Author: Brian McEvoy

267 Articles

Got Me Feeling Blue

March 29, 2020 by 22 Comments

Sleep schedules are an early casualty in the fight to be productive. Getting good sleep is an uphill battle, so anything that can help us is a welcome ally. We all know about the phone and computer settings that turn down the infamous blue hues at sunset, but what about when you want more blue light? Maybe you want to convince your body to stay awake to pre-acclimate for a trip across time zones. Perhaps you work or live in a place that doesn’t have windows. Menopause introduces sleep trouble, and that is a perilously steep hill.

[glowascii] takes the approach of keeping-it-simple when they arrange six blue LEDs under a flesh-tone patch, which isn’t fooling anyone and powers the lights with a USB power pack. Fremen jokes aside, light therapy is pricey compared to parts some of you have sitting in a drawer. Heck, we’d wager that a few of you started calculating the necessary resistor sizes before you read this sentence. Even if you don’t need something like this, maybe you can dedicate an afternoon to someone who does.

DIY therapy has a special place in our (currently organic) hearts, such as in this rehabilition glove or a robot arm.
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Ondophone On Point

March 28, 2020 by 5 Comments

The name Ondophone is a mash-up of two instruments, the Marxophone, and the ondes martenot. From the Marxophone, [Wintergatan] borrows the spring-loaded hammers, which repeatedly strike a string once activated. The ondes martenot loans its Theremin-like sound and ability to lean back on western semi-tone notes. Mating such different instruments requires a team, and much like the name, it produces a splendid blend.

At the left-hand side of the Ondophone, we see the spring-hammer battering away on a steel string whenever the neck moves up or down. Next to it is an Ebow that vibrates a string with an electromagnet and can maintain a note so long as it has power. Hidden within the neck are magnets to demarcate semi-tone locations, so it’s possible to breeze past them for a slide sound or rest on them to follow a tune.

The combination of intermittent hammering and droning lends well to the “creepy” phase of the song, which leads segues to the scope-creep that almost kept this prototype on the drawing board. The video talks about all the things that could have been done with this design, which is a pain/freedom we know well. KISS that Ondophone headline act goodbye.

The ondes martenot is an early electronic instrument, so we’ve some high-tech iterations, and if you haven’t heard what’s possible with a DIY Ebow, we will harp on you.

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A Tin Can Phone, But With Magnets

February 29, 2020 by 17 Comments

The tin can phone is a staple of longitudinal wave demonstrations wherein a human voice vibrates the bottom of a soup can, and compression waves travel along a string to reproduce the speaker in another can at the other end. All the parts in this electrical demonstration are different, but the concept is the same.

Speakers are sound transducers that turn electrical impulses into air vibrations, but they generate electricity when their coil vibrates. Copper wires carry those impulses from one cup to another. We haven’t heard of anyone making a tin can phone amplifier, but the strictly passive route wasn’t working, so an op-amp does some messy boosting. The link and video demonstrate the parts and purposes inside these sound transducers in an approachable way. Each component is constructed in sequence so you can understand what is happening and make sense of the results.

Can someone make a tin can amplifier transformer? We’d like to see that. In another twist of dual-purpose electronics, did you know that LEDs can sense light?

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The Smallest Cell Phone Picture

February 23, 2020 by 14 Comments

Mobile phones are the photography tool for most of us, but they are a blunt tool. If you love astrophotography, you buy a DSLR and a lens adapter. Infrared photography needs camera surgery or a special unit. If you want to look closer to home, you may have a microscope with a CCD. Your pocket computer is not manufactured for microscopy, but that does not mean it cannot be convinced. Most of us have held our lens up to the eyepiece of some binoculars or a microscope, and it sort of works, but it is far from perfect. [Benedict Diederich] and a team are proving that we can get darn beautiful images with a microscope, a phone holder, and some purpose-built software on an Android phone with their cellSTORM.

The trick to getting useful images is to compare a series of pictures and figure out which pixels matter and which ones are noisy. Imagine someone shows you grainy nighttime footage from an outdoor security camera. When you pause, it looks like hot garbage, and you can’t tell the difference between a patio chair and a shrubbery. As it plays, the noisy pixels bounce around, and you figure out you’re looking at a spruce bush, and that is roughly how the software parses out a crisp image. At the cost of frame rate, you get clarity, which is why you need a phone holder. Some of their tests took minutes, so astrophotography might not fare as well.

We love high-resolution pictures of tiny things and that isn’t going to change anytime soon.

Thank you [Dr. Nicolás De Francesco] for the tip.

What Does Your Necklace Say?

February 17, 2020 by 2 Comments

If we write about sound reproduction, there is a good chance we found a home-made amplifier or an upcycled speaker system. In this case, you don’t use your ears to appreciate the sound; you use your hands or eyes. [ElatisEagles] converted an amplitude sound graph into a wearable bead. Even without much background it should be immediately recognizable for what it is. Presumably, they converted a sound wave to vectors, then used the “Revolve” function in Rhino, their software of choice. Sometimes this is called a “lathe” function. Resin printers should be able to build these without supports and with incredible fidelity.

Some tattoos put a sound wave on the skin, and use an app to play it back, but if you want to wear a sound bite from your favorite show and not get branded as the “Pickle Rick” gal/guy at the office, maybe swap out the color and sound wave before it goes stale. We would wear a bead that says, “drop a link in our tip line,” but you can probably think of something more clever.

We have other high-tech ornamentation that leverages motion instead of sound, or how about a necklace that listens instead.

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NFC For Your Home Automation

January 30, 2020 by 26 Comments

If home automation in the IoT era has taught us anything, it is that no one wants to run wires. Many of us rent, so new cabling is not even an option, even if we wanted to go that route. If you want a unique sensor, you have to build your own, and [tmkThings] wanted an NFC scanner at his front door. Just like arriving at work, he scans his credentials, and the door unlocks automagically.

Inside a little white box, we find an ESP8266 speaking Wifi attached to a PN532 talking NFC, and both are familiar names on these pages. The code, which is available on GitHub, links up with IFTTT and MQTT. For the security-minded, we won’t see this on your front door, but you can trigger your imagination’s limit of events from playing your favorite jams at the end of the day to powering down all the televisions at bedtime.

NFC hacks are great because they are instantly recognizable and readers are inexpensive, but deadbolt hacking is delightful in our books.

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Fabric(ated) Drum Machine

January 7, 2020 by 3 Comments

Some folks bring out an heirloom table runner when they have company, but what if you sewed your own and made it musical? We’d never put it away! [kAi CHENG] has an Instructable about how to recreate his melodic material, and there is a link to his website, which describes his design process, not just the finished product. We have a video below showing a jam session where he exercises a basic function set.

GarageBand is his DAW of choice, which receives translated MIDI from a Lilypad. If you don’t have a Lilypad, any Arduino based on the ATmega328P chip should work seamlessly. Testing shows that conductive threads in the soft circuit results in an occasional short circuit, but copper tape makes a good conductor  at the intersections. Wide metallic strips make for tolerant landing pads beneath modular potentiometers fitted with inviting foam knobs. Each twist controls a loop in GarageBand, and there is a pressure-sensitive pad to change the soundset. Of course, since this is all over MIDI, you can customize to your heart’s content.

MIDI drums come in all shapes and sizes, from a familiar game controller to hand rakes.

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