UnifiedWater Finds Potable Water And Stops Polluters

Millions of people all over the world don’t have access to clean drinking water, and it’s largely because of pollution by corporations and individuals. Solving this problem requires an affordable, scalable way to quickly judge water quality, package the data, and present it to an authority that can crack down on the polluters before the evidence dissipates. Ideally, the solution would be open source and easy to replicate. The more citizen scientists, the better.

[Andrei Florian]’s UnifiedWater flows directly from this line of thinking. Dip this small handheld device below the surface, and it quickly takes a bunch of water quality and atmospheric readings, averages them, and sends the data to a web dashboard using an Arduino MKR GSM.

UnifiedWater judges quality by testing the pH and the turbidity of the water, which gauges the amount of impurities. Commercial turbidity sensors work by measuring the amount of light scattered by the solids present in a liquid, so [Andrei] made a DIY version with an LED pointed at a photocell. UnifiedWater also reads the air temperature and humidity, and reports its location along with a timestamp.

This device can run in one of two modes, depending on the application. The enterprise mode is designed for a fleet of devices placed strategically about a body of water. In this mode, the devices sample continuously, taking readings every 15 minutes, and can send notifications that trigger on predefined thresholds. There’s also a one-and-done individual mode for hikers and campers who need to find potable water. Once UnifiedWater takes the readings, the NeoPixel ring provides instant color-coded judgment. Check out the demo after the break.

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Synthfonio Makes Music Easy Like Sunday Morning

This one goes out to anyone who loves music and feels it in their soul, but doesn’t necessarily understand it in their head. No instrument should stand in the way of expression, but it seems like they all do (except for maybe the kazoo).

[FrancoMolina]’s hybrid synth-MIDI controller is a shortcut between the desire to play music and actually doing it. Essentially, you press one of the buttons along Synthfonio’s neck to set the scale, and play the actual notes by pressing limit switches in the controller mounted on the body. If you’re feeling blue, you can shift to minor scales by pressing the relative minor note’s neck button at the same time as the root note, e.g. A+C=Am. Want to change octaves? Just slide the entire controller up or down for a total of three.

All of these switches are muxed to two Arduinos — an MKR1010 for USB MIDI control, and a bare ‘328 to provide the baked-in synth sounds. Power comes from a stepped-up 18650 that can be charged with an insanely cheap board from that one site. [Franco] has all the code and files available, so go have fun making music without being turned off by a bunch of theory. Push that button there to check out the demo.

If ‘portable’ means pocket-sized to you, then let this mini woodwind MIDI controller take your breath away.

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Programmable Wrist Synth Pushes The Envelope

Synths are a ton of fun no matter how good or bad they sound. Really, there are no bad-sounding ones, it’s just that some are more annoying to listen than others to if you’re not the one making the beep boops. [Clem] had built a tiny LDR-based synth into a watch case a few years back and took it to many a Maker Faire, where it delighted and annoyed until it ultimately broke.

Naturally, it was time to make a new version that’s more capable. Whereas the first one was Atari-punk-console-meets-light-Theremin, this one has a bunch of inputs and can be programmed on the fly to record and play back bendable tones. It’s driven by an Arduino MKR, and the inputs are managed by an impressively squash bug-wired shift register. [Clem] used beefy switches this time in the hopes that this one will last longer. We think the slide pots are a great touch, as are the candy-colored knobs printed in PMMA.

Our favorite part is that [Clem] took advantage of the random states the microcontroller pins are in when it’s first powered on. If you don’t want to program any notes, you can use the ones generated at boot and just play around with those. Be sure to check out the build video after the break.

We’ve seen our share of synths, but few as delicious-looking as KELPIE from this year’s Hackaday Prize.

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