Clotty The Custom Period Tracker Can, Of Course, Run DOOM

October 21, 2026 by Donald Papp 27 Comments

[kati]’s Clotty might run DOOM and game-ify the menstrual tracking process with a playful Tamagotchi-like aspect, but don’t let that distract you. It is, at its heart, a personal menstrual cycle tracking device that is defined as much by what it does do as what it doesn’t.

What doesn’t it do? Well, it will never quietly upload one’s menstrual tracking data to a remote server. Nor will it harvest, mishandle, disclose, or sell that same data. Shamefully, that alone sets it far apart from the wide range of period tracking services and apps out there. Also setting it apart is its cheerful lack of discretion. As [kati] puts it, she wanted Clotty’s design to scream “HELLO I AM A PERIOD TRACKING DEVICE” and at this she absolutely succeeded.

Clotty uses an RP2040, color LCD display, and a small variety of sensors built into a palm-sized, uterus-shaped PCB complete with touchpad ovaries. Right now it’s still in its early stages, and basically at the point that everything works hardware-wise and the essentials are there for software, but it’s still in active development. Keep an eye on Clotty’s GitHub repository for updates as features get fleshed out.

Of course, as [kati] observes, the core validity of a device can be defined by whether it can run DOOM, which of course Clotty can. You can find [kati]’s fork of RP2040-DOOM here.

[kati] has a knack for designing effective hardware that gamifies functions and incorporates a playfulness to the design that’s a delight to see. Take a moment to check out her Slightly Sentient D20 which is another excellent example of the kind of work she does.

Don’t Try This At Home, Transcranial Magnetic Stimulation Edition

October 7, 2026 by Tyler August 21 Comments

Transcranial magnetic stimulation is one of those things that seems too wacky to be true. Depression not responding to treatment? Let’s smack you upside the head with strong magnetic fields! As odd as it sounds, it’s actually very well studied and works often enough that it has been approved by regulatory agencies as real evidence based medicine.

It’s also now open source, thanks to the OpenTMS project by [Zach McGinty]. Though since its not approved by the FDA or your local authority, be very aware of [Zach]’s disclaimer that this is not a medical device and if you do build something based on the extensive data on his GitHub, you do so at your own risk.

He’s got plans for the coils that go next to your head — made of hollow copper pipe to carry coolant, just like the pros do it — and the power supply to pulse them with mind-altering amounts of electricity. That might be literal in this case, but it’s also a hefty power supply: a pair of microwave oven transformers, switched through IGBTs in a flyback configuration. We’re talking kiloamps here, so make sure you know what you’re about before you try putting that kind of power right next to your skull.

[Zach] did, and he’s still here. Though to be fair, we’re not sure if he’s a very good engineer or just very lucky. Given he’s isolated the IGBT gate controls with fiber optics, and seems to follow other best practices, we’re going to guess the former, but it might still be both.

Either way, this one is going firmly into the “don’t try this at home” bucket. Even so we’re happy to see more medicine go open source, be it assistive sip-and-puff pointing devices, or ESP32 electroencephalograms. If nothing else, it keeps the big boys on their toes, and that’s what hacking is all about.

An Open Heart Rate Monitor

September 14, 2026 by Jenny List 10 Comments

If you spend any time near a gym, you may be familiar with Bluetooth heart rate monitors — a small pack of electronics mounted on a strap round the chest which can relay heart rate data to an external logger or display. We’re pleased to see [Milos Rasic]’s project then, an open-source version of one of those monitors.

The heart rate capture is done by an AD8232, while the Bluetooth part is handled by a Seeed Studio XAIO ESP32 board. Power is provided by a single 3.7 V cell, with a boost converter to push that up to 5 V. The design omits a charge controller to keep things simple, so figuring out how to top off the cell is left as an exercise — no pun intended — for the user. Software is loaded through the Arduino IDE, which raises the possibility that other ESP32 CPUs could be supported with a bit of modification. All in all it’s a surprisingly simple project, and while the manufactured version is cheap enough it’s still very much worth having one that’s open source.

If you’d like to know more about his quest to develop open medical devices, check out the talk [Milos] gave on the intricacies of blood pressure monitoring earlier this year at Hackaday Europe.

Continue reading “An Open Heart Rate Monitor” →

Tech In Plain Sight: Meet The Robot That Does CPR

September 10, 2026 by Al Williams 24 Comments

Usually in Tech In Plain Sight, we talk about technology you probably see every day, even if you don’t notice it. But we hope you don’t get to see one of the latest crop of medical robots, such as the LUCAS chest compression system. If you watch the popular TV series “The Pitt”, though, you may have caught a glimpse of one of these medical marvels. They aren’t fiction. They are very real devices.

Calling them robots might be stretching the definition a little. They don’t roam the halls looking for patients. But once attached to someone in cardiac arrest, they can take over one of the most important — and physically demanding — parts of CPR: chest compressions.

Keep The Blood Moving

When someone’s heart stops pumping blood, time is critical. CPR doesn’t normally restart the heart on its own. Instead, chest compressions produce enough blood flow to keep oxygen reaching the brain and heart while rescuers work on the underlying problem and, when appropriate, use a defibrillator.

Doing that well is harder than it looks on television. Current American Heart Association guidelines call for adult chest compressions 100 to 120 times per minute, at least 5 cm deep but generally no deeper than 6 cm, while allowing the chest to recoil fully between compressions. Interruptions should be kept to a minimum.

That’s hard physical work. In fact, studies show compression depth begins to fall after only about 90 to 120 seconds, which is one reason CPR teams normally swap compressors every two minutes. But a robot doesn’t get tired.

Continue reading “Tech In Plain Sight: Meet The Robot That Does CPR” →

Tech In Plain Sight: Vacuum Blood Collection

August 24, 2026 by Zoe Skyforest 37 Comments

If you’re blessed enough that you haven’t had blood drawn in a while, you might not have thought much about the process. You might imagine that a needle goes in, a syringe is drawn back, and the venous blood is thusly collected. Indeed, it can be done that way.

However, there is an altogether niftier and more efficient method of fast blood collection for pathology testing. It’s all about using vacuum and smart design to ease the work of phlebotomists, while maintaining a sterile and safe environment.

Continue reading “Tech In Plain Sight: Vacuum Blood Collection” →

Smartphones And The Next Generation Of Hearing Aids

August 18, 2026 by Tom Nardi 31 Comments

If you don’t actually need one, you’d be forgiven for thinking a hearing aid just makes everything louder for the wearer. Especially since there are plenty of shady products out there which will do exactly that for just four easy payments of $29.99. But the reality is considerably more complex, as a proper hearing aid needs to be capable of selectively enhancing certain frequencies while squashing down others.

The technical challenges involved in pulling that off in a device small enough to fit inside the human ear and run off of a tiny battery are considerable — and while there’s undoubtedly been some degree of artificial price inflation going on over the years, there’s a reason proper hearing aids have been so much more expensive than their “As Seen on TV” counterparts. These same challenges are also why DIY and open source hardware hearing aids have struggled to gain much traction.

But over the last few years the situation has changed. In 2022 the United States Food and Drug Administration (FDA) established the framework by which hearing aids could be sold over the counter (OTC). Although they’re generally less capable than their prescription counterparts and not suitable for individuals with profound hearing loss, the wide commercial availability of OTC hearing aids has kicked off a competition between manufacturers to deliver more affordable devices.

That competition entered a new phase earlier this month when the FDA granted approval for Samsung’s Galaxy Earbuds to fall under the same category. This follows a similar decision made about Apple’s AirPods back in 2024. The two biggest players in the smartphone market being able to offer their earbuds as OTC hearing aids represents a unique value proposition. Not only are they priced for mass market consumption, but many individuals who would be interested in purchasing an OTC hearing aid will already own them and need only to enable the feature with a software update.

Given how different the situation is today than even just five years ago it’s worth asking just what qualifies as a over-the-counter hearing aid, and how the shifting definition of these devices can inform the community’s efforts to develop open hardware solutions.

Continue reading “Smartphones And The Next Generation Of Hearing Aids” →

Uninvasive EEG Interface Could Be Used To Play Games

August 14, 2026 by Zoe Skyforest 6 Comments

These days, most of us interface with our computing devices in the same old-fashioned ways—via keyboards, mice, and touchscreens. The idea of a more direct brain-to-machine interface remains appealing to many. [Ildar Rakhmatulin] and [Youssef El Abbass] have been working on just such a device, with an eye to using it for gaming.

The device is referred to as Octopus 16, so named because it combines sixteen EEG electrodes into a single compact package, along with the required common reference and ground. The contacts themselves are pogo pins, assembled into a coin-sized cluster. The device is strapped to the head, pushing the contacts against the scalp, and data from the electrodes is then siphoned off to a host machine via Bluetooth Low Energy. The EEG signals are picked up with a pair of Texas Instruments ADS131M08 ADCs, each with 8 channels, with a resolution of 24-bits to capture fine detail in whatever the brain is doing. An ESP32 microcontroller is responsible for grabbing the ADC output and trucking it out over Bluetooth.

The rig is designed for use with the PiEEG software platform. The team have experimented with the device, showing it off by using the EEG signals to detect an individual’s focus state and using that to feed into simple game environments.

Ultimately, what has been shown so far is not so different from the old Force Trainer toy, but the design might prove useful if you’re looking into doing EEG experiments on a budget. Just do your due diligence to make sure you’re getting more signal than noise out of those lovely 24-bit ADCs. Video after the break.

Continue reading “Uninvasive EEG Interface Could Be Used To Play Games” →