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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?

We once saw a Romeo and Juliet production where the two families were modern-day mob families with 3-piece suits and pistols. If they made King Richard III set in this week, the famous line might be: “Hand sanitizer, hand sanitizer, my kingdom for hand sanitizer!” Even if you have a supply stashed in your prepper cache, you have to touch the bottle so you could cross-contaminate with other users. Public places often have automatic dispensers to combat this, and now you can too. [Just Barran] shows the device in a video, you can see below.

Sourcing parts for projects is sometimes a problem, but right now we are betting the hand sanitizer will be the hardest component. Of course, the Internet is ripe with homemade brews that may or may not be effective based on beer, grain alcohol, or a variety of other base materials.

[Barran] has a big junk box. so he snagged an Arduino and an ultrasonic sensor. The part that is a little tricky is pulling down the pump. The basic idea is to use a servo motor to pull some fishing line. To engage the bottle, there is a small bit of plastic from a notebook cover and the fishing line goes to both sides of it. One side of the fishing line is fixed and the other is what the servo pulls.

We might have used a solenoid to push the button, but we like the servo method for its simplicity. In the end, it does look like it works well. Changing the bottle out probably requires a little surgery since there is a screw holding the plastic bracket in and you might have to update the fishing line lengths. That might be an impediment for a commercial project, but for your own use, it doesn’t seem like it would be a problem.

Fishing line is more useful than you might think. We’ve even seen it used as belts in 3D printers.

Want to take that annoyingly productive coworker down a notch? Yeah, us too. How dare they get so much done and be so happy about it? How is it possible that they can bang on that keyboard all day when you struggle to string together an email?

The Slippy Slapper is a useless machine that turns people into useless machines using tactics like endless distraction and mild physical violence. It presses your buttons by asking them to press buttons for no reason other than killing their productivity. When they try to walk away, guess what? That’s another slappin’. Slippy Slapper would enrage us by proxy if he weren’t so dang cute.

You’re right, you don’t need an Arduino for this. For peak inefficiency and power consumption, you actually need four of them. One acts as the master, and bases its commands to the other three on the feedback it gets from Slippy’s ultrasonic nostrils. The other three control the slappin’ servos, the speakers, and reading WAV files off of the SD card. Slap your way past the break to see Slippy Slapper’s slapstick demo.

Need to annoy a group of coworkers all at once? Slip a big bank of useless machines into the conference room while it’s being set up.

Would you like to know the great thing about this community we have here? All the spitballing that goes on every day in the comments, the IO chat rooms, and in the discussion threads of thousands of projects. One of our favorite things about the Hackaday universe is that we help each other out, and because of that, our collective curiosity pushes so many designs forward.

[Gurpreet] knows what we’re talking about. He’s back with version two of his self-playing kalimba, driven as strongly as ever by the dulcet tones of the Avatar theme. Now the robo-kalimba is rocking two full octaves, and thanks to your comments and suggestions, has relocated the servos where they can’t be picked up by the soundboard.

We gasped when we saw the new mechanism — a total of 15 rack and pinion linear actuators that make the kalimba look like a tiny mechanical pipe organ. Now the servos float, fixed into a three-part frame that straddles the sound box. [Gurpreet] melted servo horns to down to their hubs rather than trying to print something that fits the servos’ sockets.

Thumb your way past the break to check out the build video. [Gurpreet] doesn’t shy away from showing what went wrong and how he fixed it, or from sharing the 3D printering sanity checks along the way that kept him going.

Plucking kalimba tines is a difficult problem to solve because they’re stiff, but with timbre sensitive to many degrees of pressure. A slightly easier alternative? Make a toy player piano.

Flip displays are an interesting piece of technology, physically moving segments into place that stay put until other information is needed. Michael Klements has been especially fascinated by these devices, and after inspiration from another project, he decided to craft his own.

His version utilizes 14 micro servos to flip segments into a visible position, then rotate them to 90° when no longer needed. This “off” mode displays a slimmer profile, and the sides and back are painted black, making them much less visible.

An Arduino Mega, with 15 possible PWM outputs, is used to control the servos, while a hobby RC-style battery eliminator circuit provides power to the motors. 

Be sure to check out the build process and in-action shots below! 

It’s that time of year again when production in Shenzhen grinds to a halt. Lunar New Year has kicked off the annual month-long Spring Festival, and the whole country has taken time off to be with family and celebrate. One tradition of Spring Festival is that everyone gives each other red envelopes with various amounts of money in them called hongbao. The point of this ‘lucky money’ is to spread good fortune in the new year, and it’s easy to amass a whole pile of hongbao by the end of the festival.

[Makerming] made this lovely counting box for anyone looking to keep track of their hongbao in style. It probably goes without saying that this would make an awesome mailbox for Valentines (or anything else that fits in the slot), but there you go. The circuit is pretty simple thanks to a Grove connector shield meant for Arduinos. An IR break-beam module detects the incoming envelope, and the Uno increments the count on the display. The wiggly, servo-driven example hongbao on top are there to add to the fun.

We love the laser-cut decoration on the front, which is an homage to the intricate paper cut decorations. If you don’t like that one, [Makerming] included design files for several other options. Watch it wiggle after the break!

If you won’t be looking to collect valentines because you’ve already found that special someone, give them something that lasts longer than chocolate or roses.

Via Adafruit

When you’re a kid, remote control cars are totally awesome. Even if you can’t go anywhere by yourself, it’s much easier to imagine a nice getaway from the daily grind of elementary school if you have some wheels. And yeah, R/C cars are still awesome once you’re an adult, but actual car-driving experience will probably make you yearn for more realism.

What could be more realistic and fun than an active suspension? Plenty of adults will never get the chance to hit the switches in real car, but after a year of hard work, [snoopybg] is ready to go front and back, side to side, and even drift in this super scale ’63 Oldsmobile Dynamic 88 wagon. We think you’ll agree that [snoopybg] didn’t miss a detail — this thing makes engine noises, and there are LEDs in the dual exhaust pipes to simulate flames.

An Arduino reads data from a triple-axis accelerometer in real time, and adjusts a servo on each wheel accordingly, also in real time, to mimic a real car throwing its weight around on a real suspension system. If that weren’t cool enough, most of the car is printed, including the tires. [snoopybg] started with a drift car chassis, but even that has been hacked and drilled out as needed.

There are a ton of nice pictures on [snoopybg]’s site if you want to see what’s under the hood. We don’t see the code anywhere, but [snoopybg] seems quite open to publishing more details if there is interest out there. Strap yourself in and hold on tight, because we’re gonna take this baby for a spin after the break.

If this is all seems a bit much for you, but you’ve got that R/C itch again, there’s a lot to be said for upgrading the electronics in a stock R/C car.

Via r/duino

You know how it goes — sometimes you just have to stop in the middle of a project and build yourself a tool that vastly improves your workflow as soon as it’s completed. [Ikkalebob] aka [Will Cogley] on YouTube is working on some super secret project that requires a whole bunch of servos. And since all of them have to be tested and set, he built this adorable servo tester as a time-saving gift to himself.

This tester revolves around an Adafruit 16-channel servo driver and an Arduino Uno. The servos show up on the screen in groups of four, and can be tested four at a time with the pots. The buttons let [Ikkalebob] move up and down between the groups. The SainSmart LCD proved to be more difficult to set up than others, but [Ikkalebob] did you a solid and tweaked the library. It’s available along with his code and STLs.

Speaking of STLs, we really dig the mini NASA console look and the folding enclosure. Leveraging the print process to build hinges and other things is awesome, and so is getting away with using fewer fasteners. You can see a bit of how [Ikkalebob] designed it in the video after the break.

Depending on what you’re doing with servos, you might want a different kind of testing suite. Here’s one that’s geared toward RC pilots.

[Will] wanted to build some animatronic eyes that didn’t require high-precision 3D printing. He wound up with a forgiving design that uses an Arduino and six servo motors. You can see the video of the eyes moving around in the video below.

The bill of materials is pretty simple and features an Arduino, a driver board, and a joystick. The 3D printing parts are easy to print with no supports, and will work with PLA. Other than opening up holes there wasn’t much post-processing required, though he did sand the actual eyeballs which sounds painful.

The result is a nice tight package to hold six motors, and the response time of the eye motion is very impressive. This would be great as part of a prop or even a robot in place of the conventional googly eyes.

While the joystick is nice, we’d like to see an ultrasonic sensor connected so the eyes track you as you walk across the room. Maybe they could be mounted behind an old portrait for next Halloween. Then again, perhaps a skull would be even better. If you want a refresher about servos, start with a laser turret tutorial.

Servos aren’t particularly hard to control with Arduinos, and in fact there’s a library available just for that purpose. Actually making the connection between the board and servo and managing one’s power usage will require a bit more finesse.

In the video below, Jeremy S. Cook explains how you can create an adapter that goes between your servo and an Uno, including a capacitor to help even out voltage spikes. While in most cases you would want to supply power your servos separately from the Arduino, this technique seems to work well in a quick round of tests. 

In addition, the clip shows how to attach a servo and then detach it to cut it off, using a function outside of the main loop and no additional hardware. This would be very helpful in applications where power is at a premium — or if you just don’t want the servo jittering back and forth!



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