electronic lock sms
Using AT commands is easier.
U can add some kind of musical buzzers for audio indication.
Audio indication enables u 2 know if the message u hav sent is received or not.
Added after 55 minutes:
Interfacing with mobiles may be bit confusing for you
Because you don't know what commands it supports
u can use GSM/GPRS modems for ur application
These modems support AT commands
The manufacturer of these modems provide user manual which u can go through n
use d specific commands.
n moreover if u want a housing for your product it would be better to use modems
because u can integrate these modems onto same pcb as microcontroller.
using mobiles makes ur circuit looks bulky n special cables have to be purchased.
u can use TELTRONIKA TM2 Module
or a low cost SIM300/SIM340 modules
Added after 8 minutes:
https://www.hobbyprojects.com/quick...its/automatic_door_opener_with_PIC12C508.html
check out the above link.
It may be helpful for u in designing your relay circuit.