In my thesis I developed an architecture, which can be used to control the environmental properties of a greenhouse. This consists of a base and several peripheral devices. The base device communicates with the peripheral devices, with the users, and with the computer. And the peripheral device controls the work of the sensors and actuators.
The base device is attached with the peripheral devices via radio waves. During the communication the base sends commands to the peripherals, and receives their measured parameters. The user can control the system operation with the menu of the base device, and he can set and query the values of the environmental properties. This also can be made with the use of the interface to the computer. The base also manages the time and the date of the system.
The peripheral device measures and controls the temperature, the humidity and the shading of the greenhouse. I measure the temperature with thermometer chip, the relative humidity with an outer module and the brilliance with a phototransistor. The device controls the relays according to the actual and desired values. The relays are used to switch the heater, the humidor and the shade actuating motor.
In the course of the firmware writing of the devices, I got acquainted with the I2C, SPI and USART interfaces and the peripherals of the AtMega32 microcontroller. I developed a fix instruction format for the communication between the transmitter and receiver device. With this, the base can address the peripherals and disposes of the data to be transmitted.
The planned system can be applied for control the environmental properties of the greenhouse.