only someone with a proven experience with SIM800L GSM module specially DTR and RING PINs handling with open drain transistor.
Here's some information about the required and more information will be given after.
- GSM Module
- RTC with Interrupt pin
- Ultrasonic sensor
Consider the following:
- Low power consumption required.
- System powered by solar and lithium battery 3.7V (18650)
- Microcontroller EEPROM used to store configurations like
o Station name.
o Maximum distance.
o Distance measuring.
o Receiver mobile number.
o Checking period (every 12 hours, daily, weekly, every two weeks or monthly).
- Microcontroller and GSM Module running into sleep mode by default.
- RTC responsible to wake up the microcontroller via interrupt pin.
- When Microcontroller wake up will do distance measure by ultrasonic and compare to the stored maximum distance and if more than will wake up the GSM module and send SMS (English and Arabic, SMS will be given later) to the receiver mobile number.
- Configuration will be received by SMS (specific format to be documented for that) during sleep mode and RING pin will be handle the Microcontroller wake up to read the SMS from the GSM Module.