You may or may not be reading this on a smartphone, but odds are that even if you aren’t, you own one. Well, possess one, anyway — it’s debatable if the locked-down, one-way relationships we have with our addiction slabs counts as ownership. [LuckyBor], aka [Breezy], on the other hand — fully owns his 4G smartphone, because he made it himself.
OK, sure, it’s only rocking a 4G modem, not 5G. But with an ESP32-S3 for a brain, that’s probably going to provide plenty of bandwidth. It does what you expect from a phone: thanks to its A7682E simcom modem, it can call and text. The OV2640 Arducam module allows it to take pictures, and yes, it surfs the web. It even has features certain flagship phones lack, like a 3.5 mm audio jack, and with its 3.5″ touchscreen, the ability to fit in your pocket. Well, once it gets a case, anyway.
A lot of hacks get inspired by science fiction. When that inspiration is taken from the boob tube or the silver screen, the visual design is largely taken care of by the prop department. If, on the other hand, one seeks inspiration from the written word– like [Math Campbell] did for his smart pocket watch inspired by The Diamond Age— the visuals are much more up to the individual hacker. Though no nanotechnology was involved in its creation, we think [Math] nailed the Victorian High-Tech vibe of [Neal Stephenson]’s cult classic.
The build itself is fairly simple: [Math] started with a Waveshare dev board that got him the 1.75″ round touch display, along with an ESP32-S3 and niceties such as a six-axis IMU, an RTC, microphone, speaker, and micro SD card reader. That’s quite the pocket watch! The current firmware, which is available on GitHub, focuses on the obvious use case of a very stylish watch, as well as weather and tidal display. Aside from the dev board, [Math] needed only to supply a battery and a case.
[Math] designed the case for the watch himself in Fusion360 before sending it off to be 3D printed in stainless steel. That might not be molecular-scale manufacturing like in the book, but it’s still amazing you can just do that. Ironically, [Math] is a silversmith and will be recreating the final version of the watch case in sterling silver by hand. We’d be tempted to include a door–making it a “hunter’s case” in pocket watch lingo–to protect that amoled display, but far be it for us to tell an artist how to do his work. If you’re not a silversmith, [Math] has stated his intent to add STLs to the GitHub repo, though they aren’t yet present at time of writing.
Thanks to [Math Campbell] for the tip! If you’ve got time on your hands after ticking done on a project, send us a tip and watch for it to appear here.
There are many solutions for remote control keyboards, be they Bluetooth, infrared, or whatever else. Often they leave much to be desired, and come with distinctly underwhelming physical buttons. [konkop] has a solution to these woes we’ve not seen before, turning an ESP32-S3 into a USB HID keyboard with a web interface for typing and some physical keyboard macro buttons. Instead of typing on the thing, you connect to it via WiFi using your phone, tablet, or computer, and type into a web browser. Your typing is then relayed to the USB HID interface.
The full hardware and software for the design is in the GitHub repository. The macro buttons use Cherry MX keys, and are mapped by default to the common control sequences that most of us would find useful. The software uses Visual Studio Code, and PlatformIO.
We like this project, because it solves something we’ve all encountered at one time or another, and it does so in a novel way. Yes, typing on a smartphone screen can be just as annoying as doing so with a fiddly rubber keyboard, but at least many of us already have our smartphones to hand. Previous plug-in keyboard dongles haven’t reached this ease of use.
Sometimes you need to use a computer and you don’t have a spare keyboard and mouse on hand. [KoStard] figured an iPhone could serve as a passable replacement interface device. To that end, he built an adapter to let the phone act as a wireless keyboard and mouse on just about any modern machine.
To achieve this, [KoStard] grabbed an ESP32-S3 development board, and programmed it to act as a USB HID device to any machine attached over USB. It then listens out for Bluetooth LE communications from an iPhone equipped with the companion app. The app provides an on-screen keyboard on the iPhone that covers everything including special keys, symbols, and punctuation. You can also take advantage of the iPhone’s quality capacitive touchscreen, which emulates a nicely-responsive trackpad, with two-finger taps used for right clicking and two-finger drags for scroll. Latency is nice and low courtesy of the direct Bluetooth LE connection.
It’s a nifty build that is particularly useful in oddball situations where you might want a keyboard and mouse. For example, [KoStard] notes it’s a great way to control a Smart TV without having to do ugly slow “typing” on an infrared remote. We’ve seen his work before, too—previously building an adapter to provide Bluetooth capability to any old USB keyboard. Video after the break.
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.
The generated image needs a little massaging to look nice on the Spectra6 e-ink display.
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.
With two cores at 240 MHz and about 8.5 MB of non-banked RAM if you’re using the right ESP32-S3 version, this MCU seems at least in terms of specifications to be quite the mini PC. Obviously this means that it should be capable of self-hosting its compiler, which is exactly what [Valentyn Danylchuk] did with the xcc700 C compiler project.
Targeting the Xtensa Lx7 ISA of the ESP32-S3, this is a minimal C compiler that outputs relocatable ELF binaries. These binaries can subsequently be run with for example the ESP-IDF-based elf_loader component. Obviously, this is best done on an ESP32 platform that has PSRAM, unless your binary fits within the few hundred kB that’s left after all the housekeeping and communication stacks are loaded.
The xcc700 compiler is currently very minimalistic, omitting more complex loop types as well as long and floating point types, for starters. There’s no optimization of the final code either, but considering that it’s 700 lines of code just for a PoC, there seems to be still plenty of room for improvement.
