The Hacklet #7 – MIDI

July 11, 2014 by Adam Fabio 14 Comments

This week’s Hacklet is all about Hackaday.io projects which use MIDI, or Musical Instrument Digital Interface for the uninitiated. MIDI was designed from the ground up as an open communications standard for musical instruments. Nearly every major instrument company participated in the design of the standard. MIDI was first demonstrated in January of 1983, with the communications standard document following in August. Hackers, makers, and musicians immediately ran with it, using MIDI to do things the designers never dreamed of.

[Robert’s] 9×9 Pixel Muon Detector/Hodoscope is a great example of this. [Robert] is using 18 Geiger Muller Tubes to detect cosmic particles, specifically muons. The tubes are stacked in two rows which allows him to use coincidence detection. Rather than just plot some graphs or calculate impact probabilities, [Robert] hacked a Korg Nanokey 2 MIDI controller to output MIDI over USB messages corresponding to the detected muons. Check out his video to see a sample of the music of the universe!

Next up is [Michele’s] DIY MPC style MIDI controller. [Michele] needed a simple low-cost drum controller that wouldn’t wake his neighbors. He loved Akai MPC controllers, so he rolled his own. [Michele] investigated force sensitive resistors but found they were very expensive. At a cost of $8 USD each, his resistors alone would be nearly the cost of a low-end MPC! [Michele] created his own sensitive pads using a sandwich of copper tape and 3M Velostat conductive sheets. An HCF4067 routes all the analog lines to a single pin of Teensy 3.0, which then converts the analog resistor outputs to MIDI messages.

[Johan] loves his analog synths, and wanted them to be able to talk MIDI too. He built MIDI2VC, a circuit which converts MIDI to 1V/Octave (similar to CV/Gate). 1V/Octave is an analog control system used in some early synthesizers, as well as many modern analog creations. Pitches are assigned voltages, and as the name implies, each octave is 1 volt. A4 on the keyboard is represented by 4 volts, while A5 is 5 volts. [Johan] used a Microchip PIC16LF1823 to receive and convert the MIDI signals. The PIC outputs I2C data to an MCP4725 DAC which drives the analog side of the house.

Long before DMX512 came on the scene, hackers were controlling lights via MIDI. [Artis] continues this with El Dance, a wireless system for controlling electroluminescent wire worn by dancers. Similar in function to [Akiba’s] EL wire system, [Artis] took a lower cost route and used the venerable NRF24L01 radio module. He added an antenna which gives the modules a range of about 30 meters. The computer running the dance routine’s music sees the transmitter side of the link as a MIDI instrument. Standard note on and off commands activate the EL wire strings.

Our final hack comes from [Jen] who built a MIDI Vibrator Inductor Synth. [Jen] performs in an experimental music band called My Wife, with instruments as varied as violins and sewing machines. [Jen] must be a fan of Van Halen’s Poundcake as she’s using a similar technique, with a MIDI twist. An Arduino converts MIDI notes to analog values, which are sent to a motor controller board. The motor controller uses PWM to drive a vibrator motor at the frequency of the note being played. Like all DC motors, the vibrator puts out a ton of electromagnetic noise, which is easily picked up by [Jen’s] electric bass.

That’s it for this week’s Hacklet! Tune in next week for more projects from Hackday.io!

THP Hacker Bio: Nsted

July 10, 2014 by Mike Szczys 5 Comments

thp-contestant-bio-nsted

Have you ever wanted to build a robot arm, or even a full robot, but were put off by the daunting task of making all of those articulations work? Moti could make that a lot easier. The project seeks to produce smart servo motors which can connect and communicate in many different ways. It’s a great idea, so we wanted to know more about the hacker behind the project. After the jump you’ll find [nsted’s] answers to our slate of question for this week’s Hacker Bio.

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Droning On: PID Controllers And Bullet Connectors

July 7, 2014 by Adam Fabio 30 Comments

Not all drones are multirotors – Posing in our title photo are Maynard Hill and Cyrus Abdollahi. Maynard’s plane, TAM5 aka The Spirit of Butts Farm, is the smallest aircraft to make a transatlantic flight (YouTube link). Retracing the path of Alcock and Brown from Newfoundland to Ireland, the 6 pound (dry weight) model made the trip in just under 39 hours. All this happened in 2003, and was the cap on a lifetime of achievements for Hill. These are the types of pursuits that will be banned in the USA if the FAA restrictions go into effect.

Flight Controllers

Quite a few of you thought the Naze32 was left out of last column’s flight controller roundup. I hear you loud and clear! I’ll add the Naze to the controllers which will be tested on The Hackaday Testbed. The hard part is finding the darn things! I currently have an Acro Naze32 on its way to Droning On HQ. If I can find a full version, I’ll add that.

PID Controllers Deep Dive

I’ve gotten a few questions on Proportional Integral Derivative (PID) controllers, so it is worth diving in a bit deeper to explain what a PID controller is. PID controllers are often found in process controls managing parameters like temperature, humidity, or product flow rate. The algorithm was initially designed in the late 1800’s as a method of controlling the helm of large naval ships. In fixed wing drones, PID keeps the plane’s wings level and on course. In multicopters, PID loops control heading, but they also provide the stable flight which allows the quadcopter to fly in the first place. A full explanation of PID loops would be beyond the scope of a single article, but let’s try a 10,000 foot explanation.

P: This is the “Present” parameter. P Has the most influence on the behavior of the aircraft. If the wind blows your quadcopter from level flight into a 30 degree right bank, P is the term which will immediately take action to level the quad out. If the P value is too high, The quadcopter will overshoot level flight and start banking the other way. In fact, way too high a P value can cause a quadcopter to shake as it oscillates or “hunts” for level. Too Low a P value? the quadcopter will be very slow to react, and may never quite reach level flight again.

I: This the “Past” parameter. The I term dampens the overshoot and oscillations of the P term, and avoids the tendency of P to settle above or below the set point. Just like with P, too high an I term can lead to oscillation.

D: This is the “Future” parameter, and has the smallest impact on the behavior of the aircraft. In fact, some flight controllers leave it out entirely. If P and I are approaching a set point too quickly, overshoot is likely to occur. D slows things down before the overshoot happens.

So why do multicopter pilots dread PID tuning? Quite simply, it’s a tedious process. Couple a new pilot and an unproven aircraft with un-tuned PID values, and you have a recipe for frustration – and broken propellers. Things get even more complex when you consider the fact that there are at least 3 sets of PID variables to be tuned – Pitch, Roll, and Yaw. Some flight controllers now support multiple PID values depending on the style of flight. Want your plane or multicopter to fly around like a hotrod? You need a totally different set of PID values than a docile trainer craft. Rolf Bakke (KapteinKUK himself) made a video illustrating how multicopters behave when tuning PID values. You can easily see how a quad can go from “drunk” to “angry bee” with just a few value tweaks. All this is coming together with The Hackaday Testbed, which will help me in posting a few PID tuning videos of my own.

Hackaday Testbed Update

As for the testbed itself, it’s nearly complete! You can follow the progress on my Hackaday Projects Page. Most of the assembly has been relatively straightforward. though of course there are always a few snags. It seems I always forget something when ordering up parts for a build. In this case it was 2.5mm banana plugs and motor mounting screws.

The Hobbyking motors attach to the frame with 3mm screws. The problem is that there really is no way to know how long the screws should be until you have the motors, mounting plates and drone frame on hand. I have a bunch of 3mm screws of various lengths, and thankfully there were enough screws of the correct length to mount the motors. Murphy is always at my side, as I accidentally grabbed a screw that was 1mm too long and, you guessed it, screwed right into the windings of the motor. Doh! Thankfully I had spares.

Bullet connectors can be a real pain to solder. There are some jigs out there which help, but I’ve always found myself going back to the old “helping hands” alligator clips. Bullets tend to use lower gauge wire than we’re used to with regular electronics. 14, 12, even 8 gauge wires are used on R/C aircraft. A low power soldering iron with a surface mount tip just won’t cut it. Those irons just doesn’t have the thermal mass to get the connectors up to soldering temperature. This is one of those places where a decent 40 watt or better Weller iron (yes, the kind that plugs right in the wall) can be a godsend. I’m using an Metcal iron here, with a wide flat tip.

Bare bullet connectors and alligator clips can also create a problem – the metal clips create even more thermal mass. Years back an old-timer showed me a trick to handle this. Slip a piece of silicone R/C plane fuel tubing on the bullet, and then clip the helping hands onto the tube. The tube will act as insulation between the bullet and the clip. Silicone can easily withstand the temperatures of soldering. I’ve also used the silicone tube on the jaws themselves – though eventually the jaws will cut the soft tubing.

That’s about it for this edition Droning on! Until next time, keep ’em flying!

Title photo credit Cyrus Abdollahi.

Ask Hackaday: Global Energy Transmission – Can It Work?

July 7, 2014 by Will Sweatman 177 Comments

Atop a small mountain in Colorado Springs sat the small, makeshift laboratory of Nikola Tesla. He chose this location because the air was thinner, and therefor more conductive. Tesla had come to believe that he could use the Earth as a conductor, and use it to send electrical power without the need for wires. Though some facts are forever lost, it is said that on a clear, moonless night, Tesla flipped the switch that fed millions of volts into a large coil that towered high into the air. He cackled maniacally as an eerie blue corona formed around the crackling instruments, while some 200 florescent bulbs began to glow over 25 miles away.

A magnificent feat took place in the hills of Colorado that night. A feat that surely would change the world in how it harnessed electricity. A feat that if brought to its full potential, could provide wireless power to every point on the globe. A feat that took place almost one hundred and twenty years ago…

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Hackaday Links: July 6, 2014

July 6, 2014 by Brian Benchoff 43 Comments

Power for your breadboards. It’s a USB connector, a 3.3V voltage regulator, and a few pins that plug into the rails of a breadboard.

“Have you seen those ‘Portable battery chargers for smartphones?’ Well the idea of the device is based on it , but the difference here is the internet part.” That’s a direct quote from this Indiegogo campaign. It’s funny because I don’t remember losing my damn mind recently. Wait. It’s $200. Yep. Yep. Definitely lost my mind there.

Putting the Internet on a USB stick not weird enough? Hair Highways. Yep, human hair. It’s just embedding human hair into resin, cutting everything up into plates, and assembling these plates into decorative objects. As a structural material, it’s probably only as strong as the resin itself, but with enough hair set in layers perpendicular to each other, it would be the same idea as fiberglass. Only made out of hair.

Tesla is building a $30,000 car and Harley is building an electric motorcycle. The marketing line for the bike will probably be something like, “living life on your own terms, 50 miles at a time”.

PixelClock? It’s a 64×64 array of red LEDs built to be a clock, and low-resolution display. It looks blindingly bright in the video, something that’s hard to do with red LEDs.

The Hacklet #6 – Lasers

July 4, 2014 by Adam Fabio 10 Comments

This week’s Hacklet is all about lasers, which have been shining a monochromatic light for hackers since 1960. The first working laser was demonstrated by [Theodore Maiman], who was a hacker / maker himself, having learned circuits in his father’s home electronics lab. It’s no surprise that lasers have been hugely popular in the hacker community ever since.

[Maiman’s] first laser was pumped with flash tubes, which is similar to the YAG laser in [macona’s] project to restore a laser welder. He’s gotten his hands on a 1985 model 400W Lumonics laser welder. This welder was originally bought by Tektronix to weld titanium CRT flanges. Time moved on, and the welder was sold to [macona’s] company, who used it until the Anorad control system died. There was an effort to bring it up to date with new servos and an OpenCNC control system, but the job was never finished. This laser sat for 12 years before [macona] bought it, and now he’s bringing it back to life with LinuxCNC. The project is off to a blazing start, as he already has the laser outputting about 200 Watts.

On the slightly lower power side of things we have [ThunderSqueak’s] 5mW visible red (650nm) laser. [ThunderSqueak] needed an alignment laser with decent focusing optics for her other projects. She mounted a module in a plastic case and added a switch. A quick build, but it’s paying dividends on some of her bigger projects – like her Low Cost CO2 Laser Build, which we featured on the blog back in May.

[phil] used buildlog 2.x as the inspiration for his Simple DIY laser cutter. The laser power comes from a low cost K40 laser tube and head. His frame is aluminum extrusion covered with Dibond, an aluminum composite material used in outdoor signs. Locomotion comes from NEMA 17 stepper motors. Many of [phil’s] parts are machined from HDPE plastic, though it looks like they could be 3D printed as well. We bet this one will be a real workhorse when it’s done.

[ebrithil] is working on a combo laser engraver/PCB etcher which will use a solid state laser module. His layout is the standard gantry system seen on many other mills and 3D printers. Dual steppers on the Y axis increase avoid the need for a central belt. His Z axis was donated by an old DVD drive. It has enough power to lift a pen, and should be plenty accurate for focusing duty. He’s already run a couple of great tests with a low power violet laser and glow in the dark material.

[Mario] is creating an incredibly versitile laser tool in his OpenExposer, which can do everything from stereolithography 3D printing to making music as a laser harp. The genius here is [Mario’s] reuse of laser printer parts. Every laser printer uses the same basic setup: a laser, a scanning mirror, and optics to stretch the beam out to a full page width. [Mario] is already getting some great prints from OpenExposer. This project is one to watch in The Hackaday Prize.

[fl@C@] is digging into the physics side of things with his DIY 3D Printable RaspberryPi Raman Spectrometer. Raman Spectrometers are usually incredibly expensive pieces of requirement which can tell us which elements make up a given material sample. [fl@C@’s] laser is a 532nm 150mW laser, which bounces through a dizzying array of mirrors and lenses. The resulting data is crunched by a Raspberry Pi to give a full spectrographic analysis. [fl@C@’s] entered his project in The Hackaday Prize, and we featured his bio back in June.

That’s it for this week’s Hacklet, until next week, don’t just sit around wondering why aren’t lasers doing cool stuff. Make it happen, and post it up on Hackaday.io!

Fail Of The Week: Blown Light Bulb Controllers

July 3, 2014 by Mike Szczys 29 Comments

fotw-nyc-resistor-chandelier-driver

We’ve been meaning to get around to this one for many weeks now. It’s been hard to find good fail write-ups… it’s as if hackers are afraid to admit that sometimes projects fail. We hope you’ll shake off that opinion as failure is the fastest path for learning and true understanding!

[xymax] was working on a control system for a chandelier with 150 bulbs which use 5 Watts each. This project was being readied for the NYC Resistor Interactive Party which [Adam Fabio] attended last month. As deadline for the show approached, the last piece was put in place late into the night… but it was connected backwards. In a tale worthy of a slapstick movie, the reverse polarity caused a chip on all seven controller boards for this module to blow like the one seen above. But that’s not all, the laptop being used during prototyping was connected by USB and started smoking!

All of us feel the pain of this type of equipment failure. Luckily [xymax] looked for lessons to learn instead of dwelling on the mistake itself. Use protection diodes, keyed connectors, and write about your failures. Hopefully reading this will help others avoid a similar equipment-destroying mistake.

Fail of the Week is a Hackaday column which runs every Thursday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.