On paper, electricity behaves in easy-to-understand, predictable ways. That’s mostly because the wires on the page have zero resistance and the switching times are actually zero, whereas in real life neither of these things are true. That’s what makes things like switch-mode power supplies (SMPS) difficult to build and troubleshoot. Switching inductors and capacitors tens or hundreds of thousands of times a second (or more) causes some these difficulties to arise when these devices are built in the real world. [FesZ Electronis] takes a deep dive into some of the reasons these difficulties come up in this video.

The first piece of electronics that can generate noise in an SMPS are the rectifier diodes. These have a certain amount of non-ideal capacitance as well as which causes a phenomenon called reverse current, but this can be managed by proper component choice to somewhat to limit noise.

The other major piece of silicon in power supplies like this that drives noise are the switching transistors. Since the noise is generally caused by the switching itself, there is a lot that can be done here to help limit it. One thing is to slow down the amount of time it takes to transition between states, limiting the transients that form as a result of making and breaking connections rapidly. The other, similar to selecting diodes, is to select transistors that have properties (specifically relating to inherent capacitances) that will limit noise generation in applications like this.

Of course there is a lot more information as well as charts and graphs in [FesZ]’s video. He’s become well-known for deep dives into practical electrical engineering topics like these for a while now. We especially like his videos about impedance matching as well as a more recent video where he models a photovoltaic solar panel in SPICE.

Last year, we’ve featured a super cheap smart ring – BLE, accelerometer, heart sensor, and a battery, all in a tiny package that fits on your finger. Back when we covered it, we expected either reverse-engineering of stock firmware, or development of a custom firmware outright. Now, you might be overjoyed to learn that [Wesley Ellis] has written a Python client for the ring’s stock firmware.

Thanks to lack of any encryption whatsoever, you can simply collect the data from your ring, no pairing necessary, and [Wesley]’s work takes care of the tricky bits. So, if you want to start collecting data from this ring right now, integrate it into anything you want, such as your smart home or exoskeleton project, this client is enough. A few firmware secrets remain – for instance, the specific way that the ring keep track of day phases, or SPO2 intricacies. But there’s certainly enough here for you to get started with.

This program will work as long as your ring uses the QRing app – should be easy to check right in the store listing. Want to pick up the mantle and crack open the few remaining secrets? Everything is open-source, and there’s a notepad that follows the OG reverse-engineering journey, too. If you need a reminder on what this ring is cool for, here’s our original article on it.

In the near future, imagine a world where your health is continuously monitored, not through bulky devices but through an invisible graphene tattoo. Developed at the University of Massachusetts Amherst, these tattoos could soon detect a range of health metrics, including blood pressure, stress levels, and even biomarkers of diseases like diabetes. This technology, though still in its infancy, promises to revolutionize how we monitor health, making it possible to track our bodies’ responses to everything from exercise to environmental exposure in real-time.

Graphene, a single layer of carbon atoms, is key to the development of these tattoos. They are flexible, transparent, and conductive, making them ideal for bioelectronics. The tattoos are so thin and pliable that users won’t even feel them on their skin. In early tests, graphene electronic tattoos (GETs) have been used to measure bioimpedance, which correlates with blood pressure and other vital signs. The real breakthrough here, however, is the continuous, non-invasive monitoring that could enable early detection of conditions that usually go unnoticed until it’s too late.

While still requiring refinement, this technology is advancing rapidly. Graphene still amazes us, but it’s no longer just science fiction. Soon, these tattoos could be a part of everyday life, helping individuals track their health and enabling better preventative care. Since we’re hackers out here –  but this is a far fetch – combining this knowledge on graphene production, and this article on tattooing with a 3D printer, could get you on track. Let us know, what would you use graphene biosensors for?

Original photo by engin akyurt on Unsplash