Hackaday Newsletter 0x95

This is why I still love reading Hackaday. [HACKADAY]() Big Chemistry: Hydrofluoric Acid [Read Article Now»]( Sometimes It’s the Little Things By [Elliot Williams]( I had one of those why-didn’t-I-think-of-it moments this week, reading [this article about multiplexing I2C on the ESP32 microcontroller](. The idea is so good, and so simple, that it’s almost silly that it’s not standard hacker practice. And above all, it actually helps solve a problem that I’ve got. This is why I read Hackaday every day. I2C is great in that it lets you connect up multiple devices to a pair of wires using a very bus architecture. Every device has its own address, the host calls them out, and hopefully all other devices keep quiet while just the right one responds. But what happens when you want to use a few of the same sensors, where each IC has the same address? The usual solution is to buy a multiplexer chip. But many modern microcontrollers, like the ESP32, have an internal multiplexer setup that lets you map the pins with the dedicated hardware peripherals, usually at initialization time. Indeed, I’ve been doing it as an “init” task so long, I never thought to do it otherwise. But that’s exactly the idea behind [BastelBaus]’s hack – if you dynamically reassign the pins, you can do the I2C multiplexing with the chip you’ve got. This should probably work for any other chips that have multiple assignable pins for hardware peripherals as well. Cool idea, but really simple. Why hadn’t I ever thought of it? I think it’s because I’ve always had this init / mainloop schema in my mind, which for instance the Arduino inherited and formalized in its setup() and loop() functions. Pin mappings go in the init section, right? So what this hack really amounts to, for me, is a rethinking of what’s static and what’s dynamic. It’s always worth questioning your assumptions, especially when you’re facing a problem that requires a creative solution. Sometimes limitations are only in your mind. From the Blog --------------------------------------------------------------- [Ethernet For Hackers: Equipment Exploration]( By [Arya Voronova]( Arya digs into Ethernet setups, especially Power over Ethernet. [Read more »]( [The White House Memory Safety Appeal is a Security Red Herring]( By [Maya Posch]( Is the problem really memory safety? Or is that just the hammer looking for a nail? [Read more »]( [Ask Hackaday: What If You Did Have a Room Temperature Superconductor?]( By [Al Williams]( With all the speculative science going on, Al asks what if it were true. [Read more »]( [Hackaday Podcast]( [Hackaday Podcast Episode 260: KiCad 8, Two Weather Stations, and Multiple I2Cs]( By [Hackaday Editors]() What happened last week on Hackaday? The Podcast will get you up to speed. [Read more »]( If You Missed It --------------------------------------------------------------- [The Latest Advancements in Portable N64 Modding]( [KiCad 8 Makes Your Life Better Without Caveats]( [Avoid I2C Address Conflicts On ESP32 By Pin Muxing]( [Making a Dye-Sensitized Solar Cell Is Almost DIY-able]( [A “Full” Keyboard for $5*]( [ThinkPad X1 Carbon Turned USB Device Through Relentless Digging]( [Hackaday]() NEVER MISS A HACK [Share]( [Share]( [Share]( [Terms of Use]( [Privacy Policy]( [Hackaday.io]( [Hackaday.com]( This email was sent to {EMAIL} [why did I get this?]( [unsubscribe from this list]( [update preferences]( Hackaday.com · 61 S Fair Oaks Ave Ste 200 · Pasadena, CA 91105-2270 · USA