Introduction: Sprinkler Watering System Timer
This is essentially fancy timer(s) with a manual override, intended to run an 8 zone reticulated watering system, programmable via a web interface.
Step 1: Ingrediants
I live in Bunbury, Western Australia, your parts suppliers may differ.
A > 1 Amp, 5 V Power Supply for Raspberry Pi, & USB cable to suit.
I used a Raspberry Pi, Model 2 B, but it is overkill for what is needed.
Micro SD card with Raspberrian on it.
40 pin cable to go from Pi to prototyping board.
40 pin socket to mount on prototyping board for cable to Pi. Search eBay for “2.54mm Pitch 40P Double Rows Straight IDC Pin Headers"
Prototyping board. Search Ebay for “DIY Prototype Paper PCB Universal Experiment Matrix Circuit Board 5x7cm”
Do not go smaller than 5cm x 7cm, the 40 pin header takes almost all of the 7cm length.
3.3 Vdc to 5Vdc Logic level converter x 2 or 3...Search Ebay for “4-Channels Logic Level Converter Bi-Directional Shifter Module 3.3V-5V”
Jumper cable from prototyping board to relay board.. Search eBay for “Female to Male 20cm 2.54mm 1P-1P Jumper Wire Cable for Arduino”
8 Channel 5v Relay board. Search eBay for “5V Relay Module Board”
Possibly a Tempreture and humidity sensor, and 3 Poles/3 Pin 2.54mm/0.1" PCB Universal Screw Terminal Block Connector to connect a rain sensor.
Possibly a Rain sensor of some sort.
Terminal strip to connect field wiring to. Search eBay for “Terminal Block”
24Vac Transformer. I got mine from Jaycar.
Inline fuse holder + 1 Amp fuse from Jaycar.
Double power point + mounting block from Bunnings.
El Cheapo toolbox from Bunnings. Mine cost $22, cheaper than a flat bit of sheetmetal.
If you want to get flash, buy a sheet of flat sheetmetal, and use it as a gear plate to avoid a lot of holes in the bottom of the tool box.
20mm gland to hold power cord flex.
Power cord flex and plug. Avoid anything marked “Infinaty”, they just had a massive cable recall.
A short bit of earth wire and utilux 5mm washer type lug to earth both the toolbox and the transformer.
40mm male & female bush, or a 40mm conduit fitting, so that incoming cables do not touch and rub on the edge of the hole in the tool box.
Depending on your home network setup, a 5 port ethernet hub, and eithernet cable, and a bracket to hold it in the toolbox.
M5 Screws, nuts and washers to hold down the transformer, the power point mounting block.
M2 or M3 Screws nuts and washers to hold down the Pi, the prototype board and the relay board.
A little bit of small retic hose to space the boards off the bottom of the tool box, or possibly some stand off spacers.
Cable to run from controller to soliniods.
Single entry 20mm conduit J box, from Bunnings, one at each solenoid cluster, to connect the solenoids to the wire.
Connectors, or “Blue points” or terminal strip, to join the soliniods to the cable.
6mm spriral wrap, from an automotive shop, to keep the soliniod cables together.
Soliniods themselves. Search ebay for “Irritrol 205MT Flow Control Solenoid Valve”
You can work out your own plumbing and what you might need.
Step 2: Setting Up the Raspberry Pi
Unfortunately the file upload system on this site is broken at the moment, I will add the rest of the files when I can.
In the short term I have placed them at this link..
You might need to install “openssh-client” on your main computer, or something similar so that you can talk to the Pi.
I used the default Raspian Linux distribution, but I would think the differences to any other Linux distribution would be minimal.
Configure Pi to have a static network address. These instructions seem to be as good as any..
I used 192.168.1.100, but this is very flexible and depends on your home network setup.
Cycle power to the pi to make sure the pi boots up to the right IP address.
Put all the included files into one directory on your main computer, then using a terminal, ( I am running KDE within Kubuntu, and used Konsole), change to the directory, where you unpacked the files, then check you are in the right directory by typing ...
$ ls -l ( lower case L )
This should give you a list of files to be transferred to the pi. Then type..
$ scp *.* firstname.lastname@example.org:/var/www/html
The default password is “raspberry”
This will copy all the files in the currant directory to the pi's web publishing directory.
Preferably in a new tab, ( File->New Tab ) type in..
$ ssh email@example.com
This should give you a shell prompt from your pi.
Change to the web publishing directory..
$ cd /var/www/html
$ ls -l
again to make sure the files are in the right place.
You will need to make all the python scripts executable...
$ chmod +x *.py
If this does not work you can either try..
$ sudo chmod +x *.py
or drop back one directory
$ cd ..
And change permissions on the “html” directory
$ sudo chmod 777 html
This second option is not recommended if the pi will be accessible from the Internet.
Update the list of available software...
$ sudo apt-get update
And we may as well do an upgrade while we are at it..
$ sudo apt-get upgrade
Install a web server and support files...
Apache is not the only choice, and is a bit bigger and possibly slower than other options, but it is very mature and has lots of support and options.
The Sqlite3 database is simple and straightforward, just what I want.
$ sudo apt-get install apache2
$ sudo apt-get install php5
$ sudo apt-get install sqlite3
$ sudo apt-get install python
$ sudo apt-get install python-pysqlite2
I am not sure if all of these are all needed, but this is what I used.
$ sudo apt-get install php5-sqlite
$ sudo apt-get install php-db
$ sudo apt-get install php-gettext
$ sudo apt-get install wwwconfig-common
You might also like to install adminer
I did not get it to work for me, but did not try very hard.
$ sudo apt-get install adminer
Follow these instructions to install the wiring pi library.
You should already be at the html directory, if not, change directories..
$ cd /var/www/html
We also need to setup the database. Only type in text after the $ prompt.
pi@retic:/var/www/html$ sqlite3 default.db
Now we need to create a database table to hold the turning on times...
sqlite> CREATE TABLE table_time ( pk NTEGER PRIMARY KEY,
And possibly add an entry or two...
sqlite> INSERT INTO table_time (zone, day, hour, min, seconds) VALUES(1,0,6,1,6);
INSERT INTO table_time (zone, day, hour, min, seconds) VALUES (2, 0, 6, 2, 12);
select * from table_time;
And a second table to keep track of monthly time adjustments...
sqlite> CREATE TABLE table_month (
month SMALLINT PRIMARY KEY,
and prefill it with data...
sqlite> INSERT INTO table_month (month, percent) VALUES (1, 130);
INSERT INTO table_month (month, percent) VALUES (2, 120);
INSERT INTO table_month (month, percent) VALUES (3, 110);
INSERT INTO table_month (month, percent) VALUES (4, 100);
INSERT INTO table_month (month, percent) VALUES (5, 90);
INSERT INTO table_month (month, percent) VALUES (6, 80);
INSERT INTO table_month (month, percent) VALUES (7, 70);
INSERT INTO table_month (month, percent) VALUES (8, 80);
INSERT INTO table_month (month, percent) VALUES (9, 90);
INSERT INTO table_month (month, percent) VALUES (10, 100);
INSERT INTO table_month (month, percent) VALUES (11, 110);
INSERT INTO table_month (month, percent) VALUES (12, 120);
select * from table_month;
You can inspect the tables if you like..
shows the table structure.
If you think you stuffed up for any reason you can always drop a table and start again..
sqlite> drop table table_time;
and to quit from sqlite type...
To run “/var/www/html/water.py” on startup I created “666start.sh” which needs to go in “/etc/init.d/”
To make it executable...
$ sudo chmod +x *.sh
Then move it...
$ sudo mv 666start.sh /etc/init.d/
Ideally it would be started last, but I do not know how to change the order and it seems to work as it is anyway.
At this point in time you should be able to point a browser, on a computer connected to the local network, at your pi's IP address and see a bunch of buttons ready to turn the outputs on and off.
If you click on the “Auto” button you should be able to change the times each zone turns on and runs for. http://192.168.1.100/index.php or just 192.168.1.100
You need to remove the original “index.html” file in /var/www/html for this to work.
pi@retic:/var/www/html $ rm index.html
Hopefully the system time is the same as your local time, if not you may need to change the Pi time zone. This can be done via raspi-config as shown on this web page...
Step 3: Build the Interface Board.
Next we need to interface a 40 pin header from the Pi to a 10 pin relay board, and change the 3.3v signal from the Pi to the 5v that the relay board needs.
The quality of the prototype PCB I used is not that great, the plating is only on one side of the board, but it is good enough. Do not go smaller than 5cm x 7cm, the 40 pin header takes almost all of the 7cm length.
The pinout of the Pi header can be found in a few places including here...
And the pinouts of the relay board and interface voltage adapters can be found on the overlays..
Run links between the 40 pin header and the voltage adapters and the relay pin pin interface point.
I used a couple of jumpers for the longer runs, but mostly I used a single stand of copper wire stripped from the same cable running to the solenoids. You might be able to avoid jumper cables if you had double sided board.
I cut a 20cm female to female rainbow ribbon cable in half, and soldered one end to the interface board, but in hindsight it may have been better to use male to female ribbon cable, and solder the male end to the interface board. 10cm is ample.
I only used one side of the 40 pin header, which is why all my pin numbers are even.
In hindsight a bigger interface board would have been better, with provision for a rain sensor input and / or an IC2 temperature / humidity sensor.
By pure luck I needed 8 zones, which worked in nicely with the relay board and the voltage interface, but it should be easy to increase or decrease this number.
Step 4: 24Vac Soliniods
The 24vAC side of the controller should be simple enough, my setup included 3 banks of solenoids, so even using 2 wires as the return I still only needed 6 neutral terminals.
Step 5: Other Notes.
The manual web control is independent from the timers, except that there is a watchdog timer in water.py that turns the water off after 60 minutes. Just in case you forget to turn it off.
You can toggle a pin directly by pointing your browser at gpio.php?pin=12 , and it will return a list of what pins are on.
The database stores seconds run time, but the web interface shows time in minutes.
The included programs spend 99% ish of their time asleep, with a new thread being started each time the water.py program starts a new timer, so you can have one or all of them on at the same time, and still count the correct seconds.
With no outputs on, my Pi draws 0.2 amps @ 5 volts, but with all 8 relays on it draws 0.83 amps @ 5 v.
I could not find a reference to the maximum currant the Pi can draw, but as my water pressure tends to dip when a solenoid comes on I only have one solenoid on at a time anyway.