Battery-Powered Watering Timer Converted To Solar On The Cheap

May 12, 2018 by Dan Maloney 13 Comments

Watering the garden or the lawn is one of those springtime chores that is way more appealing early in the season than later. As the growing season grinds along, a chore that seemed life-giving and satisfying becomes, well, just another chore, and plants often suffer for it.

Automating the watering task can be as simple as buying a little electronic timer valve that turns on the flow at the appointed times. [A1ronzo] converted his water hose timer to solar power. Most such timers are very similar, with a solenoid-operated pilot valve in line with the water supply and an electronic timer of some sort. The whole thing is quite capable of running on a pair of AA batteries, but rather than wasting money on new batteries several times a season, he slipped a LiPo pack and a charge controller into the battery case slot and connected a small solar panel to the top of the controller.

The LiPo is a nominal 3.7-volt pack, so he did a little testing to make sure the timer would be OK with the higher voltage. The solar panel sits on top of the case, and the whole thing should last for years. And bonus points for never having to replace a timer that you put away at the end of the season with batteries still in it, only to have them leak. Ask us how we know.

Like the best of hacks, this one is quick, easy and cheap — $15 in parts, aside from the timer. There are more complicated irrigation solutions, of course, one of which even won the Hackaday Prize once upon a time. But this one has us ordering parts to build our own right now.

Modified Uke Keeps The Beat With A Solenoid

December 2, 2017 by Kristina Panos 13 Comments

A classic one-man band generally features a stringed instrument or two, a harmonica in a hands-free holder, and some kind of percussion, usually a bass drum worn like a backpack and maybe some cymbals between the knees. The musician might also knock or tap the sound-boards of stringed instruments percussively with their strumming hand, which is something classical and flamenco guitarists can pull off with surprising range.

The musician usually has to manipulate each instrument manually. When it comes to percussion, [JimRD] has another idea: keep the beat by pounding the soundboard with a solenoid. He built a simple Arduino-driven MOSFET circuit to deliver knocks of variable BPM to the sound-board of a ukulele. A 10kΩ pot controls the meter and beat frequency, and the sound is picked up by a mic on the bridge. So far, it does 3/4 and 4/4 time, but [JimRD] has made the code freely available for expansion. Somebody make it do 5/4, because we’d love to hear [JimRD] play “Take Five“.

He didn’t do this to his good uke, mind you—it’s an old beater that he didn’t mind drilling and gluing. We were a bit skeptical at first, but the resonance sweetens the electromechanical knock of the solenoid slug. That, and [JimRD] has some pretty good chops. Ax your way past the break to give it a listen.

Got a cheap ukulele but don’t know how to play it? If you make flames shoot out from the headstock, that won’t matter as much. No ukes? Just print one.

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Wind Chimes And Dry Ice Make An Unusual Musical Instrument

September 19, 2017 by Dan Maloney 29 Comments

When it comes to making music, there are really only a few ways to create the tones needed — pluck something, blow into something, or hit something. But where does that leave this dry-ice powered organ that recreates tunes with wind chimes and blocks of solid CO2?

It turns out this is firmly in the “hit something” camp, as [Leah Edwards] explains of her project. When the metal wind chime tubes come in contact with dry ice, the temperature difference sublimates the solid CO2. The puff of gas lifts the tube slightly, letting it fall back against the brick of dry ice and making a tone. The process is repeated rapidly, providing a vibrato effect while the tube is down. [Leah] used solenoids to lift the tubes and, having recently completed a stint at National Instruments, a bunch of NI gear to control them. The videos below show a few popular tunes and a little bit about the organ build. But what — no songs from Frozen?

We can easily imagine this same build using an Arduino or some other microcontroller. In fact, it puts us in mind of a recent reed organ MIDI project that has a few ideas to offer, like ways to quiet those solenoids. Continue reading “Wind Chimes And Dry Ice Make An Unusual Musical Instrument” →

Music Box Plays “Still Alive” Thanks To Automated Hole Puncher

September 19, 2017 by Donald Papp 20 Comments

Most projects have one or two significant aspects in which custom work or clever execution is showcased, but this Music Box Hole Punching Machine by [Josh Sheldon] and his roommate [Matt] is a delight on many levels. Not only was custom hardware made to automate punching holes in long spools of paper for feeding through a music box, but a software front end to process MIDI files means that in a way, this project is really a MIDI-to-hand-cranked-music-box converter. What a time to be alive.

The hole punch is an entirely custom-made assembly, and as [Josh] observes, making a reliable hole punch turns out to be extremely challenging. Plenty of trial and error was involved, and the project’s documentation as well as an overview video go into plenty of detail. Don’t miss the music box version of “Still Alive”, either. Both are embedded below.

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Reed Organ MIDI Conversion Tickles All 88 Keys

September 13, 2017 by Dan Maloney 11 Comments

What did you do in high school? Chances are it wasn’t anywhere near as cool as turning a reed organ into a MIDI device. And even if you managed to pull something like that off, did you do it by mechanically controlling all 88 keys? Didn’t think so.

A reed organ is a keyboard instrument that channels moving air over sets of tuned brass reeds to produce notes. Most are fairly complex affairs with multiple keyboards and extra controls, but the one that [Willem Hillier] scored for free looks almost the same as a piano. Even with the free instrument [Willem] is about $500 into this project. Almost half of the budget went to the solenoids and driver MOSFETs — there’s a solenoid for each key, after all. And each one required minor surgery to reduce the clicking and clacking sounds that don’t exactly contribute to the musical experience. [Willem] designed custom driver boards for the MOSFETs with 16 channels per board, and added in a couple of power supplies to feed all those hungry solenoids and the three Arduinos needed to run the show. The video below shows the organ being stress-tested with the peppy “Flight of the Bumblebee”; there’s nothing wrong with a little showing off.

[Willem]’s build adds yet another instrument to the MIDI fold. We’ve covered plenty before, from accordions to harmonicas and even a really annoying siren.

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Early Electromechanical Circuits

February 1, 2017 by Steven Dufresne 25 Comments

In the days before semiconductor diodes, transistors, or even vacuum tubes, mechanical means were used for doing many of the same things. But there’s still plenty of fun to be had in using those mechanical means today, as [Manuel] did recently with his relay computer. This post is a walk through some circuits that used those mechanical solutions before the invention of the more electronic and less mechanical means came along.

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Robo-Flute Whistles MIDI

January 23, 2017 by Al Williams 6 Comments

We aren’t sure this technically qualifies as music synthesis, but what else do you call a computer playing music? In this case, the computer is a Teensy, and the music comes from a common classroom instrument: a plastic recorder. The mistaken “flute” label comes from the original project. The contraption uses solenoids to operate 3D printed “fingers” and an air pump — this is much easier with a recorder since (unlike a flute) it just needs reasonable air pressure to generate sound.

A Teensy 3.2 programmed using the Teensyduino IDE drives the solenoids. The board reads MIDI command sent over USB from a PC and translates them into the commands for this excellent driver board. It connects TIP31C transistors, along with flyback diodes, to the solenoids via a terminal strip.

On the PC, a program called Ableton sends the MIDI messages to the Teensy. MIDI message have three parts: one sets the message type and channel, another sets the velocity, and one sets the pitch. The code here only looks at the pitch.

This is one of those projects that would be a lot harder without a 3D printer. There are other ways to actuate the finger holes, but being able to make an exact-fitting bracket is very useful. Alas, we couldn’t find a video demo. If you know of one, please drop the link in the comments below.

We have seen bagpipe robots (in fact, we’ve seen several). We’ve also seen hammering shotguns into flutes, which is certainly more melodious than plowshares.