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.

Via r/duino

It’s great to see people are out there trying to find fun ways to exercise amid the current crisis. Although jumping up and down isn’t great for the knees, it does give decent cardio. But if you don’t have a rope or a puddle, we admit that jumping can lose its bounce pretty fast.

Quarantine has been a game-filled time for [fridaay]. Somewhere between a handful of FPS games, he decided to try to play Google’s offline dinosaur-based side scroller game by making the dinosaur spring over the saguaros whenever he physically jumps in the air. (Video, embedded below.)

Here’s how it works: [fridaay] holds a transmit circuit that consists of an Arduino UNO, an accelerometer module, and an nRF24L01 transceiver, all running on a 9 V battery. Whenever [fridaay] jumps, the accelerometer reads the change in Z and sends it to the receiving circuit, which is just another UNO and nRF. The receiving UNO is connected to a laptop and configured to press the space bar so the dinosaur canters over the cacti.

We’ve never been able to stay alive long enough in the game to see this happen, but apparently you need to crouch at some point in the game. [fridaay] has yet to implement a control for that, but we’re sure he’ll think of something. Jump past the break to see the video, and hit him up if you need the code.

If you have a lot of parts at your disposal, why not make a physical version?

Via r/duino

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?

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.

When one thinks of audio processing, the mind doesn’t usually leap to an 8-bit micro. Despite this, if you’re looking for some glitchy fun, it’s more than possible, as [Amanda Ghassaei] demonstrates with the Arduino Uno in this 2012 throwback project.

The build is designed for vocal effects, based on the idea of granular synthesis. This is where audio samples are chopped up into small chunks, called “grains”, and manipulated in various ways to make fun sounds. Controls on the box allow the nature of the sound created to be modified by the user.

[Amanda]’s project serves as a great example of what it takes to run audio processing on the Arduino Uno. There’s a guide to using the on-board ADC as a microphone input, as well as the construction of a resistor ladder DAC for output. As a neccessity, this also requires discussion of how to write directly to the ATMEGA’s IO ports, rather than using the slower digitalWrite() function typically used in Arduino projects. There’s plenty of value here for anyone learning to do audio on a microcontroller platform.

Overall, it’s a fun project that serves as a good primer for those keen to dive into digital sound processing. Of course, those looking to kick things up a gear would do well to check out the Teensy Audio Library, too. Video after the break.

Phones are pretty great. Used as telephones, they can save us from bad situations and let us communicate while roaming freely, for the most part. Used as computers, they often become time-sucking black holes that can twist our sense of self and reality. Assuming they pick up when you call, phones are arguably a good thing for kids to have, especially since you can hardly find a payphone these days. But how do you teach kids to use them responsibly, so they can still become functioning adults and move out someday? [Jaychouu] believes the answer is inside of a specialized lockbox.

This slick-looking box has a solenoid lock inside that can be unlocked via a keypad, or remotely via the OBLOQ IoT module. [Jaychouu] added a few features that drive it out of Arduino lockbox territory. To prevent latchkey children from cheating the system and putting rocks (or nothing at all) in the box, there’s a digital weight sensor and an ultrasonic sensor that validate the credentials of the contents and compare them with known values.

Want a basic lockbox to keep your phone out of reach while you work? Here’s one with a countdown timer.

LEDs and blinky projects are great, and will likely never fade from our favor. But would you look at this sweeping beauty? This mesmerizing display is made from 36 micro servos with partial Popsicle sticks pasted on the arms. After seeing a huge display with 450 servos at an art museum, [Doug Domke] was inspired to make a scaled-down version.

What [Doug] didn’t scale down is the delightful visuals that simple servo motion can produce. The code produces a three-minute looping show that gets progressively more awesome, and you can stare at that after the break. Behind the pegboard, a single, hardworking Arduino Uno controls three 16-channel PWM controllers that sweep the servos. We like to imagine things other than Popsicle sticks swirling around, like little paper pinwheels, or maybe optical illusion wheels for people with strong stomachs.

You won’t see these in the video, but there are five ultrasonic sensors mounted face-up on the back of the pegboard. [Doug] has optional code built in to allow the servo sticks to follow hand movement. We hope he’ll upload a demo of that feature soon.

Servos can be hypnotic as well as helpful, as we saw in this 114-servo word clock.

Via Arduino blog

Many of us have considered buying an air hockey table, but are put off by the price. And even if the money is there, those things take up a lot of space. How often are you really going to use it?

This DIY air hockey table is the answer. It’s big enough to be fun, but small and light enough to easily stow away in the off-season. At ~$50, it’s a cheap build, provided you have a vacuum cleaner that can switch to blower mode. The strikers, goals, corner guards, and scoreboard enclosure are all 3D-printed, while the pucks and playfield are laser-cut acrylic. [Technovation] glued acrylic feet to the strikers to help them last longer.

The scoreboard is an Arduino Uno plus an LCD that changes color to match the current winner. Scoring must be entered manually with button presses, but we think it would be fairly easy to detect a puck in the goal with a force or weight sensor or something. For now, the RGB LEDs around the edge are controlled separately with a remote. The ultimate goal is to make the Arduino do it. Shoot past the break and cross-check it out.

Already have a table? Had it so long, no one will play you anymore? Build yourself a robotic opponent.