Evolving RC Circuits

We are surrounded by evolving algorithms and AI models, and it feels like we have to evolve to them as well. Of course, the world itself is always evolving, and when we have to implement filtering circuits based on current environments it might not last all that long. [Saikarthik Ramakrishnan] realized that this phenomenon can easily apply to simple RC circuits, so why not make them adapt to the changing world itself? This is exactly what the Darwin Board is meant to do: act like an evolving simple RC circuit for whatever environment or signal you want gone.

RC circuits are normally considered to be relatively simple in the world of circuits; however, the real world isn’t always all that simple. This simple evolutionary algorithm implemented by [Saikarthik Ramakrishnan] attempts to apply similar principles used in other evolving models to the humble RC circuit. Based on an ESP32, the Darwin Board is a fairly simple model of 2040 possible combinations of genomes. Yes, each possible RC circuit is its own genome, which allows simple evolution from one to another based on current requirements.

You should certainly consider checking out the project’s GitHub repository here to try out the mutating circuit itself. While this project might complicate what is normally fairly simple, there is sometimes beauty in simplicity. So why not use a comically simple circuit for a smart home feature?

Your Multimeter Might Be Lying To You

Multimeters are indispensable tools when working on electronics. It’s almost impossible to build any but the most basic of circuits without one to test and troubleshoot potential issues, and they make possible a large array of measurement capabilities that are not easily performed otherwise. But when things start getting a little more complex it’s important to know their limitations, specifically around what they will tell you about circuits designed for high frequency. [watersstanton] explains in this video while troubleshooting an antenna circuit for ham radio.

The issue that often confuses people new to radio or other high-frequency projects revolves around the continuity testing function found on most multimeters. While useful for testing wiring and making sure connections are solid, they typically only test using DC. When applying AC to the same circuits, inductors start to offer higher impedance and capacitors lower impedance, up to the point that they become open and short circuits respectively. The same happens to transformers, but can also most antennas which often look like short circuits to ground at DC but can offer just enough impedance at their designed frequency to efficiently resonate and send out radio waves.

This can give some confusing readings, such as when testing to make sure that a RF connector isn’t shorted out after soldering it to a coaxial cable for example. If an antenna is connected to the other side, it’s possible a meter will show a short at DC which might indicate a flaw in the soldering of the connector if the user isn’t mindful of this high-frequency impedance. We actually featured a unique antenna design recently that’s built entirely on a PCB that would show this DC short but behaves surprisingly well when sending out WiFi signals.

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