1. RUNWAY LIGHTS CHECKER

2. Objective
This design aims to create a functional prototype of RUNWAY LIGHTS CHECKER using a PIC16F877A with a LED indicator for the output.
1. To be able to design a PIC-based circuit for the checking of Runway Lights.
2. To be able to display which among the lights is defective and which is working.
3. To be able to display only one output using two multiplexers.
4. To be able to have more than one mode of checking the runway lights.
5. To be able to synchronize the checking of lights using two multiplexers.

3. Scope and Limitation
1. It can check up to a maximum of 16 runway lights only.
2. When power cuts off, the project will not work since there is no backup power.

4. Significance This study can be beneficial to the following:
CAAP-AIR NAVIGATION SPECIALIST. Since the this design is to check the Runway lights, these people will not be roaming around the runway anymore just to see if there is a defective light.
MALLS, PARKS and HOTELS. Even though this project is designed for the checking of runway lights, this can also be applied for the checking of lights in malls, parks and in hotels.

5. START FLOW CHART END YES NO YES NO Is Interrupt Switch Pressed?
Use One-to-Sixteen Count Mode
Use Normal Checking Mode
YES NO
Is Display = 16?
END

6. PIC LIGHTS 1-8 LIGHTS 9-16 1-16 COUNT SWITCHES SENSOR 1-8 SENSOR 9-16
BLOCK DIAGRAM
LIGHTS
1-8
LIGHTS
9-16
1-16 COUNT
SWITCHES
PIC
SENSOR
1-8
SENSOR
9-16
SEVEN SEGMENT
ONES PLACE
SEVEN SEGMENT
TENS PLACE
MUX2
MUX1
NOT GATE 1
NOT GATE 2
OR GATE
INDICATOR

7. Table 1: PIC16F877A, MUX’s, Seven Segment and Output Indicator
MULTIPLEXER A
MULTIPLEXER B
7-Segment Display
Output LED Indicator
Data in Port C
Data from Port A to select inputs
Corresponding # of light to be checked
Corresponding # of light to be
checked
00000
----- 00
00001 1 01
1/0
00010 2 02
00011 3 03
00100 4 04
00101 5 05
00110 6 06
00111 7 07
01000 8 08
01001 09
01010 10
01011 11
01100 12
01101 13
01110 14
01111 15
10000 16
10001 to 11111 EE

8. Table 2: Sensor and AND Gate
Comparator 1
Comparator 2
AND Gate
Comparator 3 V+ V-
Output X Y
3.8V
3.2V 1
1.67V 5V
2.5V
5.0V mV

9. Power Supply

10. Current and Voltage Sensor

11. Main Board Circuit

12. Computations DELAY: movlw 0x01 ;A movwf 0x21 movlw 0x25 ;B movwf 0x22
movlw 0x01 ;A
movwf 0x21
movlw 0x25 ;B
movwf 0x22
movlw 0x06 ;C
movwf 0x23
loop
decfsz 0x21, 1
goto loop
decfsz 0x22, 1
decfsz 0x23, 1
return
Delay total = 6 µs + [3{A + [256 (B-1)] + [65280(C-1)]}] µs + [2{B + [256(C-1)]}] µs + (2C) µs
Delay total = 6 µs + [3{1 + [256 (25-1)] + [65280(6-1)]}] µs + [2{25 + [256(6-1)]}] µs + [2(6)] µs
Delay total = us or s

13. LED Resistors:
R = (5V-0.7V)/20mA
R = 215 ohms  330 ohms
Seven Segment Resistors:
Comparator:
C1: V+ = 5V(3K ohms)/4K ohms = 3.75V
V- = 2.9V
C2: V+ = 2.9V
V- = 5V(1K ohms)/3K ohms = 1.67V
C3: V+ = 5V or mV
V- = 5V(1K ohms)/2K ohms = 2.5V

14. One-to Sixteen Count Mode
Table3.1 (Trial1)
RLN
7-SEGMENT DISPLAY
LIGHT STATUS
INDICATOR
REMARKS 01
Good 1 OK 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16

15. Table3.2 (Trial2) RLN 7-SEGMENT DISPLAY LIGHT STATUS INDICATOR REMARKS01
Bad OK 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16

16. Table3.3 (Trial3) RLN 7-SEGMENT DISPLAY LIGHT STATUS INDICATOR REMARKS01
Good 1 OK 02
Bad 03 04 05 06 07 08 09 10 11 12 13 14 15 16

17. Normal checking mode Table4.1 (Trial 1) RLN SWITCH LIGHT STATUS
INDICATOR
REMARKS 01
00001
Good 1 OK 02
00010 03
00011 04
00100 05
00101 06
00110 07
00111 08
01000 09
01001 10
01010 11
01011 12
01100 13
01101 14
01110 15
01111 16
10000

18. Table4.2 (Trial1) RLN SWITCH LIGHT STATUS INDICATOR REMARKS 01 00001
Bad OK 02
00010 03
00011 04
00100 05
00101 06
00110 07
00111 08
01000 09
01001 10
01010 11
01011 12
01100 13
01101 14
01110 15
01111 16
10000

19. Table4.3 (Trial3) RLN* SWITCH LIGHT STATUS INDICATOR REMARKS 01 00001
Good 1 OK 02
00010
Bad 03
00011 04
00100 05
00101 06
00110 07
00111 08
01000 09
01001 10
01010 11
01011 12
01100 13
01101 14
01110 15
01111 16
10000

20. CONCLUSION
After performing several trials, it can be observed that the objectives of this system were met. Therefore, this design is fully functional.

21. Recommendation
For further development of this study, the researchers recommend the following:
To have a data storage for this system.
To make this a fully automated checker.