Oki, why should I use this Event GSM Dialer?
As the Event Phone Dialer I think that an independent channel (GSM) would be the best solution to inform me when my alarm system recognized a problem in the house during my absence. When an alarm signal has been detected – window / door detector, motion detector, gas detector – the alarm system gives alarm and the ATmega causes the SIM800L to send an SMS to all phone numbers in the address book of the SIM-card.
To realize that you need a box with some nice gadgets inside. Have a look to the schematic of the GSM dialer. You can see the input circuit connected to the alarm system . The optocoupler applys the galvanic isolation to the alarm system’s power side. The heart of the circuit is the ATmega 328P. It controls the following hardware modules:
– GSM-Module SIM800L via software serial line for SMS
– LC-Display via IIC for user information output
– RS232 Interface for managing the SIM-card
The pcb is single-sided and very easy to recreate. Look to the pcb. Another inpresssion gets the 3D-model of the dailer.
The software of the GSM dailer is pretty easy. After startup the ATmega is falling in a power-down sleep mode. Only an interrupt on INT0 means alarm can wakeup the uC. In case of alarm the software reads the phonebook of th SIM card and writes SMS to all of its entries. Be carefull with those entries. Remove default entries from the phonebook and set new one of your mine.
Ok, you need some driver described in the source code. This is the zip file of the complete software written in C++.
Have fun!