Control via the GSM using the text message service SMS has recently achieved encouraging results in many computerized and mobile applications. Home temperature control is an example of such applications, which necessitates implementation of devices to control appliances like air-condition, heater or performing cyclic sensing for room temperature evaluation.
These sensing and controlling functions are usually performed with a computer interface system while the communication between the mobile phone and the PC is utilized using simple software. The proposed system is shown in the diagram where a Siemens C45 mobile phone is used as the means of communication over the GSM. A Visual Basic software program is written to enable the PC to send and receive SMS messages through the mobile equipment providing AT commands for opening serial port connection.
Chapter – 1 History