This project is interesting to me because its development didn’t stay on the table, but I installed it in the field. This causes many problems that I didn’t know about before.

The device is a comprehensive security system located in a scout hut in the middle of nature. The hut is not connected to the electrical grid and the GSM signal coverage is very weak. Therefore, it was very challenging to design a functional and maintenance-free version. The device includes a simple GSM module Simcom SIM-900, which provides communication through SMS. The device includes two PIR motion sensors, two MQ-xx sensors for detecting carbon monoxide. There are also five 1-Wire temperature sensors in the hut. The device also monitors the voltage of the battery, which is part of the photovoltaic system.

The controlling MCU is ATMEGA8. The MCU ensures regular communication with the GSM, checks the status of all sensors, and evaluates whether the set values have been exceeded. If it detects an exceedance, it quickly performs a control measurement. If the control measurement is the same, it sends a warning SMS to the hut manager via the GSM module.

The hut manager can request all data. They can do this by sending an SMS to the phone number of the SIM card located in the device, in a specified format. The security device will respond to them.

I installed this system in 2015. The system was dismantled after nine years. The photovoltaic system in the cottage was upgraded and Tuya sensors were added. The security system I developed no longer made sense. When dismantled, the system was completely functional.