HARDWARE

This project will require following hardware:

a)      1 x PIC16F873A

b)      1 x PJT 11 Printed Circuit Board (PCB)

c)      1 x LCD

d)      1 x Buzzer

e)      2 x Temperature Sensor (LM35)

f)       Other related electronic component

Interface PIC16F873A with Temperature Sensor (LM35)

Signal pin (Vout) from LM35 can be connected to either one of analog input pin (AN0-AN4) except AN3 (pin 5) but make sure the ADC configuration is correct. In fact, pin 5 (Vref+)from PIC should be given for 1V but it may has offset, so a variable resistor (VR1) was installed for voltage adjusting. For more stability, user is recommended add a capasitor (104) between the analog signal and GND for every analog input such as signal from LM35 and variable resistor (VR1).

Interface PIC16F873A with LCD

The 16 header pin should be soldered to the LCD first. The following table shows the LCD (2X16 character) connection:

PIN	PIN NAME	FUNCTION	CONNECTION
1	VSS	Ground	GND
2	VCC	Positive supply for LCD	5V
3	VEE	Contrast adjust connected to a preset for contrast adjusting
4	RS	Select register, select instruction or data register	RA2
5	R/W	Select read or write	GND
6	E	Start data read or write	RA5
7	DB0	Data bus pin	RC0
8	DB1	Data bus pin	RC1
9	DB2	Data bus pin	RC2
10	DB3	Data bus pin	RC3
11	DB4	Data bus pin	RC4
12	DB5	Data bus pin	RC5
13	DB6	Data bus pin	RC6
14	DB7	Data bus pin	RC7
15	LED+	Backlight positive input	5V
16	LED-	Backlight negative input	GND

                                                                    TABLE 1