Is That An ESP32 On Your Wrist?

May 22, 2020 by Al Williams 38 Comments

What could you do with a dual-core 240 MHz ESP32 that supports Arduino-style programming, with 16 MB of flash, 8 MB of PSRAM, and 520 k of RAM? Oh, let’s throw in a touchscreen, an accelerometer, Wifi, and Bluetooth. Besides that, it fits on your wrist and can show the time? That’s the proposition behind Lilygo T Watch 2020. If it sounds like a smartwatch, it is. At around $25 –and you can snag the hardware from a few different places — it is not only cheaper than the latest flagship smartwatch, but it is also infinitely more hackable.

OK, so the screen is only 1.54″, but then again, it is a watch. If Arduino isn’t your thing, you can use anything else that supports the ESP32 like Micropython or even Scratch. There are variants that have LoRA and GPS, at slightly higher prices. You can also find ones with heart rate monitors and other features.

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Self-Shutting Face Mask Is Hacker’s Delight

May 19, 2020 by Moritz v. Sivers 28 Comments

Most of us currently have to deal with wearing face masks in our daily life. An experience that is not entirely pleasurable as it is more difficult to breathe under the mask and can become hot after a while. In addition, you have to take off the mask whenever you want to eat or drink. [DesignMaker] has attempted to solve these problems by creating a mask with an opening that shuts automatically when other people are nearby.

While homemade masks are usually made from fabric [DesignMaker]’s version is much more to a hacker’s taste and includes 3D-printed parts, an Arduino Nano, PIR sensors, an SG90 servo, and some Neopixels. [DesignMaker]’s background in industrial design certainly helped him when modeling the mask as it looks just plain awesome.

His goal was to use PIR sensors to detect when a person is moving nearby. The servo then shuts an opening located at the mouth part of the mask. However, he soon found out that the mask often shuts when nobody is around. The reason is that the sensor can be triggered by ambient IR radiation when it is moving by itself. In the end [DesignMaker] decided that having the mask shut when you are moving is not a bug, it’s a feature.

Of course, the mask is just a prop and should not be used as protective equipment. As shown in the video below, also the false triggering of the PIR sensors can be annoying at times. But [DesignMaker] is already thinking of improvements like having the mask properly sealed with fabric or replacing the PIR sensors by a camera with face detection.

If you want to learn how to sew a proper fabric face mask have a look here. It’s a lot less ridiculous, but a lot more effective. You can’t have everything.

Video after the break.

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PCB Jewelry Never Looked So Good

May 16, 2020 by Orlando Hoilett 8 Comments

[Gautchh] wanted to make something nice for his girlfriend. Being the DIY enthusiast he is, he thought a hand-made gift would resonate with her better than something he could pick up from the store. Enter NeckLight, a glow in the dark PCB necklace. He was first inspired by another project he ran across on Instructables, then decided to put his own little spin on the design. It’s cool how that works. Interestingly enough, it was his first time using Fusion 360, but you probably wouldn’t know that if you took a look at the results.

Aside from soldering, the trickiest part of this project was trying to get the LED intensities just right. [Gautchh] found the best way to do this was experimentally by testing each LED color with a series of resistors. He wanted to ensure he could get the color intensity and the LED current just right. Finally, with a touch of acetone, he was done (though he might want to try some alternatives to acetone next time).

[Gautchh] also thinks that this project would be a really nice way for beginners to learn surface mount (SMD) soldering. We’ve seen a few cool SMD LED projects before. Who could forget those competitive soldering challenges over at DEF CON?

Anyway. Thanks, [Gautchh]. We hope your girlfriend, and your dog, enjoyed their gifts.

A Smart Bandage For Monitoring Chronic Wounds

May 12, 2020 by Orlando Hoilett 4 Comments

Here at Hackaday, we’re always enthralled by cool biohacks and sensor development that enable us to better study and analyze the human body. We often find ourselves perusing Google Scholar and PubMed to find the coolest projects even if it means going back in time a year or two. It was one of those scholarly excursions that brought us to this nifty smart bandage for monitoring wound healing by the engineers of FlexiLab at Purdue University. The device uses an omniphobic (hydrophobic and oleophobic) paper-based substrate coupled with an onboard impedance analyzer (AD5933), an electrochemical sensor (the same type of sensor in glucometers) for measuring uric acid and pH (LMP91000), and a 2.4 GHz antenna for wirelessly transmitting the data (nRF24L01). All this is programmed with an Arduino Nano. They even released their source code.

To detect uric acid, they used the enzyme uricase, which is very specific to uric acid and exhibits low cross-reactivity with other compounds. They drop cast uric acid onto a silver/silver chloride electrode printed on the omniphobic paper. Similarly, to detect pH, they drop cast a pH-responsive polymer called polyaniline emeraldine salt (PANI-ES) between two separate silver/silver chloride electrodes. All that was left was to attach the electrodes to the LMP91000, do a bit of programming, and there they were with their own electrochemical sensor. The impedance analyzer was a bit simpler to develop, simply attaching un-modified electrodes to the AD5933 and placing the electrodes on the wound.

The authors noted that the device uses a much simpler manufacturing process compared to smart bandages published by other academics, being compatible with large-scale manufacturing techniques such as roll-to-roll printing. Overcoming manufacturing hurdles is a critical step in getting your idea into the hands of consumers. Though they have a long way to go, FlexiLab appears to be on the right track. We’ll check back in every so often to see what they’re up to.

Until then, take a look at some other electric bandage projects on Hackaday or even make your own electrochemical sensor.

A Backpack That Measures Your Heart Rate

May 11, 2020 by Orlando Hoilett 4 Comments

It’s interesting to see the different form-factors that people utilize for their portable biometric sensors. We’re seeing heart rate monitors and other biometric sensors integrated into watches, earbuds, headbands, sports bras, and all sorts of other garments and accessories. [Gabi] took an intriguing approach, integrating an electrocardiogram (ECG) into a backpack. This type of heart rate project is pretty popular here on Hackaday, so it was great running across [Gabi’s] design during our daily perusing for the new and exciting.

[Gabi] used an Adafruit FLORA, a BLE module, an ECG sensor from Bitalino, a few other ancillary components, and, of course, a backpack. We appreciate that she walked us through the list of stumblingblocks she came across and how she got around them. So much of the time in our excitement to share our projects we remove the gory details and only present the finished project when really, we learn most from all the things that didn’t work more so than the things that did. Finally, [Gabi] walks through the intricacies of the threading and the particular placement of the snap connectors to attach the circuit to the ECG electrodes. Things get pretty tricky, but luckily [Gabi] documents her project pretty meticulously with schematics, pictures, and early notice of pitfalls.

[Gabi] made sure to remind her readers that this is a prototype, not a medical device. She also brought up electrical safety. Biometric devices such as ECGs need to include a strict set of isolation circuits to prevent potential harm to the user. Fortunately, there are a few well-characterized methods to accomplish this.

So thanks for a really cool project, [Gabi], and to our readers, why not enjoy some of our other ECG projects while you’re at it?

Halloween Costume Turned Positive Pressure Suit

May 9, 2020 by Tom Nardi 31 Comments

As a general rule, you probably shouldn’t be getting your Personal Protective Equipment (PPE) from the party store. But these are exceptional times, and rather than potentially depriving medical professionals the equipment they so desperately need on the front lines, the team at [Robots Everywhere] has been looking into improvised PPE. We’re not sure things are at the point where you would need to don this DIY Positive Pressure Suit (PAPR), but it’s certainly an interesting look at what’s possible when you think outside the box.

At the most basic level, a PAPR is a mostly air-tight garment that is continuously pumped full of filtered air. As long as the pressure inside the suit is higher than outside, there’s no way airborne bacteria and viruses can get in without traveling through the filter first.

For this project, the folks at [Robots Everywhere] took an inflatable astronaut costume and replaced the dinky original air pump with a much larger 12 V unit designed for inflating air beds. Upgrading the pump not only increased the internal air pressure of the suit, but also made it easier to add a HEPA filter to the inlet. As long as the suit is inflated and there are no leaks in the hose, the wearer will be surrounded by a bubble of filtered air.

Presumably, you don’t want to be tethered to the wall though, so the write-up briefly touches on how the pump system can be made more mobile with the addition of an RC-style battery pack. With the pump and batteries secured in a pouch attached to the suit, the wearer is free to venture outside the confines of their self-isolation bunker and go about their dystopian daily business.

A getup like this might seem a bit excessive, but with so many folks desperate for information on homemade protective gear, we aren’t passing any judgment. The team says you can modify a cheap painter’s suit in much the same way, but frankly, that doesn’t sound nearly as fun to us.

[Thanks to Aron for the tip.]

Touch-Typing On Fingertips? Prototype Says It Could Work

May 9, 2020 by Donald Papp 11 Comments

The fingertips are covered in touch sensors, each intended to be tapped by the thumbtip of the same hand.

Touch-typing with thumbs on a mobile phone keyboard is a pretty familiar way to input text, and that is part of what led to BiTipText, a method of allowing bimanual text input using fingertips. The idea is to treat the first segments of the index fingers as halves of a tiny keyboard, whose small imaginary keys are tapped with the thumbs. The prototype shown here was created to see how well the concept could work.

The prototype hardware uses touch sensors that can detect tap position with a high degree of accuracy, but the software side is where the real magic happens. Instead of hardcoding a QWERTY layout and training people to use it, the team instead ran tests to understand users’ natural expectations of which keys should be on which finger, and how exactly they should be laid out. This data led to an optimized layout, and when combined with predictive features, test participants could achieve an average text entry speed of 23.4 words per minute.

Judging by the prototype hardware, it’s understandable if one thinks the idea of fingertip keyboards may be a bit ahead of its time. But considering the increasingly “always on, always with you” nature of personal technology, the goal of the project was more about investigating ways for users to provide input in fast and subtle ways. It seems that the idea has some merit in principle. The project’s paper can be viewed online, and the video demonstration is embedded below.

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