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.
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.
It’s really quite unfortunate that Hackaday/Supplyframe employees and their families are not allowed to place in the 2023 Halloween Hackfest, because our own [Tom Nardi] has thrown down a costume gauntlet with his kids’ proton pack conversion.
Starting with an inert off-the-shelf toy from 2021, [Tom] set out to make the thing more awesome in every way possible. For one thing, it’s blue, and outside of the short-lived animated series The Real Ghostbusters, who ever heard of a blue proton pack? So one major change was to paint it matte black and age it with the old silver rub ‘n buff technique. And of course, add all the necessary stickers.
[Tom] added plenty of blinkenlights, all running off of an Arduino Nano clone and a pair of 18650s. He got lucky with the whole power cell thing, because an 8 x 5050 RGB LED stick fits there perfectly and looks great behind a PETG diffusing lens. He also drilled out and lit up the cyclotron, because what’s a proton pack without that? There’s even a 7-segment LED voltmeter so Dad can check the power level throughout the night.
Finally, he had to do a bit of engineering to make the thing actually wearable by his daughter. A frame made of square aluminium tubing adds strength, and a new pair of padded straps make it comfortable. Be sure to check it out in action after the break.
Sometimes, projects start in somewhat unlikely places. This one began when [Istvan Raduly] scored a fake raven at a neighbor’s garage sale and decided to turn it into a thunder-and-lightning decoration that would frighten even the bravest trick-or-treater.
Get close enough to this raven and you’ll set off the PIR sensor, which triggers lighting and sound effects, including some spooky glowing and blinking red eyes, general cawing, and of course, thunder. The light comes from a whopping 10-watt, 12-volt power LED. This bird’s brain is an Arduino Nano, which is protected from the 12V supply with a boost converter. As you might expect, the sounds are on an SD card and played through a DF Player Mini.
Spookiness aside, our favorite part might be the absolutely lovely job that [Istvan] did decorating the raven’s base. Hiding electronics and hot glue is one thing, but this is above and beyond. Be sure to check it out after the break, both in the safety of the house, and outside in the scary darkness.
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.
Although many people might remember the recorder as just a simple instrument from their introductory music classes, it can nevertheless produce rich and varied melodies in the hands of a virtuoso like Frans Brüggen. [Luis Marx] also took music lessons as a child, but never progressed much beyond an elementary level. Instead, he preferred to spend his time honing his engineering skills, which eventually enabled him to get back into music.
Initially, he wanted to build a piano-playing exoskeleton, to marionette his fingers up and down the ivories, but had to bail on that one because of the insane complexity. So instead, he built himself a robot that helps him play the recorder. (Video, in German, embedded below, fast-forwarded to the recorder part.)
A recorder has eight finger holes, which can be covered or uncovered in various combinations to produce tones. [Luis] therefore used eight solenoids, mounted on a 3D-printed frame, to actuate the finger holes. The basic idea worked, but getting the solenoids to fully cover the holes each time turned out to be a challenge: even a slight misalignment would cause air to leak past the plug and produce a horrible off-key sound.
After a lot of trial and error, [Luis] found foam earplugs to be a pretty good material for emulating human fingertips. He also discovered that relying on the solenoids’ spring tension to keep the holes closed was not reliable; a better solution was to flip the solenoids around and use the much larger force from their powered stroke to create an air-tight seal.
The solenoids are driven by an Arduino Nano through a set of MOSFET modules, powered by a lithium battery. [Luis] wrote some Arduino sketches with famous melodies like Beethoven’s Für Elise, which sound quite decent on the robo-recorder: perhaps not on Frans Brüggen’s level, but pretty impressive for a self-declared “music noob” like [Luis].
Many robotic musicians play instruments like pianos or xylophones. Instruments from the flute family are harder to automate, but it has been donebefore. We’ve even seen a MIDI-powered harmonica.
[Koraks tinkers] was gifted a gargantuan photographic enlarger, a Durst Laborator 138 s, which is a unit designed specifically for black and white usage only. This was not good enough for [Koraks] so down the rabbit hole of conversion to colour we go! The moral of the story is this: if you can’t find it, build it. The hacker mentality. After wasting time and effort trying to source a period colour head for the thing, [Koraks] did the decent thing and converted what was already in front of them.
A hacked Chinese-sourced COB array. This is no use.
Now, if you’re thinking this process is simply a matter of ripping out the tungsten bulb and sticking a high-power RGB array in there, then you’re going to be disappointed! You see, colour photography of the era — specifically the RA4 process in this case — requires careful colour calibration and is heavily biased towards the red end of the visible spectrum, due to the colour curve of those tungsten bulbs we touched upon earlier.
Attempt 2: With a heavy bias towards the red end of the spectrum
The first attempt at using an off-the-shelf COB array was a bust — it simply wasn’t bright enough once the light had passed through the diffuser plate, and the light path losses were too high to expose the RA4 paper sufficiently, especially at the red end of the spectrum. Quite simply this is due to the reduced energy of red photons (compared to blue) making the desired chemical reaction rate too low. The solution is more power.
Another issue that quickly raised itself was that 8-bits of PWM control of the RGB components was inadequate since the ratio of blue to red required was so skewed, that only a few effective bits of blue channel control were usable, and that was far too granular to get the necessary accuracy.
[Koraks’] approach was to custom build an LED array with twenty red 3W LEDs and eight each of the green and blue devices. 12-bits of PWM resolution was delivered via a PCA9685 PWM controller, that also handily controlled the cooling fans. The whole thing was hooked up to an Arduino Nano, with an MCP23016 expander board performing the duty of interfacing the rotary encoders and trigger footswitch. In fact, several iterations of the LED array have been constructed and this four-part blog series (Part1, Part2, Part3, Part4) lays out the whole story in all its gory detail for your entertainment. Enjoy!
