Remote Control Sprinklers: The Irrduino Project

So... I connected my lawn to the internet.



More specifically, I built an internet-based control for the thing that most contributes to the on-going health of my lawn. That is, the sprinklers.

I call this project Irrduino, because at the core of it is an Arduino microcontroller that lets me remotely control the irrigation zones at my house. Irrduino communicates via Ethernet and standard html requests and responses (specifically a REST interface with JSON responses, for you web geeks out there) which means I can control my sprinklers from anywhere on the planet with a web browser and an internet connection, or any smartphone with the same.

Why the heck would I want to do that?

Well, first and foremost, because I can. I wanted to see if I could do it. Beyond that, there are some very practical reasons for wanting to do this, which should be readily understood by anyone who has ever had to do maintenance on sprinklers. They need to be tested regularly, and when you test sprinklers, it’s best to be able to chose exactly where you are standing when the water comes on. So being able to turn them on from my phone is very handy for testing. But that’s not the best part.

The best part, by far, is being across the street at my neighbor’s house and seeing the neighborhood cat preparing to use my lawn as a a toilet, pulling out my phone, pushing a button and watching the feline fur fly.

Hardware

I started with the Android Accessory Development Kit (ADK) as my Arduino platform. In retrospect, this board is massive overkill for the project, but it’s nice to have a extra headroom just in case. I knew early on that I didn’t want to have the ADK plugged into my phone so I invested in an Ethernet Shield so I could connect it to my home network. After it arrived, I spent about a week trying to figure out why it didn’t work, until I discovered that the shield needs to be plugged into the Arduino ISCP header pins, which don’t exist, as such, on the ADK. Luckily those connections can be made separately, and once I figured that out, it was off to the races with a teeny, tiny little web server.

Next, I needed a way to control the higher voltage circuits of the sprinkler value solenoids. Sprinkler systems typically run at 24 volts and somewhere between 700 and 1000 milliamps. After a bit of research on the topic, I figured out the electronic component I needed to control these higher power circuits was called a relay. Being rather new to electronics engineering, I settled on something that was prebuilt and designed to work with Arduino. For that reason, I bought a few of Seeed Studio’s Relay Shields, waited for them to show up, then hooked them up and once again spent another a week trying to figure out why they didn’t work.

Turns out the Relay Shields are a bit power hungry. Running them off the 5-ish volts of USB power that easily runs the ADK and the Ethernet Shield, is not enough to run the Relay Shields. It’s a bit annoying, but easily solved with 9 volt wall adapter plug connected to the ADK, and then connecting the Vin power pin and neighboring ground to a power bus connected to the power inputs for the Relay Shields.

Wiring

After bringing all this hardware together, I started wiring it all up and writing the Arduino control software. The first task (after figuring out that the the shields needed 9 volts of power) was connecting the control wires to the Relay Shields signal inputs. After a quite a bit of experimentation, I settled on using standard Arduino pins 2 though 9 for controlling the first two shields, and pins 11 and 12 for the third shield.

There were a couple of key learnings from the wire-up process:

• Don’t Use Pins 0, 1, 10, 13: These pins receive quite a bit of signalling for other purposes, so don’t try to use these as output controls for the relays. Pin 13 on the ADK, in particular, gets flashed quite a bit when you upload new programs, which I spend a lot of time doing. Once you have a program that you are happy with and don’t need to update, it may be OK to use it.
• NC, NO: What’s that? On the Seeed Studios Relay shield the big, green screw terminals are labeled NC#, COM#, NO#. This stands for Normally Open (NO), common wire (COM) and Normally Closed (NC). For use with a sprinkler system, the control circuits are usually disconnected (Open) and only connected when the sprinkler valves are open, so I used the NO terminals to connect the sprinkler valve circuits.

Software

There are several separate software projects that contribute to the functionality of Irrduino:

• IrrduinoController - This software runs on the ADK / Arduino microcontroller and is the core of the Irrduino project. It runs a small web server, handles the http REST requests, activates and deactivates the relays to turn the sprinkler values on and off.
• IrrduinoRemote - This Android application is what I'm using in the video to activate the IrrduinoController. There is not much to this application, because there doesn't need to be. I wrote the original, functional version in about 3 days.
• IrrduinoServer - This Google App Engine server application acts as a reporting backend and alternative controller it was written in Python by my partner in crime on this project, JJ Behrens.

The IrrduinoController software presents REST-like interface for client applications like the IrrduinoRemote app, the IrrduinoServer, or anyone with a web browser. The software call for turning on a sprinkler valve drives digital output HIGH, thereby activating a relay, closing a circuit for one of the valve pumps and turning on the water. Once you know which sprinkler zone to activate and the digital pin associated with it, all you need to do is call:

// turn on selected zone
digitalWrite(pin, HIGH);

More challenging is receiving and interpreting a REST command to turn on a zone, and running a sprinkler zone for a specified amount of time without blocking the processing thread. Luckily, I had some help and inspiration for interpreting REST commands from Jason Gullickson’s excellent RESTduino project. For the non-blocking timer, the Arduino forums were quite helpful in suggesting setting a end time with the millis() function and running a check function on each loop.

There was a lot of trial and error and rework for the Arduino code, and I’m already planning a major refactor to make extension of the Irrduino code. I’ll let the code speak for itself, with the caveat that it is not particularly elegant but, it works.

Irrduino 2.0

As I was working on this project, it became clear to me that the Irrduino system could easily do more than just remotely activate my sprinklers; it could actually run them, full time, and thus allow me to replace my commercial controller with a completely open source, open hardware solution that would give me way more control and flexibility in how I watered my landscape. I could give it a regular schedule to run, and then give it enough smarts to adjust watering based on seasonal timing, predicted weather, actual rain (rain sensor), or do even smarter things like automatic soak-wait-soak scheduling, water budgeting and more.

For Irrduino 2.0, I plan to add timed scheduling, and after that the sky's the limit.

Arduino Remote Control Irrigation Rig - Prototype 2

Last night I finished Prototype 2 of my Arduino irrigation remote control rig. Added the screw terminal headers so I can connect the irrigation control wires. The very last screw terminal on the right with the white wire is my power bus. It's wired into the COM terminals of all the relay boards.



For those of you who may be wondering, this iteration is mounted on an old IKEA cutting board. I needed the extra physical strength, because the 18 gauge wire used for the irrigation wires is stiff and heavy.

I drilled holes in the cutting board that are just big enough for 4-40 machine screws to poke through (7/32 drill bit, I think). The relay boards have long pins on the bottom, so they need be elevated off the board. I found some 1-inch spacer nuts at Fry's, and that's what the relay boards are mounted on top of. It worked so well, I will be doing the same for the Arduino ADK and Ethernet Shield.

Next step: Wire it up to my irrigation control box and try real hard not the burn the house down. The real trick will be to tap into my irrigation controller's 24-volt power supply without disabling the controller. Fun times!

It Works! Remote Controlled Irrigation via Arduino

Success! I can now remotely turn on my sprinkler zones via my Arduino-powered web server.

The picture does not do justice to the amazing amount of wiring nuts I used to make this work. I think there are nearly a dozen of them holding all the wires together.



I did not manage to hook the Toro controller's 24-volt power supply into my rig. Sharp-eyed readers might be able to spot the two 9V batteries I clipped into my valve control circuits as a temporary power supply.

Anyway, it works! Awesome! Now to write the native Android controller app...

Edit: I have since torn down this setup so that I can mount my Arduino hardware on something a little more substantial (and less flammable) than cardboard. Stay tuned...

Arduino Remote Control Irrigation Rig Update

Last night I tried hooking up my Arduino irrigation remote control rig to all three of the SeeedStudios Relay Shield I bought a while ago. Now here's a nice hack:



I took a piece of cardboard and some unused 1/8 inch rivets, poked the non-rivet end into the cardboard and set the Relay Shield on top of them using the mounting holes. Not a good long term solution, obviously, but it kept the boards from sliding a round while I was wiring everything up.

This project is going to need a much more solid base because the wires for the irrigation system are pretty heavy. I'm thinking about getting a nice, thick sheet of clear acrylic for mounting. I will also have to go find a screw terminal block and use that in between the relay boards and the irrigation wire. Fun! And, I also need to figure out how to get an ethernet connection into my garage where the current irrigation controller lives. Heh.

Arduino Pin Use Limitations: Pin 10, 13

I have a total of 12 relays I can control with the Relay Shields, and I was hoping to use pins 2 to 13 for that purpose. Well, trying that didn't go so well. Apparently the Arduino Ethernet Shield lays claim to pin 10 and so I cannot use it for output. Also, pin 13 (which is connected to the ADK board's LED) gets flashed a lot during program uploads. So, if I connect one of my relays to pin 13, it gets opened and closed dozens of times a second while I'm uploading a new Arduino program. That's going to cause unwanted wear and tear on the relay and possibly overheat it as I noticed when connecting the relays to pin 0 and 1.

So now I'm down to using only 10 relays of my 12. That's more than enough for my project, and if I really need them the ADK lot's more digital outputs. I was hoping to be able to control twelve relays with just the pins available on a Arduino Uno though. Maybe I can use the analog pins to control the relays?

Web Relay Test Arduino Sketch

I wrote this Arduino sketch to test firing the relays on 2 of my Seeed Studio Relay Shields. Shield 1 is connected to digital pins 2 to 5 and Shield #2 is connected to digital pins 6 to 9.

This sketch enables all those pins for output and then turns them on and off for half a second (500 milliseconds) in sequence.

#include <SPI.h>
#include <Ethernet.h>


byte mac[] = { 0x90, 0xA2, 0xDA, 0x00, 0x50, 0xA0 };    //physical mac address
byte ip[] = { 192, 168, 1, 177 };   // ip in lan
byte gateway[] = { 192, 168, 1, 1 };   // internet access via router
byte subnet[] = { 255, 255, 255, 0 };                   //subnet mask
Server server(80);                                      //server port
byte sampledata=50;            //some sample data - outputs 2 (ascii = 50 DEC)            

String readString = String(30); //string for fetching data from address

void setup(){
//start Ethernet
Ethernet.begin(mac, ip, gateway, subnet);

//Set pins 2 through 9 to output
for (int i = 2; i <= 9; i++){
  pinMode(i, OUTPUT);  
}

//enable serial data print  
  Serial.begin(9600);
}
void loop(){
// Create a client connection
Client client = server.available();
  if (client) {
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        //read char by char HTTP request
        if (readString.length() < 30) {
          //store characters to string
          readString.concat(c);
        }  
        //output chars to serial port
        Serial.print(c);
        //if HTTP request has ended
        if (c == '\n') {
          if(readString.indexOf("test=all") > -1) {

httpReply(client);

// cycle through pins 2 to 9
for (int i = 2; i <= 9; i++){
               Serial.print("Writing pin ");
               Serial.print(i);
               Serial.println(" HIGH");
               digitalWrite(i, HIGH);    // set the LED on
               delay(500);
               Serial.print("Writing pin ");
               Serial.print(i);
               Serial.println(" LOW");
               digitalWrite(i, LOW);
               delay(500);
             }
          }
          //clearing string for next read
          readString="";
          //stopping client
          client.stop();
        }
      }
    }
  }
}

void httpReply(Client client){
  client.println("HTTP/1.1 200 OK");
  client.println("Content-Type: text/html");
  client.println();
  client.println("{\"status\" : \"executing\" , \"cmd\" : \"test=all\"}");
  client.stop();
}

This code is loosely derived from code by Mareika Giacobbi of nerdydog.it for his Domotic Home project.

ADK + Ethernet Shield + 2 Relay Shields = Almost Working Prototype

Here is the current iteration of my Arduino Irrigation Controller rig:

I now have 2 of the 3 Relay Shields connected to the ADK with Ethernet. Did I say connected? It's a bit fragile to say the least. Don't breathe on it! Those green wires going into the middle of the Relay PCBs are basically held their by the tension of the wires wanting to straighten out.

I really wish the Seeeduino guys had put on those extra long headers and pins on these Relay Shields like on the Arduino Ethernet Shield. It's basically impossible to attach them to the Arduino board or the Ethernet Shield because these huge freakin' pins from the screw terminals extend 2mm out the bottom of the board (and cause shorts against tall components, if you're not careful).

Now I'm waiting on some parts from AdaFruit so I can connect the 3rd Relay Shield and create a more reliable connections to the first two boards. But, where am I going to put Relay Shield #3? Hmmm...

One other thing that confuses/frustrated me with the Relay Shields is that they cannot run off USB power (5v), you have to plug them into their own 9v power supply, or plug the Arduino into a 9v+ power supply and route the Arduino's 9v pin (not the 5v pin) and ground to the Relay Shields. That's a bit annoying. The important thing, though, is that it works. On to the next stage.

Pin 0 and 1: Don't Use for Output!

Oh, and one other thing: If you are thinking of using digital pin 1 and pin 2 to control the Relay Shields: Don't. I tried using them in an earlier version of this prototype and saw some worrying behavior. Namely, when uploading a sketch to the Arduino board, pins 1 and 2 flash on and off very quickly which turns on the connected relays on and off very quickly and makes them rather hot. I didn't have a catastrophic failure; the relays still work, but that'll be the last time I try using pin 1 and 2 for anything other than TX and RX.

ADK / Ethernet Shield Problem Solved!

Fixed! A quick trip to Radio Shack for some hookup wire (22 gauge, solid) and I manually wired the ICSP pins from the Ethernet Shield and now I have a web server that's just a bit bigger than a deck of cards.



Here is the ISCP pin mapping to the ADK pins for future reference:

(MISO)  50 <--  1 o  o 2 --> +5V
(SOCK)  52 <--  3 o  o 4 --> 51 (MOSI)
RESET      <--  5 o  o 6 --> GND

Only pins 1,3 and 5 need to be connected (orange wires in the picture). The Ethernet shield still works if you leave pins 2, 5 and 6 disconnected (red, yellow and green wires in picture).

Android ADK and Arduino Ethernet Shield Woes

I think I figured out why my Arduino Ethernet shield won't play nicely with my Android ADK Arduino board.

You see the black, six-pin header connector on the right side of the blue board (the Ethernet Shield)? That's the the ICSP bus in Arduino-speak. That's supposed to connect into a matching set of pins on the white Arduino board so the Ethernet shield can to its "talkin' to the interweb" thing. Do you see matching pins on the ADK board? Yeah, neither do I.



Turns out this is a bit of a problem, because the Arduino Ethernet Shield documentation states:

Arduino communicates with both the W5100 and SD card using the SPI bus (through the ICSP header).

Like I said, bit of a problem. Looks like there are exposed copper pads on the bottom of the ADK board for the ICSP connections, so I could solder in some connections if absolutely necessary. Those pads (MISO1, MOSI1, SOCK1) are clearly wired to 50,51 and 52 as described in the Arduino Mega 2560 schematics.

Time for some hand wiring...

Let the Arduino Hacking Begin!

I have jumped into Arduino hardware hacking and bought some shields to use with the ADK I got from work. The idea is to use these to remotely control my irrigation system at home.