The diploma thesis describes the development and making of a prototype microcontroller system for wireless management and control of various devices via the GSM/GPRS network. The system can control an automatic driveway gate using a phone, a few additional devices, it can display system status, and periodically measure temperature. Communication with the system can be done via the GSM network through calls and text messages, while most of it takes place via the GPRS connection using the MQTT protocol and the Adafruit IO service of the IoT analytics platform.
The core of the device is an 8-bit Atmel microcontroller, which communicates with the Neoway GSM module via an asynchronous bus. The module uses a GSM and a GPRS connection to connect to the network. It is powered by an external DC power source; in the event of a power failure, a lead battery supplies the power. The inputs are additionally protected with external clamping diodes. The relays are controlled via an integrated driver circuit with high current outputs. The temperature sensor communicates with the microcontroller via a 1-Wire bus. All of this is packed into a PVC housing. A minimum number of conventional elements has been used, which helps to reduce the price and the surface area of the printed circuit board. The system’s operation is very cost effective.
The system can be controlled via calls and text messages by no more than five authorized users. System management can be shared with other users via the Adafruit IO dashboard, where user permissions can be set for each individual user.
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