[Ross] has a 2008 Toyota Tacoma. Like many late model cars, each tire contains a direct tire pressure monitoring sensor or TPMS that wirelessly sends data about the tire status to the car. However, unlike some cars, the system has exactly one notification to the driver: one of your tires is low. It doesn’t tell you which one. Sure, you can check each tire, but [Ross] had a different problem. One sensor was bad and he had no way to know which one it was. He didn’t have any equipment to test the sensor, but he did have an RTL-SDR dongle and some know-how to figure out how to listen in on the sensors.
The key was to use some software called RTL-433 that is made to pick up these kinds of signals. It is available for Linux, Windows, or Mac, and supports hundreds of wireless sensors ranging from X10 RF to KlikAanKlikUit wireless switches.
It’s fascinating to see what happens when a creative hacker is given a set of constraints to work within. [rctestflight] found themselves in a very specific set of circumstances: Free RC cars from sponsors, and no real purpose for them. Instead of just taking them apart to see what made them tick (itself the past time of many a beginning hacker), [rctestflight] decided to let the RC cars disassemble themselves, destructively, on their way to 100,000 (scale) RC Car Miles, tallying up the distance (and the carnage) in the end as you see in the video below the break.
Can you spot the RC car under the mud?
Re-using a jig and test track (his backyard) from another test, [rctestflight] set up solar powered tether that could power any of the vehicles under test. The vehicles were modified as needed to drive along the circular track on a tether, and once stability was achieved, the cars were set on their own to either drive 100,000 scale miles or die trying.
Seeing as how [rctestflight] hales from the Pacific NorthWet of the United States near Seattle, the endurance test turned out to be not just a test of distance. Among the factors evaluated were how well each vehicle could withstand the mud, grime, and yes, even earthworms, that awaited them.
After each vehicle failed beyond the point of a quick fix, they were all torn down. Where each manufacturer cut corners could clearly be seen, and the weaknesses and strengths of each vehicle were pretty interesting. Plus, there’s a pretty great (awful) uh… rendition… of an iconic 80’s song. Twice. And of course the final conclusion: Exactly how many miles did each vehicle go before catastrophic failure? Check the video for results.
Regular readers will know that [rctestflight] is somewhat of a Hackaday regular, with plentiful great hacks such as this drone boat that sails the high seas of Lake Washington.
When you want to fabricate something you either start with something and take away what you don’t want — subtractive manufacturing — or you start with nothing and add material, which is additive manufacturing that we usually call 3D printing. Popular Science recently took a look inside Vital Auto, the British lab that uses 3D printing for high-end concept cars from companies like Rolls-Royce, McLauren, Jaguar, and others. In the video below, [Anthony Barnicott], an engineer for Vital, says that the two technologies — additive and subtractive — work best when used together.
As you might expect, they are not using a $200 FDM printer. They have three Formlabs 3Ls that print with resin and five Formlab Fuse 1 selective laser sintering printers. While metal printers are still uncommon in hacker’s workshops, resin printers are now very affordable although your garage printer is probably a good bit smaller than the 3L’s 335x200x300 mm volume. For comparison, an LCD-based AnyCubic Photon X provides just 165x132x80 mm. Of course, you’re looking at about $11,000 for the dual-laser 3L versus about $240 for the Photon.
Vital started building the EP9 electric car concept for NIO, an electric car maker in China. You can imagine that modern manufacturing machines make it possible to create more sophisticated concept cars faster. How many times do you want to tweak a part that takes a machinist eight hours to produce? But if you can just let a machine run overnight and get the result in the morning, you are more likely to change and refine the part.
Vital Auto is an interesting look at how professional fabrication shops are using the same technologies we do, at least at the core. We’ve noted before how these same technologies are making homebrew projects look better than some commercial products not long ago. You can print big things if you break them up, of course. Or, break the bank and buy a really big printer.
Last month Kia Motors announced a large recall due to possibly defective airbag controller units (ACU). The recall spans many models and model years — in the United States alone it covers over 400K cars, and over half a million cars worldwide. From the NHTSA report we learn that the problem happened at assembly when the cover of some ACUs interfered with the pins of an EEPROM chip. This can cause some of the pins to open-circuit. If your car had this problem, a warning light would come on, but more seriously, the airbags would not deploy in an accident. Kia estimates that less than 1% of the cars using this ACU have this issue. Cars which have this fault will get a new ACU, and other cars will get a firmware upgrade to keep this from happening should the EEPROM pins break loose in the future.
We think this EEPROM is used for logging errors and crash events, and is therefore not in the critical path for airbag deployment. The original firmware apparently prevented deployment if the EEPROM had a fault. Presumably, after this patch, if pins break in the future, the fault indicator still lights up but you’ll have functioning airbags.
It’s not clear if these broken EEPROM pin solder joints were present from the start and the factory test procedures didn’t catch the problem. Or did the pins left the factory intact and were subsequently broke due to bumps and vibrations. Hardware issues aside, having safety critical firmware perform its primary function even when faults exist in non-essential parts of the circuit seems like a requirement that should have been applied to the ACU from the beginning.
This is a reminder of the importance of enclosure design and making sure your PCB layouts take into account all clearances necessary for the entire assembly. How many times have you got your PCB back and realized you forgot to even put mounting holes?
At its core, the concept of vehicle-grid integration (VGI) – also called Vehicle To Grid (V2G) – seems a simple one. Instead of a unidirectional charger for battery-electric vehicles (BEVs), a bidirectional charger would be used. This way, whenever the BEV is connected to such a charger, power could be withdrawn from the car’s battery for use on the local electrical grid whenever there’s demand.
Many of the complications with VGI have already been discussed, including the increased wear that this puts on a BEV’s battery, the need for an inherently mobile machine to be plugged into a charger, and the risk of needing one’s BEV and finding its battery to be nearly depleted. Here the cheerful marketing from Nissan and that from commercial initiatives such as Vehicle to Grid Britain makes it sound like it’s a no-brainer once those pesky details can be worked out.
In parallel with the world of glossy marketing leaflets, researchers have been investigating VGI as a potential option for grid-level energy storage. These studies produce a far less optimistic picture that puts the entire concept of VGI into question.
When you think of “car rim” you probably think stamped steel or machined alloy with a sturdy drum to withstand the arduous life of the road, not something 3D printed out of ABS. That would be crazy, right? Not to [Jón Schone] from Proper Printing, who’s recently released an update about his long-term quest to outfit his older sedan with extruded rims.
There were a few initial attempts that didn’t go as well as hoped. The main issue was layer separation as the air pressure would stretch the piece out, forming bubbles. He increased the thickness to the absolute maximum he could. A quick 3D scan of the brake caliper gave him a precise model to make sure he didn’t go too far. He also couldn’t make the rim any bigger to fit a bigger wheel to clear the caliper, as he was already maxing out his impressive 420 mm build volume from his modified Creality printer.
A helpful commenter had suggested using a threaded rod going all the way through the print as a sort of rebar. After initially discounting the idea as the thickness of the rim gets really thin to accommodate the caliper, [Jón] realized that he could bend the rods and attach the two halves that way. Armed with a paper diagram, he cut and bent the rods, inserting them into the new prints. It’s an impressive amount of filament, 2.7 kg of ABS just for one-half of the rim.
It didn’t explode while they inflated the tire and it didn’t explode while they did their best to abuse it in the small alley they had selected for testing. The car was technically no longer road legal, so we appreciate their caution in testing in other locations. In a triumphant but anti-climatic ending, the rim held up to all the abuse they threw at it.
We’ve been following this project for several months now, and are happy to see [Jón] finally bring this one across the finish line. It sounds like there’s still some testing to be done, but on the whole, we’d call the experiment a resounding success.
Small is often subjective. For example, a school bus is small compared to an Airbus A380. But other things are just small all on their own and need no comparison to make the point. Such is the case with this micro RC car in the video below the break. It’s an RC model of the Smart Car, that when compared to other vehicles on the road, is quite diminutive, both subjectively and absolutely. But the outward appearance of [diorama111]’s project only tells half the story.
Starting out as a static display model, [diorama111] fully disassembled the 1/87 scale Smart Car and got to work. Fully proportional steering is attained with a very, very small stepper motor that drives custom knuckles attached to handmade suspension. They are works of art in their own right.
Do your projects need tweezers for assembly?
Drive is supplied by another small stepper motor. If [diorama111] had stopped there, it would have been every bit as noteworthy to see a 1/87 Smart Car doing figure eights around small bottles of model paint. Instead, [diorama111] kept going! The car has working turn signals, brake lights (including the 3rd taillight in the back window!) and headlights. There is even a function for hazard lights.
The electronics are all hand built using enameled wire and SMD components on perf board, and are a study in miniaturization all their own. An ATtiny processor seems right at home in this design. We admire [diorama111]s steady hands and patience to build such a small RC car, never mind one with such fine attention paid to all the details.
