Solar Panel System Monitoring Device Using Arduino

[Carl] recently upgraded his home with a solar panel system. This system compliments the electricity he gets from the grid by filling up a battery bank using free (as in beer) energy from the sun. The system came with a basic meter which really only shows the total amount of electricity the panels produce. [Carl] wanted to get more data out of his system. He managed to build his own monitor using an Arduino.

The trick of this build has to do with how the system works. The panel includes an LED light that blinks 1000 times for each kWh of electricity. [Carl] realized that if he could monitor the rate at which the LED is flashing, he could determine approximately how much energy is being generated at any given moment. We’ve seen similar projects in the past.

Like most people new to a technology, [Carl] built his project up by cobbling together other examples he found online. He started off by using a sketch that was originally designed to calculate the speed of a vehicle by measuring the time it took for the vehicle to pass between two points. [Carl] took this code and modified it to use a single photo resistor to detect the LED. He also built a sort of VU meter using several LEDs. The meter would increase and decrease proportionally to the reading on the electrical meter.

[Carl] continued improving on his system over time. He added an LCD panel so he could not only see the exact current measurement, but also the top measurement from the day. He put all of the electronics in a plastic tub and used a ribbon cable to move the LCD panel to a more convenient location. He also had his friend [Andy] clean up the Arduino code to make it easier for others to use as desired.

Arduino Zero Pro Soft Release?

There’s an updated product page for the Arduino Zero, now called the Arduino Zero Pro, up on, one of the two dueling “Arduinos”.

We first covered the Arduino Zero in May 2014, and shortly thereafter even got to see a development prototype in the flesh. Based an Atmel’s ARM Cortex-M0+ chip, it’s built on a faster processor than the AVR Arduini, and it includes Atmel’s Embedded Debugger which serves as a USB-to-serial channel and on-chip debugging peripheral. But so far all we’ve seen is the prototype.

Now, there’s schematics and Eagle files available that are dated January 7, 2015. The site says that the Zero Pro is “Available now!” but we couldn’t see any in stock yet at any of our favorite online electronics distributors. Maybe we’re looking in the wrong places (unlikely) or maybe it’s just a matter of time.

Anyway, two things struck us in our casual perusal of the new Zero Pro info.

First of all, compared to (pictures of) the prototype versions, there’s more and larger decoupling capacitors scattered all over the board, from the power supply to the Embedded Debugger chip, to a really beefy 4.7uF tantalum capacitor buffering the analog reference voltage level. This suggests there’s been some real-world testing and a shakedown of some of the prototype’s design bugs. That’s all good, and we hope it’s a sign that it’s really coming to market soon.

Secondly, given the ongoing trademark dispute, even the annotations to the schematic for the Zero Pro become interesting. On opening up either the PDF schematic (PDF, naturally) or any of the Eagle files, there’s the usual “Do not finalize a design with this information” boilerplate. But where it used to read “Arduino is a registered trademark. Use of the ARDUINO name must be compliant with ” it now reads:

“Arduino” name and logo are trademarks registered by Arduino S.r.l. in Italy, in the European Union and in other countries of the world.

(After noticing this change, we went back and compared the “rev3″ Uno schematics PDF on to the “rev3E” schematics on Yup, same change in the legal notice.)

We’re not lawyers, but one of the “other countries of the world” that’s conspicuously missing from the claim is the U.S. of A. where Arduino LLC presumably holds the trademark. We’re still trying to make sense of all this, but it’s funny to see the legal battle playing itself out in annotations of Eagle schematics, no?

Stay tuned for more coverage of the Arduino vs Arduino legal battle and, of course, reviews of new hardware as it comes out.

And thanks [Marc] for the tip to the new board release.

Arduino Synth Guitar Really Rocks

[Gr4yhound] has been rocking out on his recently completed synth guitar. The guitar was built mostly from scratch using an Arduino, some harvested drum pads, and some ribbon potentiometers. The video below shows that not only does it sound good, but [Gr4yhound] obviously knows how to play it.

The physical portion of the build consists of two main components. The body of the guitar is made from a chunk of pine that was routed out by [Gr4yhound’s] own home-made CNC. Three circles were routed out to make room for the harvested Yamaha drum pads, some wiring, and a joystick shield. The other main component is the guitar neck. This was actually a Squire Affinity Strat neck with the frets removed.

For the electronics, [Gr4yhound] has released a series of schematics on Imgur. Three SoftPot membrane potentiometers were added to the neck to simulate strings. This setup allows [Gr4yhound] to adjust the finger position after the note has already been started. This results in a sliding sound that you can’t easily emulate on a keyboard. The three drum pads act as touch sensors for each of the three strings. [Gr4yhound] is able to play each string simultaneously, forming harmonies.

The joystick shield allows [Gr4yhound] to add additional effects to the overall sound. In one of his demo videos you can see him using the joystick to add an effect. An Arduino Micro acts as the primary controller and transmits the musical notes as MIDI commands. [Gr4yhound] is using a commercial MIDI to USB converter in order to play the music on a computer. The converter also allows him to power the Arduino via USB, eliminating the need for batteries.

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Arduino v. Arduino

Arduino LLC is suing Arduino Srl (the Italian version of an LLC). Sounds confusing? It gets juicier. What follows is a summary of the situation as we learned it from this article at (google translatrix)

Arduino LLC is the company founded by [Massimo Banzi], [David Cuartielles], [David Mellis], [Tom Igoe] and [Gianluca Martino] in 2009 and is the owner of the Arduino trademark and gave us the designs, software, and community support that’s gotten the Arduino where it is. The boards were manufactured by a spinoff company, Smart Projects Srl, founded by the same [Gianluca Martino]. So far, so good.

Things got ugly in November when [Martino] and new CEO [Federico Musto] renamed Smart Projects to Arduino Srl and registered (which is arguably a better domain name than the old Whether or not this is a trademark infringement is waiting to be heard in the Massachussetts District Court.

According to this Italian Wired article, the cause of the split is that [Banzi] and the other three wanted to internationalize the brand and license production to other firms freely, while [Martino] and [Musto] at the company formerly known as Smart Projects want to list on the stock market and keep all production strictly in the Italian factory.

Naturally, a lot of the original Arduino’s Open Source Hardware credentials and ethos are hanging in the balance, not to mention its supply chain and dealer relationships. However the trademark suit comes out, we’re guessing it’s only going to be the first in a series of struggles. Get ready for the Arduino wars.

We’re not sure if this schism is at all related to the not-quite-open-source hardware design of the Yun, but it’s surely the case that the company is / the companies are going through some growing pains right now.

Thanks [Philip Steffan] for the pointer to the MakeMagazin.DE article. (And for writing it.)

Is The Arduino Yun Open Hardware?

According to [Squonk42], nope. And we think he’s probably right.

The Yun is an Arduino Leonardo with an Atheros AR9331 WiFi SoC built in. It’s a great idea, pairing the Arduino with a tiny WiFi router that’s capable of running OpenWRT.  But how is this no longer Open Source Hardware? Try getting an editable board layout. You can’t.

Or at least [Squonk42] couldn’t. In Sept. 2013, [Squonk42] posted up on the Arduino forums requesting the schematics and editable design files for the Arduino Yun, and he still hasn’t received them or even a response.

Now this dude’s no slouch. He’s responsible for the most complete reverse-engineering of the TP-Link TL-WR703N pocket router, which is, not coincidentally, an Atheros AR9331-based reference design. And this is where the Arduini ran into trouble, [Squonk42] contends.

[Squonk42]’s hypothesis is that Arduino must have done what any “sane” engineer would do in this case when presented with a super-complex piece of hardware and a potentially tricky radio layout: just use the reference design (Atheros AP-121). That’s what everyone else in the industry did. And that’s smart, only the rest of the consumer electronics industry isn’t claiming to be Open Source Hardware while the reference design is protected by an NDA.

So it looks like Arduino’s hands are tied. They, or their partner Dog Hunter, either signed the NDA or downloaded the PDF of the reference design that’s floating around on the Interwebs. Either way, it’s going to be tough to publish the design files under a Creative Commons Attribution Share-Alike license.

Is this a change of strategy for the Arduino folks or did they just make a mistake? We won’t know until they respond, and that answer’s a year and a half in coming. Let’s see what we can do about that. And who knows, maybe Arduino can lean on Atheros to open up their reference design? It’s already an open secret at best.

But before you go out lighting up your righteous Open Source Hardware pitchforks and sharpening up your torches, read through [Squonk42]’s case and then dig through the primary sources that he’s linked to make up your own mind. You’ll make your case more eloquently if you’re making it yourself.

Good luck, [Squonk42]! We hope you at least get your answer. Even if you already know it.

Non-Arduino powered by a piece of Computing history

Sometimes it is a blessing to have some spare time on your hands, specially if you are a hacker with lots of ideas and skill to bring them to life. [Matt] was lucky enough to have all of that and recently completed an ambitious project 8 months in the making – a Non-Arduino powered by the giant of computing history – Intel’s 8086 processor. Luckily, [Matt] provides a link to describe what Non-Arduino actually means; it’s a board that is shield-compatible, but not Arduino IDE compatible.

He was driven by a desire to build a single board computer in the old style, specifically, one with a traditional local bus. In the early days, a System Development Kit for Intel’s emerging range of  microprocessors would have involved a fair bit of discrete hardware, and software tools which were not all too easy to use.

Back in his den, [Matt] was grappling with his own set of challenges. The 8086 is a microprocessor, not a microcontroller like the AVR, so the software side of things are quite different. He quickly found himself locking horns with complex concepts such as assembly bootstrapping routines, linker scripts, code relocation, memory maps, vectors and so on. The hardware side of things was also difficult. But his goal was learning so he did not take any short cuts along the way.

[Matt] documented his project in detail, listing out the various microprocessors that run on his 8OD board, describing the software that makes it all run, linking to the schematics and source code. There’s also an interesting section on running Soviet era (USSR) microprocessor clones on the 8OD. He is still contemplating if it is worthwhile building this board in quantities, considering it uses some not so easy to source parts. If you are interested in contributing to the project, you could get lucky. [Matt] has a few spares of the prototypes which he is willing to loan out to anyone who can can convince him that they could add some value to the project.

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Bill’s Arduino

Pokemon is a great game by itself, but when you realize that not all of the ‘mon are available in one game, trading is required for completion, and some pokemon aren’t available without either hacking or going to a Toys ‘R Us in 1997, you start to see how insidious this game can be. Figuring he could finally complete the game with an Arduino, [Pepijn] decided to build a pokemon storage system.

This build was inspired by an earlier post that also spoofed trades. Instead of building this project around a high-power micro, [Pepijn] decided to use an Arduino. The protocol Game Boys use to communicate with each other is extremely well documented, although that’s only half the battle. Each game using the link cable used specialized data structures for transfer, and after grepping through a disassembled Pokemon ROM,  [Pepijn] figured out how everything worked.

The completed hardware keeps one Pokemon in the EEPROM of an Arduino. It’s not very fast if you want to catch all 151 Pokemon in the Gen 1 games, but any way you look at it, you’re going to be catching a lot of Magikarp anyway.