Lawn Sprinkler, Mixed Signal Layouts, and New Products


I often get asked what it is we do here at SparkFun. I as of yet, do not have a decent answer. But when projects like Pete's come along, they make a great concrete example. What do you do with a microcontroller? That's easy to answer! We use microcontrollers to solve simple problems.



Pete had a problem. His lawn needed watering but the sprinkler was throwing half the water onto the street and side walk. With an Arduino, a pot, and a servo controlled value, he was able to control where the sprinkler head delivered water. A simple problem with an elegant solution. Nice job Pete!

http://www.sparkfun.com/datasheets/BreakoutBoards/delta-sigma.jpg

We have been playing with high resolution (24-bit) ADCs lately and we came across a great application note written by e2v (if they're making dental x-ray scanners, they must know something). When it comes to mixed mixed signal PCB layouts, proper layout can be tricky. Checkout this great document to find out more about how to layout PCBs to prevent ugly current loops, proper PCB stack-ups, and some notes on proper analog and digital grounding.

http://www.sparkfun.com/tutorial/news/PaulAguayo-M.jpg

MCI Electronics in Chile is our biggest distributor in South America. Paul Aguayo was on vacation with his girlfriend in New York and decided to swing through the SparkFun office in Boulder for a tour and a great exchange of business stories. Paul and I had a great time catching up. I can't wait to return the compliment by traveling to Chile someday.

Always new stuff!


This is a tiny MEMS microphone mounted on a breakout board with 100 gain amplifier.


This is a breakout board for the VS1000D a single-chip Ogg Vorbis (license-free audio codec) player with USB and NAND-FLASH interfaces. This board makes it incredibly easy to add audio to your project. It can be embedded and controlled with just a few GPIO lines! By itself, it is a fully functional Ogg-Vorbis player out-of-the-box. The flash chip has a 256MB capacity, and the board has all the features of a standard audio player. Audio files are added over USB and the playback quality is great! The board can drive headphones or a small speaker with no additional power source.



This is a simple to use USB evaluation board for the GE865-Quad cellular module. All pins of the GE865 are broken out, so you'll have access to the state-of-the-art DAC, ADCs, and GPIOs.



The LPR530AL dual axis gyro has a maximum sensitivity of +/-300 degrees per second and very low power consumption.



This is the micro switch that is used on our concave and convex buttons.



6 pin right angle female header.



Remember the Nintendo Power Glove? This is an awesome project that captures motion using flex sensors, accelerometers, and an Arduino! Great job Noah!

Comments 29 comments

  • On the water sprinkler, this is unreal, I had the exact same idea for a project last week. The catalyst, I have an existing in ground irrigation system that was with my home when I purchased it. In the past month I’ve had to dig into the ground twice, once to fix a cap on the line that blew off and another to fix a head that was jammed and wasn’t popping up. Both times I ended up fiddling with sprinkler heads and nozzles trying to figure out the optimal patterns to cover the most area without wasting water. And after the second problem where 2 hours worth of tweaking got me to about a 70% solution and I need to control the pressure to get that other 30%.
    It would be nice to have an all in one unit that you could program with a 2d profile of your yard (or a given area) at a fixed point and have the sprinkler head rotate and modulate so that the entire area is covered and little more.

    • Hi Chance! Sorry to hear your fiddling was not 100% successful. I’m working on some code and a board that might be more like the “all in one unit” that you’re talking about. It will auto-sync with the sprinkler (via compass), set up 5 windows of sprinkler position, and then allow the user to input the desired water pressure level for each window. You would set each window pressure by turning 5 trim pots linked to ADCs on the micro. Does this sound like a fun product Sparkfun should sell?? Hey Nate, hint, hint! :)

      • Hey Pete! Idea for that all-in-one device:
        If the device also had the ability… somehow… to quantitatively measure the soil’s water content then it could not only water until a certain saturation threshold is achieved but not water if the lawn is already over that threshold, say after a rain storm. The water savings there could be significant and you could fine-tune how much water your lawn gets if you’re a real stickler for conservation. It seems like several physical measurement locations would be necessary and they would probably need to be separate from the sprinkler heads themselves.
        I’m under contract buying my first home right now so in under a month I may have a lawn to call my own. I may want one of these!

    • Yes, props to Pete are in order. Well done!! This has been a fun project for our team as well. Check us out at Innogation.com and if you find yourself in San Antonio, TX during the first week of December, stop by our booth at the Irrigation Show.
      And yes, Sparkfun has been an invaluable resource in the development of the SmartRotor.

      • Hey Thanks! Your site looks cool. Yeah for saving water!! Any chance we could see a video or pictures of the Smart Rotor?

        • Hey Pete,
          The push for the show is complete. Videos are posted in the gallery @innogation.com
          Have a look and drop me a line with your thoughts!
          :) Rob

        • Well it pretty much like looks a regular rotor style sprinkler. Boring on the outside but all the magic is inside.
          I’ll see if I can’t post a video on the site. We’re up to our eyballs preppin for the show so it may be a bit.

  • The last 6 pics above are not showing up and when you click where the pic is, it sends you to the home page?

  • Just curious, which 24 bit ADC’s have y'all been playing with and are there plans for a breakout board or interface?

  • Nice hair.

  • I read the e2v paper and found it very informative. The bit at the very end, though, where it says not to split the analog and digital ground planes lost me. I was following everything up to that point, but that particular leap lost me. Seems like a sentence or two of reasoning was skipped over.
    It sounds like they were suggesting that you would just keep one big ground plane for A & D if you had multiple analog circuits that had to interact with each other as well as interact with the digital side.
    Anybody able to elaborate?
    - Dean

    • I think when they say “do not split the ground plane” at the end, they are telling you not to do something like Figure 2-1. The rest of the figures use a solid ground plane, but with one or more “pinches” that restrict the return paths.

  • Damn it@! I just orderd 10 MEMS microphones, and just to be sure I asked on the IRC channel if there were any breakout boards comming soon… nope, well i guess yeah, 4days later.
    Oh well, keep the MEMS products comming, I love nano stuff.

    • Sorry about that. I do what I can on IRC, but I tend to spend my days locked in combat with PHP and Linux system utilities, so as a rule I don’t have the faintest idea what’s going on with products. We try to get engineers on there once in a while, but they keep making lame excuses about having work to do…

    • Sorry!! Feel free to return the bits if you need the breakouts instead.

  • Nate,
    E2V did the detector array on the main imager of the Hubble:
    http://www.e2v.com/news/e2v-ccd-imaging-sensors-to-enable-nasas-hubble-space-telescope-to-explore-the-nature-and-history-of-our-universe-with-greater-capability-than-ever-before/
    Wow, that was very long (and self-serving) link!
    Sincerely,
    Mark

  • Question on the Mixed Sig article.
    I know it is a factor, but when does it become critical?
    I am getting into Mixed signals a lot lately and so far (knock on wood) haven’t seen an issue.
    The signals I am working with however are low freq, basic Analog DC type signals. So I assume it’s not critical to the signals I have been working with.
    I can see however how the higher the freq the more important it becomes.

  • Nate, dude, you gotta tell us the story about your hair. Working on some high-voltage projects lately?

  • For some reason the front page isn’t loading correctly in Safari for me anymore. The menus in the right hand column aren’t loading at all, and the latest blog post only loads up until “This is a breakout board for the VS1000D” and there is nothing after that.
    I had to open up Firefox in order to post this comment. :/

  • The text of this post has a bunch of rn’s bridging words e.g “playerrnwith”. I can only imagine some mangling of DOS-style newlines (backslash-r backslash-n) by some bad PHP code (I know, redundant).

    • Thanks for the heads up! I think I got them all. Grr. It is a bug in our WYSIWYG. Basically, it’s some \r\n characters with the ‘\’s getting removed.


This Week

This Month

Heartbleed

Happy Arduino Day!