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
