Fully Submerge This Modernized PH Sensor

November 29, 2024 by Bryan Cockfield 17 Comments

There’s a school of thought that says you shouldn’t mess around with a solution that’s already working, but that’s never seemed to stop anyone in this community. When [Skye] was looking at the current state of connected pH meters they realized there was incredible room for improvement.

Called the Nectar Monitor, this pH meter is a more modern take on what is currently offered in this space. Open source and based on the ESP32, it’s accessible to most people with a soldering iron, fits into a standard project box, and includes other modern features like USB and WiFi connectivity. It can even measure conductivity and temperature. But the main improvement here is that unlike other monitors that can only be submerged temporarily, this one is designed to be under water for long time periods thanks to a specially designed probe and electrical isolation.

This design makes it an appealing choice for people with aquariums, hydroponic farms, or any other situation where constant monitoring of pH is extremely important to maintaining a balanced system. We’ve seen some unique takes on hydroponics before especially, including this build that moves the plants instead of the nutrient solution and this fully automated indoor garden.

2024 Business Card Challenge: Tiny MIDI Keyboard

June 6, 2024 by Bryan Cockfield 17 Comments

The progress for electronics over the past seven decades or so has always trended towards smaller or more dense components. Moore’s Law is the famous example of this, but even when we’re not talking about transistors specifically, technology tends to get either more power efficient or smaller. This MIDI keyboard, for example, is small enough that it will fit in the space of a standard business card which would have been an impossibility with the technology available when MIDI first became standardized, and as such is the latest entry in our Business Card Challenge.

[Alana] originally built this tiny musical instrument to always have a keyboard available on the go, and the amount of features packed into this tiny board definitely fits that design goal. It has 18 keys with additional buttons to change the octave and volume, and has additional support for sustain and modulation as well. The buttons and diodes are multiplexed in order to fit the IO for the microcontroller, a Seeed Studio Xiao SAMD21, and it also meets the USB-C standards so it will work with essentially any modern computer available including most smartphones and tablets so [Alana] can easily interface it with Finale, a popular music notation software.

Additionally, the project’s GitHub page has much more detail including all of the Arduino code needed to build a MIDI controller like this one. This particular project has perhaps the best size-to-usefulness ratio we’ve seen for compact MIDI controllers thanks to the USB-C and extremely small components used on the PCB, although the Starshine controller or these high-resolution controllers are also worth investigating if you’re in the market for compact MIDI devices like this one.

Continue reading “2024 Business Card Challenge: Tiny MIDI Keyboard” →

Is This The World’s Smallest Multichannel Voltmeter?

May 22, 2024 by Jenny List 8 Comments

The instrument which probably the greatest number of Hackaday readers own is likely to be the humble digital multimeter. They’re cheap and useful, but they’re single-channel, and difficult to incorporate into a breadboard project. If you’ve ever been vexed by these limitations then [Alun Morris] has just the project for you, in the world’s smallest auto-ranging multichannel voltmeter. It’s a meter on a tiny PCB with a little OLED display, and as its name suggests, it can keep an eye on several voltages for you.

At its heart is an ATtiny1614 microcontroller on a custom PCB, but for us the part we most like lies not in that but in the prototype version made on a piece of protoboard. There’s considerable soldering skill in bending surface mount components to your will on this material, and though these aren’t quite the smallest parts it’s still something that must have required some work under the magnifier.

All of the code and hardware details can be found in the GitHub repository, and for your viewing pleasure there’s a video showing it in action which we’ve placed below.

Continue reading “Is This The World’s Smallest Multichannel Voltmeter?” →

Ancient Instrument Goes Digital: The Digi-Gurdy

March 18, 2024 by Donald Papp 12 Comments

The hurdy-gurdy is a fascinating string instrument dating from sometime around the 10th century. There is an active community of modern enthusiasts, but one can’t simply walk into a music shop and buy one. That’s where [XenonJohn] and the Digi-Gurdy come in, bringing some nice features while maintaining all the important elements of the original.

The mechanical keys and crank of the Hurdy-Gurdy are preserved in this modern digital incarnation.

The hurdy-gurdy works by droning strings with a rotating wheel, and the player applies pressure to those strings via keys to play combinations of notes. Here’s a video demonstrating what it sounds like to play one, and one can see a conceptual resemblance to bagpipes, among other things.

The Digi-Gurdy is a modern electronic version that maintains the mechanical elements while sending MIDI signals over USB. It has options for line-out or headphone output. A thriving online community has shaped its development since its inception years ago.

We hope this leaves you wanting to know more because [XenonJohn] has loads of details to share. The main website at digigurdy.com is jam-packed with information about this instrument and its construction, and the project page on Hackaday.io has more nitty-gritty design details and source files for those who crave hardware specifics.

If [XenonJohn]’s name sounds familiar, it’s because we’ve admired his work on DIY self-balancing vehicles over the years. He also submitted an earlier version as an entry into the Hackaday Prize. His careful attention to detail shines through. Check out the two videos (embedded just below the page break): the first demonstrates the Digi-Gurdy, and the second shows off the construction and insides. You’d think a MIDI hurdy-gurdy would be unique, but, actually, we’ve seen more than one.

Continue reading “Ancient Instrument Goes Digital: The Digi-Gurdy” →

Hackaday Links: January 7, 2024

January 7, 2024 by Dan Maloney 27 Comments

Oh, perfect — now our cars can BSOD. At least that’s how it looks from a forum post showing a Blue Screen of Death on a Ford Mustang Mach E, warning that an over-the-air software update failed, and now the car can’t be driven. The BSOD includes a phone number to reach Ford’s Customer Relationship Center and even presents a wall of text with specific instructions to the wrecker driver for loading the bricked vehicle onto a flatbed. Forum users questioned the photo’s veracity, but there are reports of other drivers getting bricked the same way. And we’ve got to point out that even though this specific bricking happened to an EV, it could just have easily happened to an ICE vehicle too; forum members were particularly prickly about that point. It would be nice if OTA software updates on vehicles could always roll back to the previous driveable state. Still, we suppose that’s not always possible, especially if memory gets corrupted during the update. Maybe the best defense against a bricked vehicle would be to keep a beater around that doesn’t need updates to keep running.

Continue reading “Hackaday Links: January 7, 2024” →

Compose Any Song With Twelve Buttons

March 29, 2023 by Bryan Cockfield 15 Comments

Limitations placed on any creative process often paradoxically create an environment in which creativity flourishes. A simple overview of modern pop, rock, or country music illustrates this principle quite readily. A bulk of these songs are built around a very small subset of music theory, often varying no more than the key or the lyrics. Somehow, almost all modern popular music exists within this tiny realm. [DeckerEgo] may have had this idea in mind when he created this tiny MIDI device which allows the creation of complex musical scores using a keyboard with only 12 buttons.

The instrument is based around the Adafruit MacroPad, which is itself built on the RP2040 chip. As a MIDI device, it needs to be connected to a computer running software which can support MIDI instruments, but once its assembled and given its firmware, it’s ready to rock. A musician can select one of any number of musical scales to operate within, and the 12 keys on the pad are mapped to the 12 chromatic notes within that scale. It can also be used to generate drum tracks or other backing tracks to loop before being used to create melodies as well.

[DeckerEgo] took a bit of inspiration from an even simpler macro pad we featured before which is based around the idea that a shockingly high number of songs use the same four chords. His macro pad includes creation of chord progressions as well, but expands on that idea to make more complete compositions possible. And, for those looking to build their own or expand on this project, he has also made all of the source code available on his GitHub page.

Continue reading “Compose Any Song With Twelve Buttons” →

A RPI HAT For Synchronized Measurements

September 15, 2022 by Dave Rowntree 17 Comments

A team from the Institute for Automation of Complex Power System (ACS) at RWTH Aachen University have been working for a while on the analysis of widely distributed power systems. In a drive to move away from highly specialised (and expensive) electronics platforms, they have produced some instrumentation designed to operate with the Raspberry Pi platform, and an open source software stack. They call the platform the SMU (Synchronised Measurement Unit.) The SMU consists of a HAT sitting on an RPi3, inside a 3D printed box that is intended to attach to a DIN rail. After all, this is supposed to be an industrial platform.

Hardware wise, the star of the show is the Texas Instruments ADS8588S which is a 16-bit 8-channel simultaneous sampling ADC. This is quite a nice device, with 200 kSPS throughput and a per-channel programmable front end, packaged in a hacker-friendly 64-pin QFP. What makes this project interesting however, is how they solved the problem of controlling the sampled data acquisition and synchronisation.

1-PPS and BUSY edges converted to levels, then OR’d to trigger the DMA

By programming the ADC into byte-parallel mode, then using the BCM2837 Secondary Memory Interface (SMI) block together with the DMA, samples are transferred into memory with minimal CPU overhead. An onboard U-Blox Max-M8 GNSS module provides a 1PPS (top of second pulse) signal, which is combined with the ADC busy signal in a very simple manner, enabling both sample rate control as well as synchronisation between multiple units spread out in an installation. They reckon they can get synchronisation to within 180 ns of top-of-second, which for measuring relatively slow-changing power systems, should be enough. The HAT PCB was created in KiCAD and can be found in the SMU GitHub hardware section, making it easy to modify to your needs, or at least adjust the design to match the parts you can actually get your hands on.

Continue reading “A RPI HAT For Synchronized Measurements” →