Universal Bio-Electrical Signal Amplifier Makes Reading Body Signals Easy

August 26, 2021 by 18 Comments

The electrical signals emitted by the human body tell us a lot about what’s going on inside. But getting those signals inside your microcontroller is not straightforward: the voltages are too small for most ADCs, and the ever-present 50 or 60 Hz mains frequency makes it hard to discern subtle changes. Over at Upside Down Labs, [Deepak Kathri] developed a universal biosensor interface called the BioAmp EXG Pill to make all this a lot easier.

Its name refers to the fact that it can be used for several different bio-electrical sensing applications: ECG, EMG, EOG and EEG, which deal with signals coming from the heart, muscles, eyes and brain, respectively. To enable such flexibility, the board has connectors for two or three electrodes, as well as solder pads to mount resistors and capacitors to adjust the gain and bandwidth. An instrumentation amplifier increases the strength of the desired signal while rejecting noise and interference.

The form factor allows easy connection to electrodes on one side and a data acquisition system on the other. Measuring just 25.4 mm long and 10 mm wide, it should be easy to integrate into any type of biosensing gizmo you can come up with. [Deepak] has made several demo setups, showing him using the Pill with an Arduino to measure his heart rate, detect eye blinks, and even control a robot arm using his own arm muscles!

The EXG Pill is an evolution of an earlier EMG-only project. We’ve seen several great ECG and EEG projects before, but is the first time we’ve seen one amplifier that can do them all.

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FM Radio, The Choice Of An Old Generation

August 26, 2021 by 123 Comments

Had the pandemic not upended many of this summer’s fun and games, many of my friends would have made a trip to the MCH hacker camp in the Netherlands earlier this month. I had an idea for a game for the event, a friend and I were going to secrete a set of those low-power FM transmitters as numbers stations around the camp for players to find and solve the numerical puzzles they would transmit. I even bought a few cheap FM transmitter modules from China for evaluation, and had some fun sending a chiptune Rick Astley across a housing estate in Northamptonshire.

To me as someone who grew up with FM radio and whose teen years played out to the sounds of BBC Radio 1 FM it made absolute sense to do a puzzle in this way, but it was my personal reminder of advancing years to find that some of my friends differed on the matter. Sure, they thought it was a great idea, but they gently reminded me that the kids don’t listen to any sort of conventional broadcast radio these days, instead they stream their music, so very few of them would have the means for listening to my numbers stations. Even for me it’s something I only use for BBC Radio 4 in the car, and to traverse the remainder of the FM dial is to hear a selection of easy listening, oldies, and classical music. It’s becoming an older person’s medium, and it’s inevitable that like AM before it, it will eventually wane.

There are two angles to this that might detain the casual hacker; first what it will mean from a broadcasting and radio spectrum perspective, and then how it is already influencing some of our projects.

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Cash register keyboard

Custom Keyboard From A Cash Register

August 26, 2021 by 19 Comments

Having a high-quality mechanical keyboard is often a rite of passage in the computing world, with gamers and coders alike having strong opinions on the best devices. Even then, the standard keyboard layout can be substantially limiting, and often something a little extra and customizable is needed beyond even the highest-quality QWERTY keyboards. Reddit user [RonaldMcWhisky] was looking for a keyboard to use for macros, and discovered that it is possible to put cash register keyboards into service for any unique task.

Cash register keyboards have a number of advantages over a standard QWERTY design. They have big keys, the keys can be labeled, and the keys can be ordered in a way the user wants. The hardware is also cheap since cash registers are everywhere. Adapting one to work with a standard computer took a little bit of doing. Since this is /r/linuxhardware, you’re not going to find any Windows support here, but assuming you have the minimum system requirements of a Linux install to recognize the keyboard itself, a Python script can handle the events as the keys are pressed and interpret them in whatever way you want.

The actual hardware in this specific build was a Wincor Nixdorf TA85P — let us know in the comments if you’ve got one of those in your junk box. But the idea of using a cash register for a custom keyboard is interesting, and certainly a lot of work is already done for you if you don’t want to build your own custom keyboard from the ground up.

Hands-On: MNT Reforms The Laptop

August 26, 2021 by 120 Comments

When we met our contact from MNT in the coffee shop, he was quietly working away on his laptop. Jet black and standing thick it was like an encyclopedia that didn’t quite blend in with the sea of silver MacBook lookalikes on the surrounding tables. After going through all the speeds and feeds we eagerly got our 64 piece driver kit out to open it up and see what made this marvel tick, but when the laptop was turned over it became clear that no tools were needed. The entire bottom of the machine was a single rectangle of transparent acrylic revealing everything from sharp white status LEDs on the bare mainboard to individual 18650 LiFePO4 battery cells in a tidy row. In a sense that’s the summary of the entire product: it’s a real laptop you can use to get work done, and every element of it from design to fabrication is completely transparent.

a view of the inside of a MNT Reform laptop, showing screen and keyboard
The MNT Reform

The device pictured here is called the Reform and is designed and manufactured by MNT, a company in Berlin, Germany (note MNT stands for MNT, it’s not an acronym). The Reform is a fully open source laptop which is shipping today and available via distribution through Crowd Supply. If the aesthetic doesn’t make it clear the Reform is an opinionated product designed from the ground up to optimize for free-as-in-freedom: from it’s solid metal chassis to the blob-free GNU/Linux distribution running inside.

We’re here to tell you that we’ve held one, it’s real, and it’s very well built.

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Psion Organiser with a Pico memory pack.

Proto-PDA Regains Its Memory With The Help Of A Raspberry Pi Pico

August 26, 2021 by 2 Comments

Remember the Psion Organiser? If you do, chances are you were an early adopter, as the 8-bit pocket computer had its heyday in the mid-1980s. Things have come a long way since then, of course, but just how far is illustrated nicely by the fact that a Raspberry Pi Pico can stand in for the Psion’s original memory packs.

Like many of the early attempts at putting a computer in your pocket, the Psion II had removable modules, which were dubbed “Datapaks”. The earliest versions of the Datapaks were little more than an EPROM chip on a small PCB, and the technical limitations of the day plus the quirky way of addressing the memory made it possible for [Amen] to mimic a Datapak using a modern microcontroller.

The first version was a breakout board that extended out of the Datapak slot significantly, with a Pico, OLED display, SD card slot, and a bunch of pushbuttons. That prototype proved that the Pico was indeed fast enough to fool the Psion into thinking a legit Datapak was plugged in. [Amen] later refined the design by making a board that stuffs everything into the Datapak slot, with the exception of the OLED which still dangles out where it can be seen. He puts the faux memory to the test in the video below.

It’s great to see groundbreaking tech of yesteryear like the Psion being taken care of and returned to use. We’ve seen others try before; here’s a hack that uses a Pi to connect a Psion Organiser to the internet through its RS-232 serial port.

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Razer Mouse Grants Windows Admin Privileges

August 26, 2021 by 50 Comments

As the common saying goes, “all networked computers are vulnerable to exploits, but some networked computers are more vulnerable than others”. While not the exact wording from Animal Farm, the saying does have plenty of merit nonetheless. Sure, there are some viruses and issues with Linux distributions but by far most of the exploits target Windows, if only because more people use it daily than any other operating system. The latest Windows 10 exploit, discovered by [jonhat], is almost comically easy too, and involves little more than plugging in a mouse.

While slightly comforting in that an attacker would need physical access to the device rather than simple network access, it is very concerning how simple this attack is otherwise. Apparently plugging in a Razer mouse automatically launches Windows Update, which installs a driver for the mouse. The installation is run with admin privileges, and a Power Shell can be opened by the user simply by pressing Shift and right-clicking the mouse. While [jonhat] originally tried to let the company know, they weren’t responsive until he made the exploit public on Twitter, and are now apparently working on solving the issue.

Others have confirmed the exploit does in fact work, so hopefully there is a patch released soon that solves the issue. In the meantime, we recommend not allowing strangers to plug any devices into your personal computers as a general rule, or plugging in anything where its origins are unknown. Also remember that some attacks don’t required physical or network access at all, like this one which remotely sniffs keystrokes from a wireless keyboard with less than stellar security, also coincidentally built by Microsoft.

Can Metal Plated 3D Prints Survive 400,000 Volts?

August 25, 2021 by 12 Comments

It appears they can. [Ian Charnas] wanted his very own Thor Hammer. He wasn’t happy to settle on the usual cosplay methods of spray painting over foam and similar flimsy materials. He presents a method for nickel plating onto a 3D printed model, using conductive nickel paint to prepare the plastic surface for plating. In order to reduce the use of hazardous chemistry, he simplifies things to use materials more likely to be found in the kitchen.

As the video after the break shows, [Ian] went through quite a lot of experimentation in order to get to a process that would be acceptable to him. As he says, “after all, if something is worth doing, it’s worth over-doing” which is definitely a good ethos to follow. Its fairly hard to plate metals and get a good finish, and 3D printed objects are by their nature, not terribly smooth. But, the effort was well rewarded, and the results look pretty good to us.

But what about the 400 kV I hear you ask? Well, it wouldn’t be Thor’s hammer, without an ungodly amount of lightning flying around, and since [Ian] is part of a tesla coil orchestra group, which well, it just kinda fell into place. After donning protective chainmail to cover his skin, he walks straight into the firing line of a large pair of musical tesla coils and survives for another day. Kind of makes his earlier escapade with jet-powered roller skates look mundane by comparison.

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