Thanks for ur reply.
i get the info abt the touch switch.
but how can i make the touch switch to be attached with the lock so that the whole component acts as a touch sensitive device. if an intruder touches his hand or key on the lock then the touch switch should transfer the signal to the SIM 300 modem. also do i have to keep an arduino board inbetween the touch switch and the modem so that the signal gets transferred to the modem correctly?