Current Sensor Makes Intriguing Use Of Concrete

October 8, 2020 by Bryan Cockfield 20 Comments

Getting a product to market isn’t all about making sure that the product does what it’s supposed to. Granted, most of us will spend most of our time focusing on the functionality of our projects and less on the form, fit, or finish of the final product, especially for one-off builds that won’t get replicated. For those builds that do eventually leave the prototyping phase, though, a lot more effort goes into the final design and “feel” of the product than we might otherwise think. For example, this current sensor improves its feel by making use of cast concrete in its case.

The current sensor in this build is not too much out of the ordinary. [kevarek] built the sensor around the MCA1101-50-3 chip and added some extra features to improve its electrostatic discharge resistance and also to improve its electromagnetic compatibility over and above the recommended datasheet specifications. The custom case is where this one small detail popped out at us that we haven’t really seen much of before, though. [kevarek] mixed up a small batch of concrete to pour into the case simply because it feels better to have a weightier final product.

While he doesn’t mention building this current sensor to sell to a wider audience, this is exactly something that a final marketable product might have within itself to improve the way the device feels. Heavier things are associated, perhaps subconsciously, with higher quality, and since PCBs and plastic casings don’t weigh much on their own many manufacturers will add dummy weights to improve the relationship between weight and quality. Even though this modification is entirely separate from the function of the product, it’s not uncommon for small changes in design to have a measurable impact on performance, even when the original product remains unmodified.

Thanks to [Saabman] for the tip!

The Prusa I3 MK3S And A Tale Of Two Sensors

October 8, 2020 by Tom Nardi 78 Comments

When the Prusa i3 MK3 was released in 2017, it was marketed as being “bloody smart” thanks to the impressive number of sensors that had been packed into the printer. The update wasn’t really about improving print quality over the MK2, but rather to make the machine easier to use and more reliable. There was a system for resuming prints that had stopped during a power outage, a thermometer so the firmware could compensate against thermal drift in the inductive bed sensor, RPM detection on all of the cooling fans, and advanced Trinamic stepper drivers that could detect when the printer had slipped or gotten stuck.

The optical filament sensor of the Prusa i3 MK3.

But the most exciting upgrade of all was the new filament sensor. Using an optical encoder similar to what you’d find in a mouse, the Prusa i3 MK3 could detect when filament had been inserted into the extruder. This allowed the firmware to pause the print if the filament had run out, a feature that before this point was largely unheard of on consumer-grade desktop 3D printers. More than that, the optical encoder could also detect whether or not the filament was actually moving through the extruder.

In theory, this meant the MK3 could sense problems such as a jammed extruder or a tangle in the filament path that was keeping the spool from unrolling. Any other consumer 3D printer on the market would simply continue merrily along, not realizing that it wasn’t actually extruding any plastic. But the MK3 would be able to see that the filament had stalled and alert the user. The capabilities of the optical filament sensor represented a minor revolution in desktop 3D printing, and combined with the rest of the instrumentation in the MK3, promised to all but eradicate the heartbreak of failed prints.

Fast forward to February of 2019, and the announcement of the Prusa i3 MK3S. This relatively minor refresh of the printer collected up all the incremental tweaks that had been made during the production of the MK3, and didn’t really add any new features. Though it did delete one: the MK3S removed the optical encoder sensor used in the MK3, and with it the ability to sense filament movement. Users would have to decide if keeping the ability to detect clogs and tangles was worth giving up all of the other improvements offered by the update.

But why? What happened in those three years that made Prusa Research decide to abandon what promised to be a huge usability improvement for their flagship product? The answer is an interesting look at how even the cleverest of engineering solutions don’t always work as expected in the real-world.

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NVIDIA Announces $59 Jetson Nano 2GB, A Single Board Computer With Makers In Mind

October 5, 2020 by Tom Nardi 47 Comments

NVIDIA kicked off their line of GPU-accelerated single board computers back in 2014 with the Jetson TK1, a $200 USD development system for those looking to get involved with the burgeoning world of so-called “edge computing”. It was designed to put high performance computing in a small and energy efficient enough package that it could be integrated directly into products, rather than connecting to a data center half-way across the world.

The TK1 was an impressive piece of hardware, but not something the hacker and maker community was necessarily interested in. For one thing, it was fairly expensive. But perhaps more importantly, it was clearly geared more towards industry types than consumers. We did see the occasional project using the TK1 and the subsequent TX1 and TX2 boards, but they were few and far between.

Then came the Jetson Nano. Its 128 core Maxwell CPU still packed plenty of power and was fully compatible with NVIDIA’s CUDA architecture, but its smaller size and $99 price tag made it far more attractive for hobbyists. According to the company’s own figures, the number of active Jetson developers has more than tripled since the Nano’s introduction in March of 2019. With the platform accessible to a larger and more diverse group of users, new and innovative applications for machine learning started pouring in.

Cutting the price of the entry level Jetson hardware in half was clearly a step in the right direction, but NVIDIA wanted to bring even more developers into the fray. So why not see if lightning can strike twice? Today they’ve officially announced that the new Jetson Nano 2GB will go on sale later this month for just $59. Let’s take a close look at this new iteration of the Nano to see what’s changed (and what hasn’t) from last year’s model.

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Choosing The Right RTC For Your Project

September 30, 2020 by Lewin Day 27 Comments

When it comes to measuring time on microcontrollers, there’s plenty of ways to go about things. For most quick and dirty purposes, such as debounce delays or other wait states, merely counting away a few cycles of the main clock will serve the purpose. Accurate to the tens of milliseconds, they get the average utility jobs done without too much fuss.

However, many projects are far more exacting in their requirements. When you’re building a clock, or a datalogger, or anything that relies on a stable sense of passing time for more than a few minutes, you’ll want a Real Time Clock. So called due to their nature of dealing with real time, as we humans tend to conceive it, these devices take it upon themselves to provide timekeeping services with a high degree of accuracy. We’ve compiled a guide to common parts and their potential applications so you can get things right the first time, every time.

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WiFi Hacking Mr. Coffee

September 29, 2020 by Adam Zeloof 42 Comments

You wake up on a Sunday, roll out of bed, and make your way to the centerpiece of your morning, the magical device that helps you start your day: the coffee machine. You open the companion app, because everything has an app in 2020, and select a large latte with extra froth. As you switch open a browser to check Hackaday, the machine beeps. Then the built-in grinder cranks up to 100, the milk frother begins to whir, and the machine starts spraying water. Frantic, you look at the display for an error code and instead see a message instructing you to send $75 to a bitcoin wallet, lest your $300 machine become a doorstop.

Outlandish though it may seem, this has become quite a real possibility, as [Martin Hron] at the Avast Threat Labs demonstrates. In fact, he could probably make your modern macchiato machine do this without setting foot in your house (so long as it comes with a built-in ESP8266, like his did).

Building on others’ work that identified the simple commands that control the machine over it’s WiFi connection (nothing says “brew me a nice cup o’ joe” like 0x37), [Martin] reverse-engineered the Smarter Coffee companion app to extract and reverse engineer its firmware. He was actually able to find the entire firmware image packaged within the app- relatively uncommon in the world of Over-The-Air (OTA) updates, but convenient in this case. Using Interactive Disassembler (IDA) to sift through the firmware’s inner workings, he identified the functions that handle all basic operations, including displaying images on the screen, controlling the heating elements, and of course, beeping. From there, he modified the stock firmware image to include some malicious commands and ran an OTA update.

The mind-boggling part here is that not only was the firmware transmitted as unencrypted plaintext over unsecured WiFi, but the machine didn’t even require a user to confirm the update with a button press. With one quick reboot, the trap was set. The machine operated normally, while waiting for “Order 66,” causing it to turn all the heating elements on, spool up the built-in grinder, and beep. Constantly.

While a broken coffee machine seems relatively innocuous, there are some pretty significant lapses in hardware/firmware security here that, while avoidable, almost seem unnecessary in the first place. It makes us wonder- why does Mr. Coffee need a smartphone in the first place?

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Check Your Pockets For Components

September 28, 2020 by Brian McEvoy 13 Comments

The ideal component tester is like a tricorder for electronics — it can measure whatever it is that you need it to, all the time. Maybe you have a few devices like an ohmmeter and maybe a transistor socket on our multimeter. But what do you do when you need to see if that thyristor is faulty? [Akshay Baweja] wants an everything-tester at the ready, so he’s building a comprehensive device that fits in a pocket. It will identify the type and size of: Continue reading “Check Your Pockets For Components” →

A Battery To Add A Tingling Sensation To Your Tweets

September 27, 2020 by Sven Gregori 28 Comments

Internet-connected sex toys are a great way to surprise your partner from work (even the home office) or for spicing up long-distance relationships. For some extra excitement, they also add that thrill of potentially having all your very sensitive private data exposed to the public — but hey, it’s not our place to kink-shame. However, their vulnerability issues are indeed common enough to make them regular guests in security conferences, so what better way to fight fire with fire than simply inviting the whole of Twitter in on your ride? Well, [Space Buck] built just the right device for that: the Double-Oh Battery, an open source LiPo-cell-powered ESP32 board in AA battery form factor as drop-in replacement to control a device’s supply voltage via WiFi.

Battery and PCB visualization — Double-Oh Battery with all the components involved

In their simplest and cheapest form, vibrating toys are nothing more than a battery-powered motor with an on-off switch, and even the more sophisticated ones with different intensity levels and patterns are usually limited to the same ten or so varieties that may eventually leave something to be desired. To improve on that without actually taking the devices apart, [Space Buck] initially built the Slot-in Manipulator of Output Levels, a tiny board that squeezed directly onto the battery to have a pre-programmed pattern enabling and disabling the supply voltage — or have it turned into an alarm clock. But understandably, re-programming patterns can get annoying in the long run, so adding WiFi and a web server seemed the logical next step. Of course, more functionality requires more space, so to keep the AA battery form factor, the Double-Oh Battery’s PCB piggybacks now on a smaller 10440 LiPo cell.

But then, where’s the point of having a WiFi-enabled vibrator with a web server — that also happens to serve a guestbook — if you don’t open it up to the internet? So in some daring experiments, [Space Buck] showcased the project’s potential by hooking it up to his Twitter account and have the announcement tweet’s likes and retweets take over the control, adding a welcoming element of surprise, no doubt. Taking this further towards Instagram for example might be a nice vanity reward-system improvement as well, or otherwise make a great gift to send a message to all those attention-seeking people in your circle.

All fun aside, it’s an interesting project to remote control a device’s power supply, even though its application area might be rather limited due to the whole battery nature, but the usual Sonoff switches may seem a bit unfitting here. If this sparked your interest in lithium-based batteries, check out [Lewin Day]’s beginner guide and [Bob Baddeley]’s deeper dive into their chemistry.