One-String, One-Trick Pony Plays “the Lick”

October 4, 2023 by Kristina Panos 14 Comments

Wouldn’t you love to be able to play a song on a stringed instrument even though you don’t have an iota of musical talent? That’s the idea behind Strumli, a single-string instrument built by [Factorem] that plays “the lick”. You know, the lick. Chances are, you’ve heard it somewhere before.

Essentially, it’s a pill-shaped bowl with a soundboard. A high-E guitar string is wound around bearings and tuned with a guitar tuner. The lengths of string between the bearings correspond to each note in the lick. Strum it in the right direction, and Bob’s your uncle.

So how the heck did [Factorem] come up with the proper string lengths needed to play the song? After a bit of fancy math involving the equation that represents the relationship between the measurable frequency of a vibrating string under tension and the tension itself, [Factorem] had the overall length of the string. Then it was a matter of finding the frequencies needed to play the lick, along with their corresponding lengths.

Since the string exerts about 80 pounds of tension across the 3D-printed soundboard, some serious internal bracing is required, which [Factorem] figured out in CAD program. All the files are available if you want to build your own. Be sure to check out the build/demo after the break.

Would you rather just build a little harp? Here’s the inspiration for Strumli — a single-string number with a full octave.

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2023 Halloween Hackfest: Flickering Pumpkin Pin Is Solidly Built

October 4, 2023 by Kristina Panos 9 Comments

Now first of all, [Steph] grants that you can already take your pick of several LED pumpkin badges out there on IO. That’s not the point. The point is that this flickering pumpkin pin is nicely-built as well as being open source.

Even though it’s fully featured — it flickers, it’s wearable, and it’s lightweight — the build couldn’t be more simple. It’s fancy through-hole LEDs and a coin cell holder, plus a tack pin to stick it through your shirt. But the final result is quite elegant thanks to clever use of PCB layering.

The first version was to get all the layers right to let the light through and embellish the jack-o-lantern’s lines with manufacturer-applied silver solder, but as [Steph] points out, it looked ‘like something a disturbed child might carve into their desk in detention’. So [Steph] enlisted [Mx. Jack Nelson], who improved the artwork.

Pretty much every component does double duty here, including the tack pin — it serves as a switch because it can hold the battery in place. The battery’s edges reflect the glowing light quite nicely around the edge of the pin. And the LEDs beneath the battery prevent it from slipping out. You can see how it goes together in the video after the break.

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Peggyboard Will Have You Climbing The Walls Repeatedly

October 3, 2023 by Kristina Panos 2 Comments

When you can’t climb actual rocks all the time, what do you do to train and keep sharp? You go to a rock-climbing gym, naturally. But what do you do when it’s 2020 and your rock-climbing gym has shuttered for the foreseeable? You build the best darn rock-climbing wall possible, and you outfit it with an LED for every hold and write an app that lets you plan your route and repeat it later.

This is essentially a DIY version of something called a Moonboard, which, aside from being expensive, was quickly going out of stock back in 2020. [Pegor] started the Peggyboard by building a climbing woody, which is a legendary home climbing wall built by a legendary climber about 20 years ago.

The Peggyboard is Raspberry Pi-powered and has a rather nice app going for it, which [Pegor] has kindly decided to open source.

On the initial screen, the user can select a route and assign the holds as either starting holds, foot holds, hand holds, or finishing holds, each with a different color LED. Another screen lets the user choose a previously-saved route, then apply it to the Peggyboard’s LEDs with the light bulb icon.

Don’t know where to get started building your own climbing wall? You can 3D print climbing holds, you know.

2023 Halloween Hackfest: Treat Trough Of Terror Is Actually Pretty Cute

October 3, 2023 by Kristina Panos 7 Comments

Even though it seems the worst of COVID has passed, October generally kicks off cold and flu season, so why not continue to pass out Halloween treats in a socially-distanced fashion?

That is, of course the idea behind [Gord Payne]’s Halloween Treat Trough of Terror. Lay a treat at the top of the trough and it will activate the LED strips that follow the treat down to the end, as well as some spooky sounds. The treat in question is detected by an SR-04 ultrasonic distance sensor connected to an Arduino Nano.

All in all this was a highly successful build as far as neighborhood entertainment value goes. Toddlers stared in awe at the blinkenlights, teenagers proclaimed it ‘sick’, and we can only assume that the adults were likely happy to see something aimed at kids that’s not scary.

[Gord] has a nice how-to if you want to build your own, and of course, the Arduino sketch is available. Be sure to check it out in action after the break.

Don’t have room to build a treat slide? Here’s a socially-distanced dispenser that lets them stomp a giant button.

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2023 Halloween Hackfest: Ouija Robot Is Even Creepier Than The Real Thing

October 2, 2023 by Kristina Panos 8 Comments

When you’re a kid, nothing says spooky like turning off the lights and bringing out the Ouija board. For decades, this mystifying oracle has purported to channel the dead by spelling out messages using a board with numbers, letters, yes/no, and a heart-shaped windowed bit of plastic called a planchette.

While the action of a standard Ouija board owes itself to something called the ideomotor phenomenon, this motorized Ouija robot by [Ronald McCollum] is powered by tweets.

That’s right, the mannequin hand uses the planchette to spell out the tweets with a rather crisp snap of the wrist. [Ronald] impressively coded all the positions by hand, with each letter being comprised of both a hand position and planchette position.

This project utilizes both an Adafruit Crickit board and a Raspberry Pi, mostly because [Ronald] wanted to use the Crickit for something, and added the Pi to spell out the tweets on the display in real time. Check it out in action after the break, and stick around for a bonus video of the numbers being laser-cut.

Speaking of creepy motion, here’s a refrigerator clock that uses those colorful alphanumeric magnets.

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You’ve Got Mail: Faster And Faster We Go

September 27, 2023 by Kristina Panos 9 Comments

When we last left the post office, they had implemented OCR to read even the sloppiest of handwriting. And to augment today’s 99% accuracy rate, there’s a center full of humans who can decipher the rest of those messy addresses with speed and aplomb. Before that, we took a look at many of the machines that make up the automated side of the post office’s movements. But what was being done to improve the customer experience during all of this time?

Quite a bit, as it turns out. In this installment, we’ll take a look at the development of vending machines and programs like Speed Mail, Missile Mail, and V-Mail (no, not voicemail!) as they relate to enhanced customer service over the years.

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Dead E. Ruxpin Appears Alive And Well

September 26, 2023 by Kristina Panos 12 Comments

What are you doing to scare trick-or-treaters this Halloween? Surely something, right? Well, Hackaday alum [CameronCoward] certainly has his holiday under control with Dead E. Ruxpin, a murderous, cassette tape-controlled animatronic bear.

Readers of a certain vintage will no doubt see the correlation to Teddy Ruxpin, an animatronic bear from the 1980s whose mouth moved as it read stories from cassette tapes. Cleverly, the engineers used one stereo channel for the story’s audio, and the other channel to control the bear’s mouth.

Dead E. Ruxpin takes this idea and expands it, using the same two channels to send audio and control three servo motors that move both arms and the mouth. How is this possible? By sending tones built from one or more frequencies.

Essentially, [Cameron] assigned a frequency to each movement: mouth open/closed, and left and/or right arm up or down. These are all, of course, synced up with specific points in the audio so Dead E. doesn’t just move randomly, he dances along with the music.

The bear is actually a hand puppet, which leaves room for a 3D-printed skeleton that holds the RP2040 and the servos and of course, moves the puppet’s parts. We can’t decide if we prefer the bulging bloodshot eyes, or think the cutesy original eyes would have made a scarier bear. Anyway, check out the build/demo video after the break to see it in action.

Are you now into Teddy Ruxpin? Here’s a bit more about those scare bears. And don’t forget, Halloween Hackfest runs now until October 31st.

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