Ski Season Sees Apple’s Crash Detection System Fire Deluge Of False Positives

February 9, 2023 by Lewin Day 39 Comments

Smartphone features used to come thick and fast. Cameras proliferated, navigation got added, and then Apple changed the game by finally making touch computing just work. Since then, truly new features have slowed to a trickle, but Apple’s innovative crash detection system has been a big deal where safety is concerned.

The problem? It’s got a penchant for throwing false positives when iPhone and Apple Watch users are in no real danger at all. We first covered this problem last year, but since then, the wintery season has brought yet more issues for already-strained emergency responders.

Continue reading “Ski Season Sees Apple’s Crash Detection System Fire Deluge Of False Positives” →

LED Driver Circuit For Safety Hat Sucks Single AAA Cell Dry

January 19, 2023 by Donald Papp 21 Comments

[Petteri Aimonen] created an omnidirectional LED safety light to cling to his child’s winter hat in an effort to increase visibility during the dark winter months, but the design is also great example of how to use the Microchip MCP1640 — a regulated DC-DC step-up power supply that can run the LEDs off a single AAA cell. The chip also provides a few neat tricks, like single-button on/off functionality that fully disconnects the load, consuming only 1 µA in standby.

[Petteri]’s design delivers 3 mA to each of eight surface-mount LEDs (which he says is actually a bit too bright) for a total of about 20 hours from one alkaline AAA cell. The single-layer PCB is encased in a clear acrylic and polycarbonate enclosure to resist moisture. A transistor and a few passives allow a SPST switch to act as an on/off switch: a short press turns the unit on, and a long press of about a second turns it back off.

One side effect is that the “off” functionality will no longer work once the AAA cell drained too badly, but [Petteri] optimistically points out that this could be considered a feature: when the unit can no longer be turned off, it’s time to replace the battery!

The usual way to suck a battery dry is to use a Joule Thief, and while this design also lights LEDs, it offers more features and could be adapted for other uses easily. Interested? [Petteri] offers the schematic, KiCAD file for the PCB, and SVG drawing of the enclosure for download near the bottom of the project page.

Bicycle Gets Turn Signals And Brake Lights For Added Safety

November 28, 2022 by Bryan Cockfield 27 Comments

Traveling by bicycle can be a fun and exciting mode of transportation, and can also save a ton of money compared to driving a car. There are plenty of places around the world where a bicycle is the primary mode of transportation for a significant percentage of the population, but there are many more places that are designed entirely for cars with little thought given to anyone else. For anyone riding a bike, especially for people living in these car-dominated areas, additional safety measures like this LED array are often necessary.

The light array was created by [Estudio Roble] for traveling around his city. The design is based on the Adafruit Circuit Playground Express, which sits directly in the middle of the light fixture. Surrounding it is a diamond-shaped strip of LEDs within an additional ring. The light uses a bright blue color for normal driving, but is programmed to turn red when the accelerometer in the dev board detects braking. There are also integrated turn signals which operate similarly to motorcycle turn signals. The signal is sent wirelessly between the handlebar switch to the lights.

The device itself clips onto any backpack, and since the controller is wireless there are no wires to connect every time a rider gets on their bike. It’s quite an improvement over the complete lack of lighting on most bikes. If you’ve read this far, you need to check out this bicycle headlight which uses a projector to display information directly in the path of travel.

Continue reading “Bicycle Gets Turn Signals And Brake Lights For Added Safety” →

Recreating The “Stuck Throttle” Problem On A Toyota

October 30, 2022 by Bryan Cockfield 68 Comments

A few years ago, Toyota was in the news for a major safety issue with a number of their passenger vehicles. Seemingly at random, certain cars were accelerating without concern for driver input, causing many crashes and at least 37 confirmed deaths. They issued recalls both for the floor mats which were reported to have slid forward to jam the accelerator pedal, but this didn’t explain all of these crashes. There was another recall for stuck throttles, which [Colin O’Flynn] demonstrates a possible cause for on his test bench.

While most passenger vehicles older than about 15-20 years controlled the throttle with a cable connected directly from the throttle body to the accelerator pedal, most manufacturers have switched to a fly-by-wire system which takes sensor input from the accelerator pedal and sends that position information to the vehicle’s computer which in turn adjusts the throttle position. This might be slightly cheaper to manufacture, but introduces a much larger number of failure modes to a critical system. Continue reading “Recreating The “Stuck Throttle” Problem On A Toyota” →

USB Power Isolator Keeps Smoke In

October 12, 2022 by Bryan Cockfield 17 Comments

Anyone who’s done an electronics project knows the most important part of any good design is making sure to keep the magic smoke inside of all of the components. There are a lot of ways to make sure the smoke stays in there, but one of the most important is making sure that the power supply is isolated. If you’re using a USB port on a computer as your power source, though, it can be a little more complicated to isolate it from the computer.

The power supply is based around a small transformer with a set of diodes to act as a rectifier. Of course, while a transformer is great at isolating power supplies, it isn’t much good at DC. That’s what the ATtiny microcontroller is for. It handles the high-speed switching of the MOSFETs, which drive the transformer and handle some power regulation. There are two different power supplies created as part of this project as well — the first generates +5V much like a normal USB plug would have, and the other creates both +5V and -5V. It will be important not to mix these two up, or that tricky blue smoke may escape.

The project page goes into extensive details on the operation of the device, so if electrical theory is of interest, this will definitely be worth a read. Isolating a valuable computer from a prototype circuit is certainly important, but if you’re looking for a way to isolate a complete USB connection, look at this build which includes isolation for a USB to FTDI adapter.

The CPSC Says Plug To Socket, Not Plug To Plug, Please

September 17, 2022 by Jenny List 102 Comments

When the power goes out, it goes without saying that all the lights and sockets in a house stop working. Savvy rural homeowners stock up with candles, batteries, LED lights, and inverters. More foolhardy folks simply hook up their home electrical system to a generator using a mains lead with a plug on one end between the generator and a wall socket. This should be so obviously dangerous as to be unnecessary, but it’s become widespread enough that the US Consumer Product Safety Commission has issued a warning about the practice. In particular, they’re concerned that there’s not even a need to wire up a lead, as they’re readily available on Amazon.

The dangers they cite include electrocution, fire hazard from circumventing the house electrical protection measures, and even carbon monoxide poisoning because the leads are so short that the generator has to be next to the socket. Hackaday readers won’t need telling about these hazards, even if in a very few and very special cases we’ve seen people from our community doing it. Perhaps there’s a flaw in the way we wire our homes, and we should provide a means to decouple our low-power circuits when there’s a power cut.

It’s likely that over the coming decades the growth of in-home battery storage units following the likes of the Tesla Powerwall will make our homes more resilient to power cuts, and anyone tempted to use a plug-to-plug lead will instead not notice as their house switches to stored or solar power. Meanwhile, some of us have our own ways of dealing with power outages.

Plug image: Evan-Amos, Public domain.

Who Is Responsible For Your Safety?

September 10, 2022 by Elliot Williams 182 Comments

We recently posted a video where some ingenious metal-shop hackers made a simple jig to create zig-zag oil grooves on the inside of a cylinder, and the comment section went wild. What ensued was a flood of complaints that the video displayed unsafe shop practices, from lack of safety glasses to wearing flip-flops while operating a lathe.

Where the comments went off the rails were people asking Hackaday to remove our discussion of the video, because the commenters thought that we were somehow implicitly encouraging open-toed footwear in the presence of machine tools. We certainly weren’t! We wanted you all to see the clever machining hack, and be inspired to build your own. We figure that you’ve got the safety angle covered.

Now don’t get me wrong – there were safety choices made in the video that I would not personally make. But it also wasn’t my shop and I wasn’t operating the machines. And you know who is ultimately responsible for the safety in my basement shop? Me! And guess who is responsible for safety in your shop.

But of course, none of us know everything about every possible hazard. (Heck, I wrote just that a few weeks ago!) So while we’re sympathetic with the “that’s not safe!” crew, we’re not going to censor inspiring hacks just because something done along the way wasn’t done in the way we would do it. Instead, it’s our job, in the comment section as in Real Life™, to help each other out and share our good safety tips when we can.

You’ll see some crazy stuff in videos, and none of it is to be repeated without thinking. And if you do see something dodgy, by all means point it out, and mention how you would do it better. Turn the negative example around for good, rather than calling for its removal. Use the opportunity to help, rather than hide.

But also remember that when the chips are flying toward your personal eyeballs, it’s up to you to have glasses on. We all do potentially hazardous things all the time, and it’s best to be thinking about the risks and their mitigation. So stay safe out there. Keep on learning and keep on hacking!