Arduino Hacks

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The Internet Of Linux Things

February 25, 2016 by 43 Comments

The Linux Foundation is a non-profit organization that sponsors the work of Linus Torvalds. Supporting companies include HP, IBM, Intel, and a host of other large corporations. The foundation hosts several Linux-related projects. This month they announced Zephyr, an RTOS aimed at the Internet of Things.

The project stresses modularity, security, and the smallest possible footprint. Initial support includes:

  • Arduino 101
  • Arduino Due
  • Intel Galileo Gen 2
  • NXP FRDM-K64F Freedom

The project (hosted on its own Website) has downloads for the kernel and documentation. Unlike a “normal” Linux kernel, Zephyr builds the kernel with your code to create a monolithic image that runs in a single shared address space. The build system allows you to select what features you want and exclude those you don’t. You can also customize resource utilization of what you do include, and you define resources at compile time.

By default, there is minimal run-time error checking to keep the executable lean. However, there is an optional error-checking infrastructure you can include for debugging.

The API contains the things you expect from an RTOS like fibers (lightweight non-preemptive threads), tasks (preemptively scheduled), semaphores, mutexes, and plenty of messaging primitives. Also, there are common I/O calls for PWM, UARTs, general I/O, and more. The API is consistent across all platforms.

You can find out more about Zephyr in the video below. We’ve seen RTOS systems before, of course. There’s even some for robots. However, having a Linux-heritage RTOS that can target small boards like an Arduino Due and a Freedom board could be a real game changer for sophisticated projects that need an RTOS.

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A Slew Of Open-Source Synthesizers

February 23, 2016 by 57 Comments

Hackaday reader [Jan Ostman] has been making microcontroller-based DIY synthesizers for quite a while now. Recently, he’s opened up the source for a lot of them so that you can play along at home. All of these virtual-analog synths and soundmakers can be realized on an Arduino or AVR ATmega328 if you happen to have one lying around.

Extra parts like a keyboard, some pushbuttons, or some potentiometer knobs to twiddle won’t hurt if you’d like to make something more permanent or more obviously playable, like [Jan] does. On the other hand, if you’d just like to get your feet wet, I’ve tweaked his code to be more immediately plug-and-play. The code is straightforward enough that it’s a good learning platform. So let’s take a quick tour through three drum machines and a string synth, each of which you can build on a breadboard in just a few minutes.

To install on an Arduino UNO, fetch the zip file from this GitHub repository, and move each subfolder to your Arduino sketch directory. You’re ready to play along.

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Lego Nuclear Reactor Uses Arduino

February 22, 2016 by 45 Comments

Before the NSA deletes this post, we’ll be clear: We’re talking about a model of a nuclear reactor, not the real thing. Using Legos, [wgurecky] built a point kinetic reactor model that interfaces with the reactor simulator, pyReactor.

Even without the Lego, the Python code demonstrates reactor control in several modes. In power control mode, the user sets a power output, and the reactor attempts to maintain it. In control rod mode, the user can adjust the position of the control rods and see the results.

If things get out of hand, there’s a SCRAM button to shut the reactor down in a hurry. The Lego model uses an Arduino to move the rods up and down (using a servo) and controls the simulated Cherenkov radiation (courtesy of blue LEDs).

We’ve been excited to see more high schools with significant engineering programs. This would be a good project for kids interested in nuclear engineering. It certainly is a lot safer than one of our previous reactor projects.

Ski Buddy Jacket Uses Arduino To Teach Youngsters To Ski

February 22, 2016 by 2 Comments

Snow skiing looks easy, right? You just stay standing, and gravity does the work. The reality is that skiing is difficult for beginners to learn. [19mkarpawich] loves to ski, but he was frustrated seeing crying kids on skis along with screaming parents trying to coach them. Inspired by wearable electronics, he took an Arduino, an old jacket, some LEDs, and created Ski Buddy.

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Home-Made Solenoid Motor

February 19, 2016 by 28 Comments

Want to really understand how something works? Make one yourself. That’s the approach that Reddit user [Oskarbjo] took with this neat electric motor build. He made the whole thing from scratch, using an Arduino, 3D printing, and ample quantities of wire to create a solenoid motor. This transforms the linear force of a solenoid, where a magnet is moved by a magnetic field, into rotary force. It’s rather like an internal combustion engine, but driven by electricity instead of explosions. Hopefully.

[Oskarbjo]’s engine seems to work, including a rather neat mechanism to detect the rotation of the shaft and relay that back to the controller. He hasn’t posted much detail in the build process, unfortunately, but did say that “If you’d want to build something similar I can probably help you out a bit, but half the fun is coming up with your own solutions.” Amen to that. We’ve seen a few neat solenoid motor builds, but this one wins points for starting from scratch. There is an Instagram video of the motor running after the break.

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Ridiculously Automated Dorm Room

February 13, 2016 by 22 Comments

Take three NRF24L0+ radios, two Arduino Nanos, and a Raspberry Pi. Add a bored student and a dorm room at Rice University. What you get is the RRAD: Rice Ridiculously Automated Dorm. [Jordan Poles] built a modular system inspired by BRAD (the Berkeley Ridiculously Automated Dorm).

RRAD has three types of nodes:

  • Actuation nodes – Allows external actuators like relays or solenoids
  • Sensory nodes – Reports data from sensors (light, temperature, motion)
  • Hub nodes – Hosts control panel, records data, provides external data interfaces

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Constant Innovation And Useless Ducks

February 9, 2016 by 15 Comments

[Mike]’s hacks aren’t breathtaking in their complexity, but they got a good chuckle out of us. [Mike], the CEO of The Useless Duck Company, lives in a hub of innovation somewhere in Canada, where he comes up with useful gadgets such as a Fedora that tips itself, or a door that locks when you’re shopping for gifts for your wife and you’re in incognito mode.

It all started when he was trying to learn the Arduino, and he put quite a few hours into making a device that could wirelessly squeak a rubber bath duck from the bathroom. The whole project reminded us of our first clumsy forays into the world of electronics, with entirely too many parts to complete a simple function. The Arduino being the gateway drug it is, it wasn’t long before he was building a bartending robot.

We hope he continues to construct more entertaining gadgets.

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