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Imagine you have a farm, a greenhouse or a garden which is far away from where you live. You have to travel a long distance everyday to supervise it's environmental conditions like temperature and humidity or to control it's irrigation. So I built this system in which you can do all these using your phone.

 

You can send an sms and request the device to report the conditions or you can control your irrigation system by sending a message to the device to turn your pump on or off.

The device has the capability of executing any irrigation program it's been given. It can control everything automatically and report the result by sending messages or it can be controlled by receiving messages from user. I've also added extra capabilities to enable the system to execute different irrigation programs for different seasons of the year.

I built this system for Ab Yaran Sahand company which designs irrigation systems. We presented the system in the 14th Fair for Industrial and Agricultural Automation in Tabriz and it was well received.

Ok let's go a little bit into the details. The system is built around SIM900 module which is a product of Simcom. This module can be connected to a simcard and it's functions are controlled by a set of commands called AT Commands. Information about the hardware design of the module is here. An Atmel ATMEGA32 microcontroller is used to send commands to SIM900 via USART and to execute the irrigation programs. It also controls the keypad and the LCD.

User can turn on or off the desired outputs using keypad. the keypad command are in the form of "*...#". For example if user enters "*a#" the "a" output will change state.   

User can also check the remaining credit in the simcard using keypad.

The device is programmed so that it only executes the commands coming from predefined phone numbers to prevent misuse.

To send a command to the system using sms is easy. You only have to write "aON" and send it to the device to turn on the first output relay or "aOFF" to turn it off.

This is a photo of me presenting the device in the fair:

SC10_Fair

 As you can see we connected it's output to a powerful contactor (the box on the right) to control a pump on site to show the device's capabilities.

 One of the most important points in such projects is energy considerations. An irrigation pump may only work for one hour everyday. But the control system is on 24 hours. You have to design the system so that it consumes very low power although it's working. I noticed these issues and programmed the microcontroller to go into idle mode when it's not controlling anything and is waiting for an sms to arrive. I also put SIM900 in sleep mode during waiting times to minimize the power it consumes.

These design considerations make it possible to use rechargeable batteries to power the device and so when the electricity goes off it can send an sms to the user to inform him/her.

 

   
  
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