This project would show you how to control an AC appliance remotely from anywhere using your mobile phone. This kind of project is useful in various applications. Say for example a farmer can switch ON or OFF the motor pump present near his field remotely. In this way he need not travel all the way to the field to control it, especially at night times. 

Did you know that most of the thefts at home happen when it is empty? But not everyone is rich enough to hire a security for their house and at the same time they themselves cannot be at home 24 by7. Now what if there is a system which alerts you about an intruder through a text message?The following tutorial teaches how to make you own intruder alerting system 

The sim card interfaces consists of the series of the impedance matching circuits as we see there are six pins and there are eight pins some of the sim’s. The termination resistor has a value of 1- 10k ohm for data line & reset line and here we have 1-2k ohm for the clk line.we here build the circuits as per the pin requirements as we see i have connected the crystal oscillator for the clk pin and the requirement is calculated Vsim pin is connected to the DTR of rs232 terminal, then the clk is to the crystal oscillator,these data lines simdata and Vsim terminalthe the RTS of rs232 is connected to the simrst pin ,the circuit shows almost all the pins covered this is done without using any other ic. The chip is all integrated to the single cable usb line which has max 232 which converts the TTL logic to the computer logic.