arduino

2915 Articles

2024 Business Card Challenge: Tiny MIDI Keyboard

June 6, 2024 by 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.

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Using The Moiré Effect For Unique Clock Face

June 3, 2024 by 13 Comments

If you’ve ever seen artifacts on a digital picture of a computer monitor, or noticed an unsettling shifting pattern on a TV displaying someone’s clothes which have stripes, you’ve seen what’s called a Moiré pattern where slight differences in striping of two layers create an emergent pattern. They’re not always minor annoyances though; in fact they can be put to use in all kinds of areas from art to anti-counterfeiting measures. [Moritz] decided to put a few together to build one of the more unique clock displays we’ve seen.

The clock itself is made of four separate Moiré patterns. The first displays the hours with a stretching pattern, the second and third display the minutes with a circular pattern, and the seconds are displayed with a a spiral type. The “hands” for the clock are 3D printed with being driven by separate stepper motors with hall effect sensors for calibration so that the precise orientation of the patterns can be made. A pair of Arduinos control the clock with the high-accuracy DS3231 module keeping track of time, and [Moritz] built a light box to house the electronics and provide diffuse illumination to the display.

Moiré patterns can be used for a number of other interesting use cases we’ve seen throughout the years as well. A while back we saw one that helps ships navigate without active animations or moving parts and on a much smaller scale they can also be used for extremely precise calipers.

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Clock Mixes Analog, Digital, Retrograde Displays

May 30, 2024 by 6 Comments

Unique clocks are a mainstay around here, and while plenty are “human readable” without any instruction, there are a few that take a bit of practice before someone can glean the current time from them. Word clocks are perhaps on the easier side of non-traditional displays but at the other end are binary clocks or even things like QR code clocks. To get the best of both worlds, though, multiple clock faces can be combined into one large display like this clock build from [imitche3].

The clock is actually three clocks in one. The first was inspired by a binary clock originally found in a kit, which has separate binary “digits” for hour, minute, and second and retains the MAX 7219 LED controller driving the display. A standard analog clock rests at the top, and a third clock called a retrograde clock sits at the bottom with three voltmeters that read out the time in steps. Everything is controlled by an Arduino Nano with the reliable DS3231 keeping track of time. The case can be laser-cut or 3D printed and [imitche3] has provided schematics for both options.

As far as clocks builds go, we always appreciate something which can be used to tell the time without needing any legends, codes, or specialized knowledge. Of course, if you want to take a more complex or difficult clock face some of the ones we’re partial to are this QR code clock which needs a piece of hardware to tell the time that probably already has its own clock on it.

A PCB business card with a built-in 4x4 tic-tac-toe game on the back.

2024 Business Card Contest: A Game For Two

May 30, 2024 by 2 Comments

If you want to make a good first impression on someone, it seems like the longer you can keep them talking, the better. After all, if they want to keep talking, that’s a pretty good sign that even if you don’t become business partners, you might end up friends. What better way to make an acquaintance than over a friendly game of tic-tac-toe?

This one will probably take them by surprise, being a 4×4 matrix rather than the usual 3×3, but that just makes it more interesting. The front of the card has all the usual details, and the back is a field of LEDs and micro switches. Instead of using X and O, [Edison Science Corner] is using colors — green for player one, and red for player two. Since playing requires the taking of turns, the microcontroller lights up green and red with alternating single-button presses.

Speaking of, the brains of this operation is an ATMega328P-AU programmed with Arduino. If you’d like to make your own tic-tac-toe business card, the schematic, BOM, and code are all available. Be sure to check out the build and demo video after the break.

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Designing A Quality Camera Slider Can Be Remarkably Satisfying

May 15, 2024 by 7 Comments

Camera sliders are great creative tools, letting you get smooth controlled shots that can class up any production. [Anthony Kouttron] decided to build one for an engineering class, and he ended up mighty satisfied with what he and his team accomplished.

As an engineering class project, this wasn’t a build done on a whim. Instead, [Anthony] and his fellow students spent plenty of time hashing out what they needed this thing to do, and how it should be built. An Arduino was selected as the brains of the operation, as a capable and accessible microcontroller platform. Stepper motors and a toothed belt drive were used to move the slider in a controllable fashion. The slider’s control interface was an HD44780-based character LCD, along with a thumbstick and two pushbuttons. The slider relied on steel tubes for a frame, which was heavy, but cost-effective and easy to fabricate. Much of the parts were salvaged from legendary e-waste bins on the university grounds.

The final product was stout and practical. It may not have been light, but the steel frame and strong stepper motor meant the slider could easily handle even heavy DSLR cameras. That’s something that lighter builds can struggle with.

Ultimately, it was an excellent learning experience for [Anthony] and his team. As a bonus, he got some great timelapses out of it, too. Video after the break.

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Tiny Arduino Drone Even Has An FPV Camera

April 29, 2024 by 15 Comments

In the turmoil of today’s world, drones are getting bigger, badder, and angrier. [Max Imagination] has gone the other way with his work, though, building a teeny Arduino drone that can fit in the palm of your hand. Even if you have a small hand!

The drone is based around an Arduino Pro Mini, and uses an MPU6050 IMU for motion sensing and flight control. Communication with the drone is via an NRF24L01. Four small coreless motors are used for propulsion, driven by tiny MOSFETs, and the whole assembly is run via a teeny 220 mAh lithium-polymer battery. Oh, and there’s an FPV camera so you can put on some goggles and see where it’s going!

Control is via MultiWii software, written specifically for building multirotor craft. [Max] flies the craft using a controller of his own creation, again using an NRF24L01 for communication.

It’s a neat build, and a titchy one too! Tiny drones have a character all their own, even if they can’t really stand up to windier outdoor environments. Video after the break.

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AI System Drops A Dime On Noisy Neighbors

April 25, 2024 by 4 Comments

“There goes the neighborhood” isn’t a phrase to be thrown about lightly, but when they build a police station next door to your house, you know things are about to get noisy. Just how bad it’ll be is perhaps a bit subjective, with pleas for relief likely to fall on deaf ears unless you’ve got firm documentation like that provided by this automated noise detection system.

OK, let’s face it — even with objective proof there’s likely nothing that [Christopher Cooper] is going to do about the new crop of sirens going off in his neighborhood. Emergencies require a speedy response, after all, and sirens are perhaps just the price that we pay to live close to each other. That doesn’t mean there’s no reason to monitor the neighborhood noise, though, so [Christopher] got to work. The system uses an Arduino BLE Sense module to detect neighborhood noises and Edge Impulse to classify the sounds. An ESP32 does most of the heavy lifting, including running the UI on a nice little TFT touchscreen.

When a siren-like sound is detected, the sensor records the event and tries to classify the type of siren — fire, police, or ambulance. You can also manually classify sounds the system fails to understand, and export a summary of events to an SD card. If your neighborhood noise problems tend more to barking dogs or early-morning leaf blowers, no problem — you can easily train different models.

While we can’t say that this will help keep the peace in his neighborhood, we really like the way this one came out. We’ve seen the BLE Sense and Edge Impulse team up before, too, for everything from tuning a bike suspension to calming a nervous dog. Continue reading “AI System Drops A Dime On Noisy Neighbors” →