Pulse Visualizer Is A Real Work Of Heart

April 15, 2020 by Kristina Panos 4 Comments

Some projects are all-around simple, such as the lemon battery or the potato clock. Other projects are rooted in simple ideas, but their design and execution elevates them to another level. [Sharathnaik]’s heart visualizer may not be all that electronically complex, but the execution is pulse-pounding.

The closest that most of us will get to seeing our own heartbeat is watching the skin twitch in our neck or wrist. You know that your heart doing the work of keeping you alive, but it’s hard to appreciate how it exerts itself. With just a few components and printed parts, the heart’s pumping action comes to life as your pulse drives single-x scissor mechanisms to push and pull the plastic plates.

This heart visualizer isn’t nearly as complex as the organ it models, and it’s an easy build for anyone just starting out in electronics. Put your finger on the heart rate sensor in the base, and an Arduino Nano actuates a single servo to your own personal beat. We’d love to see it work overtime while someone gets worked up. For now, there’s an even-tempered demo after the break, followed by an assembly video.

Heartbeat sensing can be romantic, too. Here’s a lovely circuit sculpture that runs at the rate of the receiver.

Continue reading “Pulse Visualizer Is A Real Work Of Heart” →

Unique Musical Instrument Defies Description

April 11, 2020 by Dan Maloney 17 Comments

Since the first of our ancestors discovered that banging a stick on a hollow log makes a jolly sound, we hominids have been finding new and unusual ways to make music. We haven’t come close to tapping out the potential for novel instruments, but then again it’s not every day that we come across a unique instrument and a new sound, as is the case with this string-plucking robot harp.

Named “Greg’s Harp” after builder [Frank Piesik]’s friend [Gregor], this three-stringed instrument almost defies classification. It’s sort of like a harp, but different, and sort of like an electric guitar, but not quite. Each steel string has three different ways to be played: what [Frank] calls “KickUps”, which are solenoids that strike the strings; an “eBow” coil stimulator; and a small motor with plastic plectra that pluck the strings. Each creates a unique sound at the fundamental frequency of the string, while servo-controlled hoops around each string serve as a robotic fretboard to change the notes. Sound is picked up by piezo transducers, and everything is controlled by a pair of Nanos and a Teensy, which takes care of MIDI duties.

Check out the video below and see if you find the sound both familiar and completely new. We’ve been featuring unique instruments builds forever, from not-quite-violins to self-playing kalimbas to the Theremincello, but we still find this one enchanting.

Continue reading “Unique Musical Instrument Defies Description” →

LIDAR Built On Familiar Platform

April 11, 2020 by Bryan Cockfield 7 Comments

Moore’s law may have reached its physical limit for transistor density, but plenty of other technologies are still on that familiar path of getting smaller and smaller as time passes. It looks like LIDAR is no exception to this trend either. This project from [Owen] shows a fully-functional LIDAR system for about $20 and built almost entirely on top of an ESP32.

The build uses a Time-Of-Flight IR laser range sensor controlled by the ESP32, and the sensor is much smaller than even the ESP32’s footprint so it takes up very little extra space. To get it to function as a LIDAR system instead of just a simple rangefinder it does need a motor in order to rotate itself to see its entire space. Besides its small form factor and low cost, it also has a handy user interface that can run anywhere an HTML5 browser can run, making the use of the system easy and straightforward as well. All of the code is available on the project’s GitHub page.

We wouldn’t expect a system like this to be driving an autonomous car anytime soon, it’s update rate is far too slow, but its intent for small robots and even as an educational demo for learning LIDAR is second to none. If you do need a little more power in a LIDAR system but still don’t want to break the bank, we featured this impressive setup a few weeks ago.

What Day Is It?

April 8, 2020 by Danie Conradie 15 Comments

With much of the world staying at home at the moment, keeping track of our sanity and the day of the week is a bit of a challenge, especially without the normal daily routine to hold onto. To help with one of these problems, [phreakmonkey] has built a Day Clock. As the name suggests, it’s only purpose is to show what day of the week it is.

Avery simple device, the two main components are a servo and a Wemos D1 Mini, the popular ESP8266-based dev board. Using the NTPtimeESP library, it gets day of the week from the internet, and moves the servo to indicate the current day on a 3D printed face. Most readers should be able to whip one up in an hour or two, which can help keep sane in these interesting times.

For another Corona clock, check out [Elliot Williams]’ version that helps with keeping domestic peace. If you want to do something to combat the spread of the current epidemic, you can build a few face shields, make your idle computer available for Folding@Home or sew a few masks. Every bit helps.

Simon Says, But With Servos

April 7, 2020 by Kristina Panos 12 Comments

How much easier would life be if you could just grab hold of whatever mechanism you wanted to manipulate, move it like you want, and then have it imitate your movements exactly? What if you could give a servo MIDI-like commands that tell it to move to a certain location for a specific duration? Wonder no more, because [peterbiglab] has big-brained the idea into fruition.

With just one wire, an Arduino, and some really neat code, [peter] can get this servo to do whatever he wants. First he tells the Arduino the desired duration in frames per second. Then he grabs the horn and moves it around however he wants — it can even handle different speeds. The servo records and then mimics the movements just as they were made.

The whole operation is way simpler than you might think. As [peterbiglab] demonstrates in the video after the break, the servo knows its position thanks to an internal potentiometer on the motor’s rotor. If you locate the pot output pin on the control board and run a wire from there into an Arduino, you can use that information to calibrate and control the servo’s position pretty easily. There are a ton of possibilities for this kind of control. What would you do with it? Let us know in the comments.

If you want to try this with a bunch of servos at once, might as well build yourself a little testing console.

Continue reading “Simon Says, But With Servos” →

Printed Door Handle Turns Key With A Servo

March 30, 2020 by Tom Nardi 8 Comments

[Madalin Valceleanu] had a somewhat unique problem. He wanted to make his front door a bit “smarter”, but none of the IoT door locks he found were compatible with the style of reinforced door he had. So he set out to design and 3D print his own Internet-controlled door handle.

Now we say handle and not lock because the internal mechanisms haven’t actually been replaced. Those aren’t exactly the kind of parts that lend themselves to being recreated in PLA, after all. The printed components simply replace the original plate and handle on the interior of the door.

In that case, you might be wondering what the point of all this was. If he’s still using the same internal mechanism, how does a new handle help? On his new handle, [Madalin] has integrated a servo that’s capable of turning the original key in the door. With the servo wired up to a Raspberry Pi, this allows him to lock and unlock the door through his home automation system.

[Madalin] has made the STLs for his printed handles available on Thingiverse, but like most of these “bolt on” style door modifications, we imagine the design is bespoke enough that it won’t be much practical use to anyone else. Still, it’s an excellent example of solving a real-world problem with some outside of the box thinking. Continue reading “Printed Door Handle Turns Key With A Servo” →

Self-Playing Whistle While You Work From Home

March 27, 2020 by Kristina Panos 7 Comments

In ridiculous times, it can help to play ridiculous instruments such as the slide whistle to keep your bristles in check. But since spittle is more than a little bit dangerous these days, it pays to come up with alternative ways to play away the days during lockdown life.

Thanks to some clever Arduino-driven automation, [Gurpreet] can maintain a safe distance from his slide whistle while interacting with it. Slide whistles need two things — air coming in from the top, and actuation at the business end. The blowing force now comes from a focused fan like the ones that cool your printed plastic as soon as the hot end extrudes it. A stepper motor moves the slide up and down using a printed rack and pinion.

Here’s a smooth touch — [Gurpreet] added a micro servo to block and unblock the sound hole with a cardboard flap to make the notes more distinct. Check out the build video after the break, which includes a music video for “My Heart Will Go On”, aka the theme from Titanic. It’s almost like the ship herself is playing it on the steam whistles from the great beyond.

Speaking of, did you hear about the effort to raise and restore the remains of her radio room?

Continue reading “Self-Playing Whistle While You Work From Home” →