14-03-2017, 12:25 PM
The principle of the DTMF tone signal thus received from any telephone to remotely switch any set of street lights. On roads, street lights stretch over a large area and therefore the operation of these lights is a very heavy and difficult task. Taking into account these problems, the proposed system using DTMF technology has been designed to remotely control street lights.
To accomplish this, a cell phone will send digitized commands to another cell phone that is in auto-answer mode at the receiving end. Receiver cell phone codes are converted into digital commands using a DTMF decoder, will identify the key frequency and convert that frequency into digital codes which will then be fed to a programmable microcontroller of the 8051 family, according to the sent commands of the senders Mobiles The microcontroller will send signals to activate the street lights causing the Relays to light for each command sent by the mobile sender, these relays are driven by a relay controller ULN2003. The power supply consists of a 230 / 12V lowering transformer, which reduces the voltage to 12V AC. This is converted to DC using a Bridge rectifier and then set to + 5V using a 7805 voltage regulator which is required for operation of the microcontroller and other components.