The project HOMEControl should ultimately result in a complex WLAN-based smart home system. Here are some features of this system:
- Inexpensive and powerful controllers from Espressif
- Completely WLAN supports no cabling
- Energy-saving sensors for battery operation
- Independent subsystems
- No internet access required
- Can be expanded as required
- Easy to program
The core of the system is an ESP32, which is ideally suited for this with its performance and memory equipment. The cheaper ESP8266 controllers can be used for the slaves.
A WPA-protected network is used to ensure high security against external access. Each slave must be manually registered with the master once. With this registration procedure, the slave receives the necessary access information for the secured WLAN and the master receives the unique serial number of the ESP8266 on the slave. With every further communication only data from known slaves (serial number) are accepted. The master receives measured values from sensors. Depending on the programmable conditions, the master will evaluate the values of the sensors and output appropriate signals to the actuators.
For data exchange it is then irrelevant how the measured values are read from sensors and possibly converted or how a transmitted output value in the actuator is converted into a corresponding action. It is therefore very easy to design sensors and actuators and connect them to the system. Appropriate libraries will be available for communication with headquarters.
Self-sufficient subsystems can be formed via sub-centers that are themselves connected as slaves to the main center. The sub-control center can access the measured values of its own sensors, but also those of the main control center, and use these to derive the conditions for activating its actuators. The sub-control center is registered with the main control center and transfers all measured values of its sensors to the main control center. In the simplest case, a sub-control center is a single controller to which sensors and actuators are directly connected so that it does not need its own WLAN.
The system is primarily configured and programmed via USB from a PC. It is also planned to enable the configuration of the smart phone via blue tooth. A display and corresponding input devices are available at the control center for simple status queries and the registration of a slave. The head office will also receive an SD card reader, which can be used to read in particular lists of conditions. The SD card will also be used for an extensive log of all actions in the system.
It is also planned to provide secure access from the main headquarters to the Internet so that the status of the system can be called up from anywhere. Depending on the permissions, certain actions should also be enabled from the Internet. Since there is only a single connection to the Internet in the entire system, the highest possible level of security can be achieved.
The series of instructions will begin with the presentation of the hardware for the control center.