Few things rival the usability and speed of a full-sized keyboard for text input. For decades, though, keyboards were mostly wired, which can limit where you use your favorite one. To address this, [KoStard]’s latest project uses an ESP32 to bridge a USB keyboard to BLE devices.

The ESP32-S3 packs a ton of fantastic functionality into its small size and low price—including USB-OTG support, which is key here. Taking advantage of this, [KoStard] programmed an ESP32-S3 to host a keyboard over its USB port while connecting via BLE to devices like cellphones.

There are some slick tricks baked in, too: you can pair with up to three devices and switch between them using a key combo. Some of you might be wondering how you can just plug a microcontroller into a keyboard and have it work. The truth is, it doesn’t without extra hardware. Both the keyboard and ESP32-S3 need power. The simplest fix is a powered USB hub: it can be battery-powered for a truly mobile setup, or use a wired 5V supply so you never have to charge batteries.

We love seeing a simple, affordable microcontroller extend the usefulness of gear you already have. Let us know in the comments about other hacks you’ve used to connect keyboards to devices never designed for them.

There’s a famous book that starts: “It is a truth universally acknowledged that a man in possession of a good e-ink display, must be in want of a weather station.” — or something like that, anyway. We’re not English majors. We are, however, major fans of this feline-based e-ink weather display by [Jesse Ward-Bond]. It’s got everything: e-ink, cats, and AI.

AI? Well, it might seem a bit gratuitous for a simple weather display, but [Jesse] wanted something a little more personalized and dynamic than just icons. With that in the design brief, he turned to Google’s Nano Banana API, feeding it the forecast and a description of his cats to automatically generate a cute scene to match the day’s weather.

That turned out to not be enough variety for the old monkey brain, so the superiority of silicon — specifically Gemini–was called upon to write unique daily prompts for Nano Banana using a random style from a list presumably generated by TinyLlama running on a C64. Okay, no, [Jesse] wrote the prompt for Gemini himself. It can’t be LLM’s all the way down, after all. Gemini is also picking the foreground, background, and activity the cats will be doing for maximum neophilia.

Aside from the parts that are obviously on Google servers, this is all integrated in [Jesse]’s Home Assistant server. That server stores the generated image until the ESP32 fetches it. He’s using a reTerminal board from SeedStudio that includes an ESP32-S3 and a Spectra6 colour e-ink display. That display leaves something to be desired in coloration, so on top of dithering the image to match the palette of the display, he’s also got a bit of color-correction in place to make it really pop.

If you’re interested in replicating this feline forecast, [Jesse] has shared the code on GitHub, but it comes with a warning: cuteness isn’t free. That is to say, the tokens for the API calls to generate these images aren’t free; [Jesse] estimates that when the sign-up bonus is used up, it should cost about fourteen cents a pop at current rates. Worth it? That’s a personal choice. Some might prefer saving their pennies and checking the forecast on something more physical, while others might prefer the retro touch only a CRT can provide.