Super Simple Deadbuggable Bluetooth Chip

December 9, 2025 by Arya Voronova 21 Comments

We’re all used to Bluetooth chips coming in QFN and BGA formats, at a minimum of 30-40 pins, sometimes even a hundred. What about ten pins, with 1.27 mm pitch? [deqing] from Hackaday.io shows us a chip from WCH, CH571K, in what’s essentially a SO-10 package (ESSOP10). This chip has a RISC-V core, requires only three components to run, and can work Bluetooth through a simple wire antenna.

This chip is a RISC-V MCU with a Bluetooth peripheral built in, and comes from the CH57x family of WCH chips that resemble the nRF series we’re all used to. You get a fair few peripherals: UART, SPI, and ADC, and of course, Bluetooth 4 with Low Energy support to communicate with a smart device of your choice. For extra hacker cred, [deqing] deadbugs it, gluing all components and a 2.54 mm header for FTDI comms onto the chip, and shows us a demo using webBluetooth to toggle an LED through a button in the browser.

You need not be afraid of SDKs with this one. There’s Arduino IDE support (currently done through a fork of arduino_core_ch32) and a fair few external tools, including at least two programming tools, one official and one third-party. The chip is under a dollar on LCSC, even less if you buy multiple, so it’s worth throwing a few into your shopping cart. What could you do with it once received? Well, you could retrofit your smoke alarms with Bluetooth, create your own tire pressure monitors, or just build a smartphone-connected business card!

Build Yourself A Graphing Weather Display

December 8, 2025 by Lewin Day 7 Comments

These days, Internet connectivity is ubiquitous, so you can look up live weather data on just about any device around you. Regardless, [Jozerworx] wanted a simple, clean, independent weather display, and came up with this simple design.

The build is based on the Lilygo T5 EPD devboard, which combines an ESP32-S3 microcontroller with a nice 4.7-inch e-paper display. This display has the benefit that it only uses power when it’s being updated, making it particularly suitable to run off a battery for extended periods of time. Meanwhile, the ESP32 and its inbuilt Wi-Fi connectivity allow it to query the internet for updated weather forecasts. Weather data is sourced via the OpenWeather API, which [Jozerworx] notes comes with the caveat of requiring an API key. It’s a little fussy, but if you want good weather data, there are few easier ways to get it. The display shows a forecast for the next five days, while also showing graphs of ambient temperature and humidity along with useful information like the sunset and sunrise schedule.

Files are on Github for those eager to learn more. [Jozerworx] also notes that getting started with the display is particularly easy with the inclusion of a setup mode. This allows the display to act as a Wi-Fi access point with a web page that you use enter your home Wi-Fi connection details.

We’ve featured a great many charming weather displays over the years, too. If you’re working to plot, chart, or even predict the weather—don’t hesitate to show us your cool projects over on the tipsline!

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Standalone USB-PD Stack For All Your Sink Needs

December 6, 2025 by Arya Voronova 6 Comments

USB PD is a fun protocol to explore, but it can be a bit complex to fully implement. It makes sense we’re seeing new stacks pop up all the time, and today’s stack is a cool one as far as code reusability goes. [Vitaly] over on Hackaday.io brings us pdsink – a C++ based PD stack with no platform dependencies, and fully-featured sink capabilities.

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A Deep Dive Into Using PIO And DMA On The RP2350

November 30, 2025 by John Elliot V 7 Comments

Here’s a fun rabbit hole to run down if you don’t already have the RP2040/RP2350 PIO feather in your cap: how to serve data without CPU intervention using PIO and DMA on the RP2350.

If you don’t know much about the RP2040 or RP2350 here’s the basic run down: the original Raspberry Pi Pico was released in 2021 with the RP2040 at its heart, with the RP2350 making its debut in 2024 with the Pico 2. Both microcontrollers include a feature known as Programmed I/O (PIO), which lets you configure tiny state machines and other facilities (shift registers, scratch registers, FIFO buffers, etc) to process simple I/O logic, freeing up the CPU to do other tasks.

The bottom line is that you can write very simple programs to do very fast and efficient I/O and these programs can run separately to the other code running on your micro. In the video below, [piers] explains how it works and how he’s used it in his One ROM project.

This is the latest installment from [piers rocks] whose One ROM project we’ve been tracking since July this year when we first heard about it. Since then we’ve been watching this project grow up and we were there when it was only implemented on the STM32F4, when it was renamed to One ROM, and when it got its USB stack. Along the way [piers rocks] was on FLOSS Weekly Episode 850: One ROM To Rule Them All too.

Have you seen PIO being put to good use in other projects? Let us know in the comments, or on the tips line!

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A circuit sculpture designed to help you sleep.

Sweet Sound Sculpture Helps You Sleep Soundly

November 21, 2025 by Kristina Panos 9 Comments

Have trouble sleeping, or getting to sleep in the first place? You’ve no doubt heard of white noise machines, but know it would be much cooler to make your own. Enter Noise Maker, a DIY sound sculpture by [optimus103733], who wanted to learn something in the process of creating.

The best thing about this sound sculpture aside from the looks is that you can not only play five different sounds (e.g. birds, traffic, water, frog, white noise), you can mix them together into a rich but relaxing cacophony.

As you can probably see from the picture, Noise Maker is based on the ESP32 and uses an SD card module, an amplifier, and ~~five~~ six pots. Be sure to check out the pictures, because there are three layers of copper connections and a lot of careful bending to make it all come together. In the video after the break, you can hear it in action.

It seems [optimus103733] isn’t completely satisfied and wants to make a few improvements in the future, such as a voltage regulator, a power switch, and a timer to automatically stop playback once (we assume) sleep has come. Evidently the ESP32 struggles a little with mixing six audio sources, but hey, lesson learned.

Wait, why do we sleep in the first place?

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Wear This RISC V, RPN Calculator Watch For Maximum Nerd Cred

November 20, 2025 by Tyler August 12 Comments

Once upon a time, owning a calculator watch was the epitome of cool. Well, for a very specific subset of the population with our own definition of “cool” anyway. The only thing cooler than wearing a calculator watch? Making a calculator watch, of course! If you do it as part of developing your own SDK for a popular RISC V microcontroller, all the better. That’s what [Miroslav Nemecek] did with his Antcalc watch, which is one of the demo projects for the CH32Lib SDK, which is currently under development at version 0.35 as this is written.

It appears as though the solid core wire on the back of the homemade PCB is used to hold the watch band, a nice little hack.

As you might guess, CH32LibSDK is targeting the super-cheap CH32 series of RISC V microcontrollers. Perhaps because the SDK is so early in development, there’s not much documentation outside of the example projects. The examples are all worth looking at, but our tipster wanted us to cover the Antcalc calculator watch specifically.

The Antcalc watch uses the SOP16-packaged CH32V002A4M6 to drive a small OLED display while taking input in Reverse Polish Notation from a dozen small buttons. We’re not sure how the cool kids feel about RPN these days, but that’s got to be worth extra nerd cred. Using a RISC V chip doesn’t hurt in that department, either.

For something so small– 30 mm x 55 mm–it’s looks like a decent little calculator, with 10 registers holding a mantissa of 21 digits and exponents up-to +/-99 in binary coded decimal. Seven layers on the dozen-key input pad mean most of the scientific functions you could ask for are available, along with the ability to record and replay upto 10 macros. There are also ten memory slots, all of which go into the chip’s onboard flash so are non-volatile during a battery swap. (Of which many will be necessary, since this appears to run on a single coin cell.)

If you get bored of wrist-mounted calculating, you could always repurpose this microcontroller to play MOD files on your wrist. Some people couldn’t imagine ever getting bored by a wrist-mounted calculator, and just for them we have this teardown of a beautiful 1975 model and a this article on the history of the calculator watch.

Thanks to [James Bowman] for the tip.

Amiga? Arduino? AMeagerBall Gets The Uno Bouncing

November 19, 2025 by Tyler August 9 Comments

When the iconic “Boing Ball” first debuted 40 years ago, it was a wonder to behold. There was nothing like it in the home compuing world upto that time, and it showed that Commodore’s new “Amiga” was a powerhouse sure to last the test of time. Forty years later, the Amiga as we knew it then might not be with us anymore, but [Mark Wilson] is recreating its iconic demo on a microcontroller– but not just any microcontroller. “AMeagerBall” is an Arduino Uno exclusive, and it even tells the time.

Like the original “Boing Ball”, the demo is running at 320×240, though on a touch LCD shield instead of a CRT. Unlike some microcontrollers, the Uno doesn’t have the horsepower to just brute-force emulate a 1980s home computer, so [Mark] has had to recreate the boing ball from scratch. He’s not doing it with any graphics libraries, either. On the Uno that would be too slow, so [Mark] is driving the LCD directly to its appropriate registers, to stay close enough to the metal to make it work. That means if you’re going to try the code on his GitHub repository, you’ll need to be sure to use matching hardware or be prepared to port it.

One of the things about Amiga’s demo that was so impressive is that it hardly made use of the CPU, allowing the Workbench to be pulled up while the ball bounced. That’s not the case here, as the UNO doesn’t have any extra graphics chips. Still, [Mark] was able to squeeze enough horsepower out of everyone’s favourite ATmega to present us with an Amiga-styled clock– either analog, digital, or in the workbench title bar in that iconic blue-and-white. To keep the clock accurate, he’s squeezed an RTC module in, too. Lovely! The different clocks can be accessed via the touchscreen.

Oh, did we forget to mention that the touchscreen is implemented? This certainly stretches the hardware far enough to be considered a demo. If just a bouncing ball doesn’t work the UNO hard enough for you, try booting Linux.

This isn’t the first bouncing ball demo we’ve seen on a microcontroller: here are four of them bouncing in an ATtiny85.

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