close-up image of a philodendron houseplant with electrodes attached, connected to a robot arm holding a machete

(Mostly) Harmless Houseplant Wields Machete

In a straight fight between a houseplant and a human, you might expect the plant to be at a significant disadvantage. So [David Bowen] has decided to even the odds a little by arming this philodendron with a robot arm and a machete.

The build is a little short on details but, from the video, it appears that adhesive electrodes have been attached to the leaves of the recently-empowered plant and connected directly to analog inputs of an Arduino Uno.  From there, the text tells us that the signals are mapped to movements of the industrial robot arm that holds the blade.

It’s not clear if the choice of plant is significant, but an unarmed philodendron appears to be otherwise largely innocuous, unless you happen to be a hungry rodent. We hope that there is also a means of disconnecting the power remotely, else this art installation could defend itself indefinitely! (or until it gets thirsty, at least.) We at Hackaday welcome our new leafy overlords.

We have covered the capabilities of plants before, and they can represent a rich seam of research for the home hacker.  They can tell you when they’re thirsty, but can they bend light to their will?  We even held a Plant Communication Hack Chat in 2021.

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Universal Bio-Electrical Signal Amplifier Makes Reading Body Signals Easy

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.

UECG – A Very Small Wearable ECG

[Ultimate Robotics] has been working on designing and producing an extremely small ECG that can stream data real time.

Typical electrocardiogram equipment is bulky: miniaturization doesn’t do much for a hospital where optimizations tend to lean towards, durability, longevity, and ease of use. Usually a bunch of leads are strung between a conductive pad and an analog front end and display which interprets the data; very clearly identifying the patient as a subject for measurement.

uECG puts all this in a finger sized package. It’s no surprise that this got our attention at Maker Faire Rome and that they’re one of the Hackaday Prize Finalists. The battery, micro controller, and sampling circuitry are all nearly packed onto the board. The user has the option of streaming through BLE at 125 Hz or using a radio transceiver for 1 kHz of data. Even transmitting at these sample rates and filtering the signal of unwanted noise the device draws less than 10 mA.

The files to make the device are all on their page. Though they are planning to produce the boards in a small run which should be the best way to acquire one and start experimenting with this interesting data.

Giant LEDs, Ruby Lasers, Hologram Displays, And Other Cool Stuff Seen At Maker Faire Rome

Hackers from all over Europe descended upon Rome last weekend for the Maker Faire that calls itself the “European Edition”. This three-day event is one of the largest Maker Faires in the world — they had 27,000 school students from all over Italy and Europe attend on Friday alone.

This was held at Fiera Roma, a gigantic conference complex two train stops south of the Rome airport — kind of in the middle of nowhere. I was told anecdotally that this is the largest event the complex hosts but have no data to back up that claim. One thing’s for certain, three days just wasn’t enough for me to enjoy everything at the show. There was a huge concentration of really talented hardware hackers on hand, many who you’ll recognize as creators of awesome projects regularly seen around Hackaday.

Here’s a whirlwind tour of some of my favorites. On that list are a POV holographic display, giant cast-resin LEDs, an optical-pump ruby laser built out of parts from AliExpress, blinky goodness in cube-form, and the Italian audience’s appreciation for science lectures (in this case space-related). Let’s take a look.

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Hands-On: CCCamp2019 Badge Is A Sensor Playground Not To Be Mistaken For A Watch

Last weekend 5,000 people congregated in a field north of Berlin to camp in a meticulously-organized, hot and dusty wonderland. The optional, yet official, badge for the 2019 Chaos Communication Camp was a bit tardy to proliferate through the masses as the badge team continued assembly while the camp raged around them. But as each badge came to life, the blinkies that blossomed each dusk became even more joyful as thousands strapped on their card10s.

Yet you shouldn’t be fooled, that’s no watch… in fact the timekeeping is a tacked-on afterthought. Sure you wear it on your wrist, but two electrocardiogram (ECG) sensors for monitoring heart health are your first hint at the snoring dragon packed inside this mild-mannered form-factor. The chips in question are the MAX30001 and the MAX86150 (whose primary role is as a pulse sensor but also does ECG). We have high-res ADCs just waiting to be misused and the developers ran with that, reserving some of the extra pins on the USB-C connector for external devices.

There was a 10€ kit on offer that let you solder up some electrode pads (those white circles with gel and a snap for a solid interface with your body’s electrical signals) to a sacrificial USB-C cable. Remember, all an ECG is doing is measuring electrical impulses, and you can choose how to react to them. During the workshop, one of the badge devs placed the pads on his temples and used the card10 badge to sense left/right eye movement. Wicked! But there are a lot more sensors waiting for you on these two little PCBs.

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Sound Card ADCs For Electrocardiograms

Every few years, or so we’re told, [Scott] revisits the idea of building an electrocardiogram machine. This is just a small box with three electrodes. Attach them to your chest, and you get a neat readout of your heartbeat. This is a project that has been done to death, but [Scott]’s most recent implementation is fantastic. It’s cheap, relying on the almost absurd capability for analog to digital conversion found in every sound card, and the software is great. It’s the fit and finish that makes this project shine.

The hardware for this build is simply an AD8232, a chip designed to be the front end of any electrocardiogram. This is then simply connected to the microphone port of a sound card through a 1/8″ cable. For the exceptionally clever, there’s a version based on an op-amp. It’s an extraordinarily simple build, but as with all simple builds the real trick is in the software. That’s where this project really shines, with custom software with graphics, and enough information being displayed to actually tell you something.

We’ve seen a number of sound card ADCs being used for electrocardiograms in the past, including some from the Before Times; it makes sense, sound cards are the cheapest way to get a lot of analog data very quickly. You can check out [Scott]’s demo video out below.

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Toilet Seat Could Save Your Ass

Our morning routine could be appended to something like “breakfast, stretching, sit on a medical examiner, shower, then commute.” If we are speaking seriously, we don’t always get to our morning stretches, but a quick medical exam could be on the morning agenda. We would wager that a portion of our readers are poised for that exam as they read this article. The examiner could come in the form of a toilet seat. This IoT throne is the next device you didn’t know you needed because it can take measurements to detect signs of heart failure every time you take a load off.

Tracking heart failure is not just one test, it is a buttload of tests. Continuous monitoring is difficult although tools exist for each test. It is unreasonable to expect all the at-risk people to sit at a blood pressure machine, inside a ballistocardiograph, with an oximeter on their fingers three times per day. Getting people to browse Hackaday on their phones after lunch is less of a struggle. When the robots overthrow us, this will definitely be held against us.

We are not sure if this particular hardware will be open-source, probably not, but there is a lesson here about putting sensors where people will use them. Despite the low rank on the glamorous scale, from a UX point of view, it is ingenious. How can we flush out our own projects to make them usable? After all, if you build a badass morning alarm, but it tries to kill you, it will need some work and if you make a gorgeous clock with the numbers all messed up…okay, we dig that particular one for different reasons.

Via IEEE Spectrum.