Enginursday: Exploring the Arduino/Intel Galileo


The list of official Arduino boards continues to grow, and, continuing with the famous-Italian-person trend, now includes the Galileo. The Galileo is Intel’s toe-dip into the Arduino waters. It features their Quark SoC X1000 – a 32-bit, x86 system-on-a-chip that can run at up to 400MHz with 512 kB of built-in SRAM.

Galileo product shot

The Galileo board supports the Quark with a wide range of external peripherals. There’s 8MB Flash (to store firmware), 11kB EEPROM, a µSD socket (supports up to 32GB), 10/100Mb Ethernet, USB 2.0 host and device ports, an RS-232 port, and a mini PCI Express (mPCIE) socket. On top of all that, it’s got that same, familiar Arduino pinout we all love (to hate?). The Arduino pins – including six analog inputs, SPI, I2C, UART, and PWM outputs – are all exactly where an Arduino user would expect them to be.

What the Galileo tries to do is meld the ease of Arduino’s hardware manipulation with the power of a Linux operating system. Most sketches written for Arduino Unos, Leonardos, and other boards can be ported directly over to the Galileo. You can still use popular Arduino libraries like SD, Ethernet, WiFi, EEPROM, SPI, and Wire, but you can also make requests of the Linux kernel with system() calls. This gives your Arduino sketch access to powerful utilities like Python, Node.js, OpenCV, and all sorts of fun Linux-y stuff.

Unread-Email-Checker Example Project

We were fortunate enough to receive a couple of early Galileo boards for evaluation, one of which landed in my hands to futz around with. To get a feel for the board, I tried to whip together a quick project that melded a few of the Galileo’s unique features together.

Most of our work communication occurs in emails, but I’m often turned away from my computer, wielding a soldering wand or banging my head against my Pi workstation as those emails pile up. It’s imperative that I stay up-to-date with the latest SparkFun memes and cool robot videos, so a simple unread-email-counter would be great to have permanently installed over my workbench. Sounds like a perfect project for the Galileo!

First, I needed a utility to check how many unread emails I have. Well, I don’t need much of an excuse to whip out some Python, so I did a quick search and found the script below. It logs into our email server with my credentials, checks how many unread emails there are in the inbox, and prints that value.

I loaded that onto a µSD card (also including the Galileo’s SD-bootable “bigger” Linux image, required for Python), and proceeded to the next task.

To display the email count (and retain the Arduino-y-ness of the Galileo) I used an OpenSegment Shield, controlled over SPI. No modifications, just plop it right on top of the Galileo. A lot of the Arduino code below might look familiar, especially if you’ve used the SPI, SD, or WiFi libraries, which all work swimmingly with the Galileo.

One of the key, uniquely-Galilean functions this code incorporates is the system() function, which can issue requests to the Linux kernel. With the below line of code, we can run a Python script from the comfy confines of Arduino:

system("python /media/realroot/pyMail.py > /media/realroot/emails");

The output of the script is routed to a file named “emails.” Then we can use the Arduino SD library to read the “emails” file, which simply contains the number of unread emails there are. After a bit of parsing, and SPI-ing, we’ve got an unread email count printed to the OpenSegment Shield!

Galileo unread email checker project photo

(Now if only I could program it to answer those emails…)

First Impressions

After toying around with the board for a few days, here are a few of my thoughts on the pros and cons of the Galileo:

Likes

  • Life is pretty sweet on the Arduino half of the Galileo. Setup is about as easy as any other Arduino board, most shields should be supported (though watch out for that 3.3V operating voltage), and a lot of sketches can be ported directly over to a Galileo. Plus, there’s a ton of SRAM; you can include memory-hungry libraries and mess with strings and large buffers with little worry of exhausting your memory supply.
  • A sketch’s ability to interact with the Linux kernel via system calls leaves the door open for a lot of nifty hacks.
  • For those who want to directly interact with Linux, a terminal is available via the on-board RS-232 port. Or you can even SSH into the board if it’s set up on a network.
  • The mini PCIE socket certainly makes it unique among modern SBC’s. Though it seems like, generally, it’ll be used for WiFi, perhaps it can be used to drive video, audio, SATA, or other interfaces.
  • It’s open-source! You can check out the schematics or even the board design files. While you may not be designing a Quark-based board any time soon, there’s still a lot to learn from these documents.

Dislikes

  • In comparison to other Arduino boards (fair or not) the documentation is limited and the community still seems to be in its infancy. The getting started guide is a good place to start; after that you may be relegated to forum searching/posting.
  • The recommended Linux distribution is limited. Don’t go in expecting anything like a flavor of Debian (no apt-get makes for a sad Linux-newbie). I definitely recommend throwing an SD card in there with the “big” Linux image, which adds WiFi support as well as the fun stuff like Python, SSH, node.js, ALSA, V4L2, and openCV.
  • The maximum I/O speed on most pins is around 230 Hz, which may be a problem for some applications. There are a couple pins capable of faster speeds (~3MHz), and that limit doesn’t have effect on the UART, SPI, or I2C clocks.
  • A personal nitpick: to interact with the Linux terminal, one of the Galileo’s UARTs is converted, on-board, to RS-232 and sent out through a 3.5mm “stereo” jack. To connect that up to my computer, I need a weird combination of 3.5mm-to-DB9 RS-232 cable, and then a RS-232-to-USB cable to my computer. It works, but I’d rather it just output a simple TTL UART signal, which I can convert as I please.

The Galileo is a unique entry into the growing Arduino board catalog. I’m sure there are plenty of projects out there that can make use of the unique blend of Arduino and Linux. Is the Galileo ever going to unseat the Raspberry Pi? Probably not. But they both serve their own, unique purpose. The Pi, with its HDMI output, gives you a complete, mini-computer, while the Galileo is more of a hardware-focused platform, with a smaller Linux backbone (and Arduino shield compatibility!).

Have you had a chance to play with the Galileo yet? What are your thoughts? Looking to pick one up? It looks like availability is beginning to increase; I hope to see the Galileo community continue to grow, and seed more projects that can make use of the board.


Comments 35 comments

  • On the shield compatibility: looking over Intel’s schematics for the Galileo there is a jumper to select 3.3v or 5v as the IOREF voltage, so it should be compatible with all existing shields from a “doesn’t smoke when hooked up” perspective

    I think a more notable limitation is that the power supply input must be 5v and is not able to handle the 7-12v DC that many other Arduinos use.

    • Other than voltage, there are other issues with compatibility. Mainly I/O pin speed. For instance, the DHT11 sensor cannot be used with a Galileo board, because the I/O speed is too slow. https://communities.intel.com/message/216870#216870

      I am not sure if any of the Ethernet, WiFi, or SD card shields would work. But using the onboard Ethernet and SD card work. Also adding in a mPCIe WiFi card allows you to use the WiFi like you would with a shield. So, really there is no need for those shields on Galileo.

  • So, when will SparkFun be carrying Galileos?

    • Soon-ish…? We will be carrying them at some point, but don’t have a firm date. We did spend some time talking with them at CES about the Galileo and the forth-coming Edison. Stay tuned for more…

  • Where can I find out more about the system() call? Or how about a search string that doesn’t return everything Arduino?

    • system() is a common C/C++ function call that forks a shell, run the command on the OS and returns the exit status. Arduino don’t have it because they don’t have an OS aside from the boot loader and uploaded code. Galileo having a version of Linux installed means it can run commands from inside your program.

  • I could use that unread email counter for my wife’s email, but sadly I don’t think a 4 digit display is enough. :-)

  • The feature that makes me chomp at the proverbial bit to get my hands on one is that it has a connector for a battery to back up the built-in RTCC, something that is missing on both the Raspberry Pi and the Beaglebone Black. Many (most) of my uses for this class of computers have an absolute requirement for a battery-backed Real Time Clock Calendar.

    I was bemoaning the fact that I’ve had one “on order” (from Mouser) since November, and they keep pushing the ship date out, to my colleagues at the IEEE Computer Society last night. Their general consensus was that I should start a pool on whether or not it would be “on the shelves” this year (which only gives them 356 days), given Intel’s history. (In my career, I’ve mostly not been dependent on having the “latest and greatest” from Intel.)

    • You can buy it today from several other distributors. https://communities.intel.com/thread/47443

    • About the battery-backed RTC, have you seen the Radxa Rock? It is a heavyweight board in this class, with quad-core and 2GB RAM.

    • FWIW, I just got an e-mail saying that Mouser shipped it today. (I’d selected the “Economy Shipping”, so the “expected deliver date” is 20-JAN-14.)

      • The UPS tracking says it should be here 15-Jan-14. Guess our friends at Mouser are expecting an ice storm between Ft. Worth and Phoenix. :-)

        • Two more tidbits: the price on the invoice was $69.00 plus shipping, and it came with an “international” wall-wart rated at 2.0A (at 5V) output. The “safety and regulatory information” pamphlet has 34 languages.

        • OK, if anyone picked “14-Jan-14” in the pool as to when my Galileo actually showed up on my door step, you won! :-) (Don’t you love people who reply to their own reply to their own postings?)

    • I was able to order one from Newegg and get it within a couple of days, I have no idea what Mouser’s problem is getting them in stock.

  • It looks like there isn’t much point in coding on this board with arduino - much better to use an SD card & write code in C that can make full use of the board’s IO & speed (Given that some people are claiming this is about 200 times SLOWER than an AVR based arduino)

  • Hi. Why would I need an Arduino if I have a Galileo board? Thanks.

  • Yeah, that’s what Arduino needs… Intel’s tired-ass ISA.

  • I’m guessing that Adafruits neopixels won’t run on it. Their library uses some assembly language incantations.

  • I’m mostly interested in arduino compatible boards for battery/solar powered wireless monitoring outdoors so the first thing I did was plug in an arduino wireless shield with an XBee 900HP radio on board into the Galileo. Picture at http://99.115.132.114/news2.htm It took a day and a half to get it working but, it works well. I was able to integrate the data packet stream coming from my sketch running on the Galileo with my XBee CS3 gateway and web server where I can view the data, just battery voltages at this point. Battery life of 4 AA batteries powering the node was about 3 hours corresponding to about 350mA current draw on average, very high for an arduino board.

    The Galileo fits in an odd place somewhere between low cost Linux computers like pcDuino/Raspberry Pi and arduino boards like Uno and Mega2560. It costs more,and has no graphics output like the Linux machines and uses way too much power to be a battery powered arduino based device. The most interesting feature of Galileo is that it can access openCV functionality from an arduino sketch. The way this functionality is accessed still needs work though. You have to use an arduino-Galileo extention system() call to pass data and run a linux program you have written and compiled on the SD card separately which uses openCV and then read the results back into your arduino sketch using some file manipulation calls that Intel added to their version of the arduino language. fopen(), fget()…etc. If Intel were to create an openCV standard arduino library that would be a very special feature. That plus a camera shield would make a great vision platform which would fully utilize the Gallileo’s Quark processor performance.

    • I am new on Galileo. After load the linux image (big) on SD card, do I have to install Opencv as did in Linux system? Besides, is there any example of using Opencv on Galileo?

  • put DOS on it.

  • It is for sale at MicroCenter for $60 http://www.microcenter.com/product/424730/Galileo_Development_Board

  • Please describe the wifi card and antennas you chose. It seems that the wifi library is only set to work with two official Intel cards from an Intel forum post.

    • Yeah, it does seem like the official distribution only has support for the Intel cards. Another shortcoming. This is the WiFi card I was using, works well and not too expensive. I paired that with our nifty adhesive, u.fl antennas.

    • The pre-built Linux image only works with two wireless cards Intel N 135 or N 6205.

      Any WiFi card that has a Linux driver should work. I personally have installed an Intel N 6235 and it works great. I followed these instructions. http://www.malinov.com/Home/sergey-s-blog/intelgalileo-addingwifi (though I used different antennas)

  • The Galileo looks pretty neat, but I don’t see why it is even comparable to things like the Arduino TRE. Also, what is the price range?

    • The Galileo runs Linux and Arduino code on the same processor. The TRE appears to use two separate processors. Both approaches have advantages and disadvantages.

    • The price seems to be bouncing around a bit. Mouser has had them listed on their website since October. If I recall correctly, when I first saw it the price was about $89. Since I put in my order in early November, I’ve also seen them mentioned at $99. When I looked just now, Mouser was listing them at $66.91 in single unit quantity. At the moment, though, I wouldn’t be confident about the price until I see them actually shipping.


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