This project works as a digital clock wherein a user can also set alarm. Additionally, it also works as a digital thermometer to specify the ambient temperature. Both, the clock and temperature are displayed on a 16x2 LCD screen using the 8051 microcontroller (AT89C51). AT89C51 is an eight bit controller which belongs to the 8051 family of microcontrolers.
This project incorporates the functionality of a digital clock and a digital thermometer. The digital clock works in 12 hour mode and is configured by programming the 8051 microcontroller (AT89C51). The program uses a delay function for producing a delay of 1 second. The clock and alarm times can be set through a set of external tactile switches.
The digital thermometer employs a temperature sensor LM35. The sensor responds to the temperature change by giving varying output. These analog signals of LM35 are converted to digital equivalent by ADC0804. The reference voltage (Vref) should be set properly corresponding to the desired temperature range. The data bits are taken as input by the microcontroller at port P0. The microcontroller AT89C51 also gives control signals to ADC0804.