in the dashboard, so, why does it need an extra sensor for the projector? this seems like either overengineering, or waste of resources
Exactly lol, in my car there is no sensor, just the +/- for the puddle light
Because it´s an Aliexpress part, powered by batteries, and not connected electrically in any way to the car.
Hmm…logo projector seems like a frivolous doodad. But, fixing an over complicated activation method is a good hack.
Nobody noticed the “cheap AFTERMARKET car logo projectors” (stress on “aftermarket”) in the github page?
That would be an answer to most of the doubts expressed in the previous comments.
Are we sure it’s a microcontroller and not just an op-amp, comparator, or LVTTL buffer? All it needs to do is amplify the Hall sensor voltage into a gate drive signal.
Was wondering that myself, I bet it’s just a mosfet fed the output of the hall sensor and is used to switch the higher current of the LED.
Oh, and here I thought it was just an MCU that’s cheaper than a 555.
Why even switch the light off? It’s a low power led. Just place it on the bottom of the door where it’s not visible when the door is closed, and leave it on while the car is switched on.
It isn’t factory, or wired to the cars 12V system. Triple A battery all the way!
It is a cheap aftermarket item. The whole idea falls apart when we realize the battery attachment is due to the complete design fail of the design.
Wait until it’s cloud based and a server somewhere sends a message to turn on the light bulb if your subscription is being paid…
So this person has bought something to add more branding to their car… on purpose… and spent time counteracting the thing’s one redeeming feature, that it broke.