Touchscreen Makes For A Neat Wavetable Synth

August 15, 2021 by Lewin Day 8 Comments

A popular tool in chiptune software like LSDJ allows the user to draw a waveform and use it as the basis for a wavetable synth. It’s fun and it can produce some great bleeps and bloops. [Kevin] has created a similar tool using an Arduino and a touchscreen.

The build is based on the Arduino Uno, the humble mainstay of the Arduino line. It’s hooked up to an ILI9488 color touchscreen display, which acts as the primary user interface. Using a stylus, or presumably a finger, the user can draw directly on the screen to specify the desired waveform for the synth to produce. The Arduino reads the step-by-step amplitude values of the drawn waveform and uses them to synthesize audio according to MIDI messages received over its serial port. Audio output is via PWM, as is common in low-cost microcontroller projects.

It’s a fun build and we’re sure [Kevin] learned plenty about wavetable synthesis along the way. We’ve seen his work on other Arduino synthesis projects before, too! Video after the break.

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Arduino Finds Treasure

August 12, 2021 by Bryan Cockfield 6 Comments

A beach is always a relaxing summer vacation destination, a great place to hang out with a drink and a book or take a swim in the ocean. For those who need a more active beach-going activity with an electronics twist, though, metal detecting is always a popular choice too. And, of course, with an Arduino and some know-how it’s possible to build a metal detector that has every feature you could want from even a commercial offering.

This build comes to us from [mircemk] who built this metal detector around an Arduino Nano and uses a method called induction balance detection to find metal. Similar to how radar works, one coil sends out a signal and the other listens for reflections back from metal objects underground. Building the coils and determining their resonant frequency is the most important part of this build, and once that is figured out the rest of the system can be refined and hidden treasure can easily be unearthed.

One of the more interesting features of this build is its ability to discriminate between ferrous and non-ferrous metals, and it can detect large metal objects at distances of more than 50 cm. There are improvements to come as well, since [mircemk] plans to increase power to the transmission coil which would improve the range of the device. For some of [mircemk]’s other metal detectors, be sure to check out this one which uses a smartphone to help in the metal detection process.

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Pinewood Derby Scale Measures CG

July 29, 2021 by Al Williams 23 Comments

If you suffer from nostalgia, you might remember carving a block of wood into a car, adding some wheels, and racing it against other contestants in a pinewood derby. Today’s derby is decidedly high tech though, and we were impressed with this car scale that also figures out the car’s center of gravity.

Based on an Arduino, of course, along with a pair of HX711 load cells. Why a pair? That’s how the device measures the center of gravity is by weighing the front and rear of the car separately.

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Clever PCB Brings Micro USB To The Arduino Uno

July 21, 2021 by Tom Nardi 38 Comments

Even with more and more devices making the leap to USB-C, the Arduino Uno still proudly sports a comparatively ancient Type-B port. It wouldn’t be a stretch to say that many Hackaday readers only keep one of these cables around because they’ve still got an Uno or two they need to plug in occasionally.

Looking to at least move things in the right direction, [sjm4306] recently set out to create a simple board that would let him mount a micro USB connector in place of the Uno’s original Type-B. Naturally there are no components on the PCB, it simply adapts the original through-hole footprint to the tight grouping of surface mount pads necessary to mount a female micro USB port.

The design is straightforward, but as [sjm4306] explains in the video below, there’s actually more going on here than you might think. Looking to avoid the premium he’d pay to have the board house do castellated holes, he cheated the system a bit by having the board outline go right through the center of the standard pads.

Under a microscope, you can see the downside of this approach. Some of the holes got pretty tore up as the bit routed out the edges of the board, with a few of them so bad [sjm4306] mentions there might not be enough of the pad left to actually use. But while they may not be terribly attractive, most of them were serviceable. To be safe, he says anyone looking to use his trick with their own designs should order more boards than they think they’ll actually need.

Of course you could go all the way and retrofit the Uno with a USB-C port, as we’ve seen done with devices in the past. But the latest-and-greatest USB interface can be a bit fiddly, especially with DIY gadgets, so we can’t blame him for going with the more reliable approach.

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One Giant Button To Mute Them All

July 20, 2021 by Kristina Panos 3 Comments

The second round of this year’s Hackaday Prize is coming to a close, and we asked you to come up with ways of refreshing work-from-home life. Well here’s one we probably all could use — a large emergency mute button that can also turn off video with an extra click. You know, in case your kid or your roommate decides to walk around in their birthday suit.

[Colin Russell-Conway]’s software-agnostic mute button uses a Seeeduino Xiao and rotary encoder, plus three momentaries that give it a second function as a media controller. Two chunks of LED strip go blinky blinky when the mute is on, and are otherwise solidly lit and color-coded by videoconference type — blue for Zoom and Starleaf, green for Webex, and purple for Teams.

The companion app that [Colin] created is using the Windows Management Instrumentation (WMI) to check which program is control of the microphone. Whenever the mute button is pressed, the app makes note of the current program in focus, switches to the active videoconference, mutes it, and then switches back to reddit or twitch or whatever you had in focus when the kid started screaming for you from the bathroom. Check out the demo after the break.

Some of us like to celebrate a little when videoconferences are over. For those people, there is the pull-chain exit.

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MIDI Mouse Makes Marvelous Music

July 18, 2021 by Adam Zeloof 5 Comments

It’s an old misconception that digital musicians just use a mouse and keyboard for their art. This is often far from the truth, as many computer music artists have a wide variety of keyboards/synths, MIDI controllers, and “analog” instruments that all get used in their creative process. But what if one of those instruments was just a mouse?

Well, that must have been what was going through [kzra]’s mind when he turned an old ps/2 roller ball mouse into an electronic instrument. Born out of a love for music and a hate for waste, the mouse is a fully functional MIDI controller. Note pitch is mapped to the x-coordinate of the pointer, and volume (known as velocity, in MIDI-speak) is mapped to the y-coordinate. The scroll wheel can be used as a mod wheel, user-configurable but most often used to vary the note’s pitch. The mouse buttons are used to play notes, and can behave slightly differently depending on the mode the instrument is set to.

Not satisfied with simply outputting MIDI notes, [kzra] also designed an intuitive user interface to go along with the mouse. A nice little OLED displays the mode, volume, note, and mouse coordinates, and an 8×8 LED matrix also indicates the note and volume. It’s a fantastic and versatile little instrument, and you’ve gotta check out the video after the break to see it for yourself. We’ve seen some awesome retro-tech MIDI controllers before, and this fits right in.

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Arduino Cable Tracer Helps Diagnose Broken USB Cables

July 18, 2021 by Lewin Day 31 Comments

We’ve all found ourselves swimming amongst too many similar-looking USB cables over the years. Some have all the conductors and functionality, some are weird power-only oddballs, and some charge our phones quickly while others don’t. It’s a huge headache and one that [TechKiwiGadgets] hopes to solve with the Arduino Cable Tracer.

The tracer works with USB-A, Mini-USB, Micro-USB, and USB-C cables to determine whether connections are broken or not and also to identify wiring configurations. It’s built around the Arduino Mega 2560, which is ideal for providing a huge amount of GPIO pins that are perfect for such a purpose. Probing results are displayed upon the 2.8″ TFT LCD display that makes it easy to figure out which cables do what.

It’s a tidy build, and one that we could imagine would be very useful for getting a quick go/no-go status on any cables dug out of a junk box somewhere. Just remember to WIDLARIZE any bad cables you find so they never trouble you again. Video after the break.

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