Apr 30th, 2014 by ray
Last week I wrote a short story on OpenSprinkler for the Make Magazine blog. It’s about how learning Arduino inspired me to invent the OpenSprinkler. Check out the blog post at the link below:
Thanks to everyone who helped and contributed to this project!
This year we will be having a booth at the Bay Area Maker Faire again. If you are going there too, make sure to drop by our booth and check out OpenSprinkler, SquareWear, AASaver, and the upcoming goodies. Thanks!
Apr 15th, 2014 by ray
A new day, a new post. Today’s post is about the new OpenSprinkler Zone Expansion Board v2.0, with injection-molded enclosure and 16-station capability. The injection-molded enclosure provides a coherent look with the OpenSprinkler main controller; and the 16-station capability adds twice as many stations as before, without taking extra space.
As I briefly talked about in a previous post, this new version 2.0 is only slightly larger than the previous version 1.1, but can handle twice as many stations. You can think of it as basically two 1.1 boards (8 stations) squeezed together onto a single board that’s roughly the same size as before. What made this possible is a clever design that makes use of the same four support pillars to both attach the top and bottom pieces together, as well as secure the PCB inside the enclosure. This saves some space normally reserved for the PCB screws. The design was proposed by Xavier at SeeedStudio — the principal industrial designer for the project — and it follows the same design adopted for the OpenSprinkler enclosure.
Also, version 2.0 has included per-station bidirectional transient voltage suppressor (TVS) for added electric protection. These are essentially diodes can clamp the voltage if it exceeds a threshold in either direction. This can reduce the chance that a high transient voltage or lightening damages the circuit or the sprinkler solenoid.
In terms of usage, version 2.0 is the same as 1.1. It works for all of OpenSprinkler, OSPi and OSBo. Use the 2×4 extension cable to link the OUT port of the main controller to the IN port of the expansion board. Additional expansion boards can be daisy-chained in the same way — by following the OUT -> IN links. Because 2.0 and 1.1 have the same cable wiring, they can be mixed and used together.
The firmware currently does not automatically detect the number of stations. So you need to keep in mind that each 2.0 counts as 2 expansion boards (2x 8) in the option settings.
Because of the difficulty in stocking both versions, we have discontinued 1.1 and are only offering 2.0 now. Price-wise, it is a little more expensive than 1.1. So if you only need 8 extra stations, sorry, you have to pay the extra to get 2.0. But if you need a larger number of extra stations, this is a great deal because it’s considerably cheaper and saves a lot of space too.
OpenSprinkler Zone Expansion Board v2.0 is available for purchase at the Rayshobby Shop. We offer bundled discount if you are buying it together with any OpenSprinkler main controller, including OpenSprinkler v2.1s, DIY v2.1u, OSPi and OSBo. Be sure to check the “Add Zone Expansion Board Options” when you purchase. Thank you!
Apr 13th, 2014 by ray
I am very excited to announce that the OpenSprinkler native mobile app is now available on all platforms (iOS, Android, Windows Mobile). A big shout-out to Samer Albahra for his diligent and absolutely fantastic work in developing this app!
Different from the previous OpenSprinkler web app, the native app can be installed as a standard app on your mobile device. This not only enables some new features (such as automatic scanning device, multi-language support) right away, but opens doors for more exciting features in the future, such as push notification and local storage (e.g. representing each station with a photo icon). The app is free, so go ahead and give it a try right now!
Let me briely go through the requirements for using the app:
NOTE to keep in mind: the app provides an alternative front end to the OpenSprinkler controller. The default front end, which is the controllers webpage (accessed by typing in the controllers IP in a browser), is still available and functioning. Any operation you apply through the app will also be reflected in the default front end.
The app has a number of notable new features:
These are just some of the highlights I would like to bring to your attention. There are plenty of other features that really make the app stand out, such as automatic count-down timer, easy editing of station names and programs, intuitive program preview, instant launch of any existing program (not just the run-once program), import/export configurations. You’ve got to try it out yourself to find out.
To find out additional details, please go to Samer’s website. Discussions of ongoing development are available at the Rayshobby Forum. Samer is continuously supporting the app development. Please kindly leave your comments and suggestions, either in the comments section below, or on the forum. Thanks!
Apr 6th, 2014 by ray
Curious what the next version of OpenSprinkler Pi (OSPi) is going to look like? Here is a sneakpeak preview of version 1.4:
Wait a minute, what is this strange looking board?! And the Pi is installed at an angle? What’s happening here? Well, the new design is all centered around one simple goal: to fit OSPi and RPi into the existing OpenSprinkler injection-molded enclosure. There are many good reasons to do so. The first is cost reduction: the current OSPi uses the Serpac WM032 enclosure with custom cutouts. This is quite expensive to make. On the other hand, the microcontroller-based OpenSprinkler already has an injection-molded enclosure (and I paid a good amount of money for the mold!), so it makes sense to consolidate the design to use the same enclosure. This will bring down the cost quite a bit. Using the same enclosure also gives both products a consistent look. In fact, in the near future OpenSprinkler Beagle will also adopt the same enclosure, and hence all three will have the same exterior look.
The ‘why’ part is easy to explain. But the ‘how’ part proves to a non-trivial engineering challenge. When I was first fiddling with the idea I didn’t think it was at all possible. After all, the injection-molded enclosure was made before OSPi came into place, naturally it was not designed with RPi in mind. It turns out that, due to the positions of the support pillars, the enclosure is just a little bit too narrow to fit RPi at a straight angle. Ouch! But after staring at it for a while like a geometric puzzle, I was delighted to find out that if you rotate RPi by 3 to 4 degrees, it fits perfectly! This gave me inspiration to further develop the idea. It also explains why the Pi has to be installed at an angle, as the picture at the top shows.
In fact, by carefully positioning the Pi, the Ethernet cable can also fit, albeit through the USB cutout instead of the RJ45 cutout. It’s a bit tricky to figure out the position precisely, but I am glad that after two rounds of prototypes I finally got it right 🙂
Of course since OSPi doesn’t have buttons and LCD, some of the cutouts are useless. I am not completely sure what to do with the LCD cutout. If I leave it alone, it looks quite ugly (see picture on the left below). So my temporary solution is to just put a sticky label at the back, thus covering the big empty hole (see picture on the right below). Eventually I think it’s best to put some graphic design here. I am undecided what to put here. It shouldn’t be the OpenSprinkler logo as the enclosure already has a printed logo. If you have suggestions, please leave them in the comments section. I would greatly appreciate it!
Next, because the injection-molded enclosure is not high enough, I cannot continue using the current design where the Pi faces up and connects to OSPi through ribbon cables. It’s necessary to flip the Pi and plug it into OSPi facing down. This will reduce the height of the overall assembly. However, there is one additional complication: the USB, Ethernet, and composite video connectors on the Pi are all quite tall, so it’s necessary to make cutouts on the OSPi PCB to allow these connectors to sink below the board. The picture on the left below shows the back of the PCB, and you can see where the connectors go through the board.
As the Pi is now facing down, it’s not easy to access the GPIO pins directly. Therefore I’ve mapped out all the 2×13 pins on the Pi to the pinout area, seen at the top-left corner of the PCB.
The last bit of the puzzle is the SD card. Since the enclosure has very limited space, it’s not possible to fit a full-size SD card, without making a cutout on the side. So we need a low-profile SD card. There are several options, one is this microSD to SD adapter. It’s basically a microSD card slot soldered onto a PCB shaped like an SD card but half the size. This and other similar adapters are readily available online and they work reasonably well.
While Googling ‘low-profile SD card’, I found an surprising solution that’s dead simple. In case you don’t know this already: many full-size SD cards are actually half empty. What this means is that the useful stuff (namely the chip and connectors) only take half the space, while the other half has nothing in it! As a result, you can safely cut half of the card away, thus making a low-profile SD card without any adapter. This also has the advantage of preserving the high performance of a full-size SD card (while the microSD card is considerably slower). The downside though, is that if you ever need to insert the SD card to your computer’s SD card slot, you will have to tape the other half back, so that it extends to the original length. Otherwise it will be too short to push in and pop out.
Anyways, this is the end of the story. I admit the new funky design feels a bit forced: it’s born out of the need to re-use the injection-molded enclosure, which wasn’t designed with OSPi in mind. But I am quite excited that I figured out all the pieces of the puzzle. Eventually I may pay a sizable chunk of money to order a new mold dedicated to OSPi, but before that happens we have to stick with the existing resources 🙂
The hardware components remain largely the same with version 1.3. The only difference is that the relay has been upgraded to a slightly bigger, 250V / 3A type. I am also considering adding a pin header for the nRF24L01 transceiver, to make it possible to communicate with our upcoming products such as OpenSprinkler Bee. Pending a few minor tweaks, things should be finalized within a month or two. Please leave your comments and suggestions, as this will be the last chance to influence the final design of 1.4. Thanks!
Mar 27th, 2014 by ray
Update: check out our new standalone OpenSprinkler Bee (OSBee) 2.0 with built-in WiFi and OLED display.
It has been a month since my last post. Apologies for being silent for a month. In the meantime a lot of new exciting projects are happening. Today I am going to show you the first prototype of OpenSprinkler Bee (OSBee) — a programmable sprinkler timer for battery-operated valves.
Like the classic OpenSprinkler, OSBee is an open-source Arduino-based sprinkler timer. The main difference is that OSBee is designed to work with battery-operated sprinkler valves. It’s powered by two AA batteries. In contrast, the classic OpenSprinkler is powered by 24V AC wall adapters. Also, OSBee does not have built-in Ethernet interface, but it has a 2.4G RF transceiver (nRF24L01) and I am considering leaving spaces to add additional modules such as XBee and Bluetooth. This way OSBee can communicate with a base station or a smart phone, for creating web or smartphone-based user interface.
The name ‘Bee’ comes from the abbreviation Battery-Enabled Extension. It’s co-incidence that it sounded more like XBee. It may very well have an XBee slot in the end, but the name was not intended to imply XBee. Also, ‘Bee’ reminds me of the garden, and gardens need to be watered, so, there is the connection. Different from the classic OpenSprinkler, OSBee now comes with a water-proof enclosure, which means it can be left outdoors, such as in a garden, and will do its work diligently, like a Bee 🙂
The history of OpenSprinkler Bee traces all the way back to my very first Arduino-based sprinkler timer project — the Minty Water Valve Controller. It is a wireless sprinkler timer that is small enough to fit inside a mint tin. That was summer 2010 and I was shopping for a sprinkler controller for my new installed lawn. I was starting to learn about Arduino and had this great inspiration to design and make my own sprinkler controller using an Arduino 🙂 There I made it, and I posted a video about it (see below).
It was soon spotted by Chris Anderson, currently the CEO of 3D Robotics. We then started collaborating on the OpenSprinkler project. After some market research, we figured out that most common household sprinkler systems (particularly underground sprinkler systems) use the 24V AC sprinkler valves. That’s why instead of focusing on battery-operated valves, we started designing the classic OpenSprinkler for 24V AC valves. But battery-operated sprinkler valves are also very useful — they are power-efficient, most of them can be hooked up with garden hoses so they are very mobile — you can move them anywhere you have watering need. So far forward four years to now, after releasing the classic OpenSprinkler and its variants OSPi and OSBo, I’ve finally decided to finish up what I started a long time ago, that is, the OSBee!
For the technical minded, here are some details about the prototype design:
One tricky part with preserving the water-proof design is how to make the connection from the controller to the sprinkler valve. To lower the cost, I have to stick with off-the-shelf enclosures, which means minimal customization. The current solution I figured is to simply drill two small holes and insert two wires through the holes. Then you can seal the holes with some hot glue or water-proof spray. Not the most elegant solution, but simple.
Also, the choice of AA batteries (as opposed to rechargeable Lithium batteries) is due to the consideration that the controller may be left outdoor during hot summer days. In this case the temperature can potentially rise up to 60 degrees Celsius, which is very unhealthy to Lithium batteries.
So there you go, the first prototype of OpenSprinkler Bee. I am in the process of finalizing the design. Comments and suggestions are much appreciated!
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