arduino

2859 Articles

Mini Meters Monitor Microprocessor Maximization

December 4, 2023 by 11 Comments

[Lex] over at Computing: The Details loves to make fun projects. Recently, they have created a hardware CPU monitor that displays how PCs are parallelizing compile tasks at a glance. The monitor is built from 14 analog meters, along with some WS2812 RGB LEDs.

Each meter represents a core on [Lex]’s CPU, while the final two meters show memory and swap usage. The meters themselves are low-cost 5 mA devices. Of course, the original milliamps legends wouldn’t do much good, so [Lex] designed and printed graduations that glue over the top. The RGB LED strip is positioned so two LEDs fit under each meter. The LEDs allow a splash of color to draw attention to the current state of the machine. The whole bank going red would sure get our attention!

The system is controlled by an Arduino Mega, with the meters driven using the PWM pins. The only extra part is a 1 kΩ resistor. The Arduino wrangles the LEDs as well. Sadly [Lex] did not include the software. They did describe it though. Basically they are using a Rust program to call systemstat, obtaining the current CPU utilization data in Linux. A bit of math converts this into pointer values and LED colors. The data is then sent via USB-serial to the Arduino Mega. The software savvy will say it’s pretty easy to replicate, but the hardware-only hackers among us might need a bit of help.

This isn’t the first custom meter we’ve seen on Hackaday. Your author’s first project covered by Hackaday was for a meter created using an automotive gauge stepper motor. I didn’t include source code either – but only because [Guy Carpenter]’s Switec X25 library had me covered.

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LED Tester Also Calculates Resistor For Target Voltage

December 2, 2023 by 12 Comments

[mircemk] built a slick-looking LED tester with a couple handy functions built in. Not only can one select a target current to put through an LED, but by providing a target voltage, the system will automatically calculate the necessary series resistor. If for example the LED is destined for 14 V, this device will not only show how the LED looks at the chosen current, but will calculate the required resistor to get the same results on a 14 V system.

The buttons on the left control the target current and the voltage of the destination system. Once an LED is connected it will light up and the display indicates the LED’s forward voltage, the LED current, and the calculated series resistor value to obtain the same result at the selected target voltage. It’s a handy way to empirically dial in LED brightness values without needing to actually set up any particular test environment.

On the inside there’s little more than a handful of passive components, an Arduino, an LCD display, and a few buttons. This kind of tool reminds us of the highly clever component testers that hit the hobbyist scene years ago, showing what kind of advanced tricks a modern microcontroller is capable of with the right programming. (Here’s a look at how those work, if you’re interested in some deeper details.)

[mircemk] demonstrates his tool in the video, embedded below. We particularly like the attention he paid to the enclosure, giving it a very functional layout. It goes to show that when designing something, it’s never too early to consider enclosure and UI layout.

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Robot Pianist Runs On Arduino Nano

December 1, 2023 by 7 Comments

The piano has been around for a long time now. Not long after its invention, humans started contemplating how they could avoid playing it by getting a machine to do the job instead. [vicenzobit] is the latest to take on this task, building a “Robot Pianista” that uses a simple mechanism to play a tune under electronic command (Spanish language, Google Translate link).

An Arduino Nano is the heart of the build, paired with a shield that lets it run a number of servo motors. The servos, one per key, are each assembled into a 3D-printed bracket with a cam-driven rod assembly. When the servo turns, the cam turns, and pushes down a rod that presses the piano key.

The build is limited in the sense that you can only play as many keys as you have servo channels, but nonetheless, it does the job. With eight servos, it’s able to play a decent rendition of Ode to Joy at a steady tempo, and that’s an excellent start.

We’ve featured some great mechanized instruments before, too. Video after the break.

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Watch Time Roll By On This Strange, Spiral Clock

November 13, 2023 by 15 Comments

[Build Some Stuff] created an unusual spiral clock that’s almost entirely made from laser-cut wood, even the curved and bendy parts.

The living hinge is one thing, but getting the spacing, gearing, and numbers right also takes work.

The clock works by using a stepper motor and gear to rotate the clock’s face, which consists of a large dial with a spiral structure. Upon this spiral ramp rolls a ball, whose position relative to the printed numbers indicates the time. Each number is an hour, so if the ball is halfway between six and seven, it’s 6:30. At the center of the spiral is a hole, which drops the ball back down to the twelve at the beginning of the spiral so the cycle can repeat.

The video (embedded below) demonstrates the design elements and construction of the clock in greater detail, and of particular interest is how the curved wall of the spiral structure consists of a big living hinge, a way to allow mostly rigid materials to flex far beyond what they are used to. Laser cutting is well-suited to creating living hinges, but it’s a technique applicable to 3D printing, as well.

Thanks to [Kelton] for the tip!

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Arduino Sticker Dispenser Saves Time

November 12, 2023 by 18 Comments

What’s the worst part about packaging up a whole lot of the same basic thing? It might just be applying the various warning stickers to the outside of the shipping box. Luckily, [Mr Innovative] has built an open-source automatic sticker dispenser that does the peeling for you, while advancing the roll one at a time quite satisfyingly.

This tidy build is made primarily of 20×20 extruded aluminium and stainless steel smooth rod. All the yellow bits are 3D printed. The brains of this operation is an Arduino Nano, with an A4988 stepper motor driver controlling a NEMA17.

Our favorite part of this build is the IR sensor pair arranged below the ready sticker. It detects when a sticker is removed, then the stepper advances the roll by one sticker height. The waste is collected on a spool underneath.

Between the video and the instructions, [Mr Innovative] has made it quite simple to build one for yourself. Definitely check this one out after the break.

[Mr Innovative] may as well go by [Mr. Automation]. Check out this automated wire prep machine from a few years ago.

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An Open-Source Ebike Motor Controller

November 8, 2023 by 18 Comments

DIY e-bikes are often easy to spot. If they’re not built out of something insane like an old washing machine motor, the more subtle kits that are generally used still stand out when compared to a non-assisted bike. The motors tend to be hub- or mid-drive systems with visible wires leading to a bulky battery, all of which stand out when you know what to look for. To get a stealthy ebike that looks basically the same as a standard bicycle is only possible with proprietary name-brand solutions that don’t lend themselves to owner repair or modification, but this one has at least been adapted for use with an open source motor controller.

The bike in use here is a model called the Curt from Estonian ebike builder Ampler, which is notable in that it looks indistinguishable from a regular bicycle with the exception of the small 36-volt, 350-watt hub motor somewhat hidden in the rear wheel. [BB8] decided based on no reason in particular to replace the proprietary motor controller with one based on VESC, an open-source electric motor controller for all kinds of motors even beyond ebikes. Installed on a tiny Arduino, it fits inside the bike’s downtube to keep the stealthy look and can get the bike comfortably up to around 35 kph. It’s also been programmed to turn on the bike’s lights if the pedals are spun backwards, and this method is also used to change the pedal assist level, meaning less buttons and other user-interface devices on the handlebars. Continue reading “An Open-Source Ebike Motor Controller” →

Servo Claw Game Puts Your Muscles To The Test

November 5, 2023 by 5 Comments

As fun as claw games are, the jaws are always disappointingly weak, and you usually end up with bupkis. What if the jaws were completely within your  control? That’s the idea behind [Upside Down Labs]’ muscle-controlled servo claw game.

While electromyography (EMG) is great for identifying neuro-muscular abnormalities and allows for amazing prosthetic limbs to work, it can also be used for fun. As you’ll see in the video after the break, accurate block-stacking (and possible candy-grabbing) depends on teamwork and tensed muscles.

Though the user provides the muscle, the brains behind this operation is an Arduino Uno with a Muscle BioAmp shield stacked on top, which [Upside Down Labs] also created. This shield makes it ridiculously easy to connect EMG sensors and other I²C devices like screens and, well, servo claws. From there, it’s really just a matter of printing the claw, connecting it to a 9g servo, and using an accompanying kit to prepare the skin and connect the muscles to the Arduino. Be sure to check it out in tense block-stacking action after the break.

If you want to listen in on your muscles, look no further than the BioAmp EMG Pill.

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