Making An Arduino Ventilator? Read This First

April 5, 2020 by 70 Comments

Thanks to the virus crisis, lots of people are designing makeshift ventilator designs in the hopes of saving people’s lives. Many of these are based around some sort of Arduino-powered CPU. [Armstrong Subero] things that’s a great idea, but cautions that making an electronic pair of dice is a different proposition than creating a machine to breathe for someone. But he isn’t just complaining. He talks about considerations when building a real-time and safety-critical system.

[Armstrong] has a lot of good points, although we aren’t sure you need the complexity of a real-time operating system just to squeeze a bag. If anything, that seems like it might make it more susceptible to unexpected operation. However, we agree with his comments that you should have closed-loop control to make sure the device is working, alarming when the device isn’t working, and watchdog timers to guard against lockup.

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Data Glove Gets A Grip On Gesture Input

April 5, 2020 by 3 Comments

If we really want wearable computing to take off as a concept, we’re going to need lightweight input devices that can do some heavy lifting. Sure, split ergo keyboards are awesome. But it seems silly to restrict the possibilities of cyberdecks by limiting the horizons to imitations of desk-bound computing concepts.

What we really need are things like [Zack Freedman]’s somatic data glove. This fantastically futuristic finger reader is inspired by DnD spells that have a somatic component to them — a precise hand gesture that must be executed perfectly while the spell is spoken, lest it be miscast. The idea is to convert hand gestures to keyboard presses and mouse clicks using a Teensy that’s housed in the wrist-mounted box. You are of course not limited to computing on the go, but who could resist walking around the danger zone with this on their wrist?

Each finger segment contains a magnet, and there’s a Hall effect sensor in each base knuckle to detect when gesture movement has displaced a magnet. There’s a 9-DoF IMU mounted in the thumb that will eventually allow letters to be typed by drawing them in the air. All of the finger and thumb components are housed in 3D-printed enclosures that are mounted on a cool-looking half glove designed for weightlifters. [Zack] is still working on gesture training, but has full instructions for building the glove up on Instructables.

It’s true: we do love split ergo keyboarded cyberdecks, and this one is out of this world.

The CLUE Tracker Points You To A Target, Using CircuitPython

April 5, 2020 by 2 Comments
The main components are an Adafruit CLUE, Stemma GPS, and a lithium-polymer battery. No soldering required.

[Jay Doscher] shares a quick GPS project he designed and completed over a weekend. The device is called the CLUE Tracker and has simple goals: it shows a user their current location, but also provides a compass heading and distance to a target point. The idea is a little like geocaching, in that a user is pointed to a destination but must find their own way there. There’s a 3D printed enclosure, and as a bonus, there is no soldering required.

The CLUE Tracker uses the Adafruit CLUE board (which is the same size as the BBC micro:bit) and Stemma GPS sensor, with the only other active component being a lithium polymer battery. The software side of the CLUE Tracker uses CircuitPython, and [Jay] has the code and enclosure design available on GitHub.

[Jay] did a nice job of commenting and documenting the code, so this could make a great introductory CircuitPython project. No soldering is required, which makes it a little easier to re-use the parts in other projects later. This helps to offset costs for hackers on a budget.

The fact that a device like this can be an afternoon or weekend project is a testament to the fact that times have never been better for hobbyists when it comes to hardware. CircuitPython is also a fast-growing tool, and projects like this can help make it easy and fun to get started.

Turn Off Those Batteries With Their Protection Chip

April 5, 2020 by 24 Comments

It should be a feature of every device powered by a lithium-ion battery, that it has a protection chip on board that automatically disconnects it should it go out of its safe voltage range. A chip most often used for this purpose in single-cell applications is the Fortune Semiconductor DW01, and [Oliver] shares a tip for using this chip to power down the battery. The DW01 has a CS, or current sense pin, which if taken high momentarily will put the chip into an off state until the battery is disconnected.

Looking at the DW01 datasheet we can see that this would work, but we can’t help having a few questions. The CS pin is a safety sensor pin, providing over current, short circuit, and reverse polarity detection. It’s the kind of pin one might mess with only when one is absolutely certain it’s not likely to trigger a dangerous fault condition, so a bit of care should be required. However, we can see that leaving its resistor in place and supplying it a momentary logic level through another resistor should work. We’d be interested in the views of any readers with more experience in the world of lithium battery protection on this hack.

Meanwhile, a good read for any reader should be our look last year at lithium-ion safety.

R/C Toilet Paper Roll Is The Hero We Deserve

April 4, 2020 by 11 Comments

For reasons that most rational consumers can’t fathom, a not inconsiderable segment of the population believes the key to their continued survival during a pandemic unprecedented in modern times is to stockpile toilet paper. This leaves those of us not compelled to act based on the whims of our bowels looking at bare racks in the paper product aisle more often than not.

Which makes it the perfect time for [Ariel Yahni] to develop his remote controlled toilet paper roll. With this gadget deployed, you just might have a chance at drawing the Karens away from all the rolled gold long enough to grab yourself a pack. Even if it doesn’t distract the other competitors shoppers, you can at least enjoy the looks on their faces as it scurries by.

The project starts with, of all things, popsicle sticks. These are used to make a reinforced platform to which the two motors, radio receiver, speed controller, and battery are mounted. With some clever packing, [Ariel] is able to (tightly) fit it inside of a cardboard tube with just the bottoms of the two wheels protruding through cutouts. A careful wrapping with toilet paper is then used to give it the look of a partially used roll, including a trailing “tail” that flutters in its wake.

In the video after the break, you can see [Ariel] take his roll of motorized TP through a local mall for a test drive. We’re sorry to say that nobody appears to make a wild dive for it during the test. But that could be because the video was recorded back in December before people had resorted to fighting over toiletries. It also explains why he was able to get into a mall in the first place.

Just think, if we had embraced the high-tech toilets of the future back when we had a chance, we could have avoided this whole thing. As far as dystopias go, this one is shaping up to be pretty weird.

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An Adapter To Solve Your ESP-01 Breadboard Woes

April 4, 2020 by 9 Comments

The ESP-01 launched the ESP8266 revolution back in 2014, and while today you’re far more likely to see somebody use a later version of the chip in a Wemos or NodeMCU development board, there are still tasks the original chip is well suited for. Unfortunately, they can be tricky to use while prototyping because they aren’t very breadboard friendly, but this adapter developed by [Miguel Reis] can help.

Of course, the main issue is the somewhat unusual pinout of the ESP-01. Since it was designed as a daughter board to plug into another device, the header is too tight to fit into a breadboard. The adapter that [Miguel] has come up with widens that up to the point you can put it down the centerline of your breadboard and have plenty of real estate around it.

The second issue is that the ESP-01 is a 3.3 V device, which can be annoying if everything else in the circuit is running on 5 V. To get around this, the adapter includes an SPX3819 regulator and enough capacitors that the somewhat temperamental chip gets the steady low-voltage supply it needs to be happy.

[Miguel] has released the schematics and board files so you can spin up your own copy of the adapter, but they’re also available for around $3 USD from his Tindie store.

Typing By Slamming Your Laptop Closed. Repeatedly

April 4, 2020 by 26 Comments

Do you sometimes feel that your custom mechanical keyboard is not quite loud enough to proclaim your superior hacking powers? Or do you need a more forceful way shout in all caps at someone who is wrong on the internet? For all this and more, [Jesse Li] has got you covered, with a set of bash scripts that allows you to type by slamming your laptop closed repeatedly, using Morse code.

Not the fastest way to type, but definitely the most forceful

The scripts are quite simple, and work receiving the lid open/close events from ACPI (Advanced Configuration and Power Interface), recording the open and close timestamp and converting the timing to dots and dashes. After slamming to the required rhythm, you keep the lid open to see the character appear.

Why would want this? Well, you can now type the letter E by closing your laptop, instead of locking it. Maybe use it to send an emergency message while you’re being held by terrorists in a B-grade action movie. Otherwise, we think this is just an entertaining little hack that’s probably the product of quarantine induced boredom.

Morse code, otherwise known as CW, is still in surprisingly widespread use by ham radio operators, because it’s good at getting messages across intercontinental distances when signal conditions are bad and CW-only ham radio gear is cheap and easy to build yourself. We’ve also covered the Koch Method of learning CW, so don’t be afraid to dabble a bit during the quarantine.