The concept of tone DTMF (dual tone multi frequency) tone command received from any telephone to remotely switch any electric load such as agricultural pump, domestic and industrial loads, etc. In industries, loads extend over a large area and so Therefore, the operation of these Loads is a very heavy and difficult task.
In agricultural fields too, pumps and other loads are connected in a large area and, therefore, it is difficult for the farmer to operate all loads and similarly for maintenance loads of the house. With these problems in mind, the proposed system using DTMF technology has been designed to control loads remotely.
A cell phone is interconnected to a DTMF decoder in the system from its audio output socket to receive tone commands. Receive cell phone codes are converted into digital commands using a DTMF decoder that will identify the frequency of the key and convert that frequency to its equivalent digital code that will be fed to a microcontroller (8051 family).
Depending on the commands sent from the sender's mobile, the microcontroller will send signals through a buffer to trigger the respective loads by turning the relays on / off. These relays are driven by an IC relay controller connected to the microcontroller. In addition, this project can be improved by using a GSM modem, where loads can be controlled by sending an SMS. This will eliminate the need to answer the call for the system to work.
It can be understood in the following video: