Here is a microcontroller based wireless equipment controller that can switch on or off upto four devices at a desired time interval set by the user in the transmitter. The devices can be controlled remotely from a distance upto 30 metres from the transmitter. In the transmitter, an LCD module is used to show the device numbers and preset control time for the devices (00 to 99 seconds). The 8-bit AT89C51 microcontroller is the main controlling part of the transmitter section. It is connected to the LCD module, input switches and encoder IC (HT12E). The device control program is stored in the memory of the microcontroller to control the devices as per the time out settings done through input switches S1 through S4. The TRX -434 RF transmitter module uses a digital modulation technique called ASK (Amplitude Shift Keying) or on-off keying.
The RX-434 radio receiver module receives the ASK signal from TRX-434. The HT12D decoder demodulates the received address and data bits. Concepts of wireless RF communication and automation with AT89C51 microcontroller are used here.
Wireless Equipment Control Using AT89C51 ECE Main Project Full Report download