Traffic Light Code

Viper1 · 2020-06-19 08:40

Hello all, This is my first post and I am a novice to Parallax microcontrollers. I saw this traffic light on a youtube video and having some interest in these types of projects, I just had to try it.

The code below in it's original unedited state (except for ports) but there seems to be some problems with this or I am missing something.

I have studied the code and understand most of it. The code for the most part is running as it should. The Ping sensor is active and displays distance perhaps in mm and does change the switch dependent on distance but I am having difficulty with the reset portion of this code as it does shut off all lights once the LIGHT_ON_TIME is reached but does not seem to reset so the light are active again. I have done some experimenting with the code and changing line 53 from 0 to 1 "timeLightHasBeenOn = timeLightHasBeenOn + 1" does produce a timing output . But my main obstacle is the reset portion of this code I am sure this timer is directly related to my issue as is line 103 "timeLightHasBeenOn = 0".

Any help with this would be greatly appreciated. TY

• I believe the system is suppose to reset after a certain X time but does not
• Would like distance to read in inches and cm and the timer to read actual second.

1.	'Distance constants
2.	GREEN_DISTANCE        CON 11000
3.	YELLOW_DISTANCE      CON 7500
4.	RED_DISTANCE          	CON 4600
5.	CmConstant            	CON 2260
6.	InConstant            	CON 890

7.	'Time constants
8.	LIGHT_ON_TIME         	CON 1000

9.	'Light States
10.	LIGHT_OFF             	CON 0
11.	RED_LIGHT             	CON 1
12.	YELLOW_LIGHT          	CON 2
13.	GREEN_LIGHT           	CON 3

14.	'IO PINS
15.	GREEN_IO_PORT         	CON 13
16.	YELLOW_IO_PORT        	CON 14
17.	RED_IO_PORT           	CON 15
18.	PING1_IO_PORT         	CON 5

19.	'Variables
20.	timeLightHasBeenOn    	VAR Word
21.	distanceSensor1       	VAR Word
22.	lightState            		VAR NIB
23.	distanceFiltered      	VAR Word
24.	distance              	VAR Word
25.	cmDistance           	VAR Word
26.	inDistance            	VAR Word
27.	time                  		VAR Word

28.	'Initialize variables
29.	lightState = LIGHT_OFF
30.	timeLightHasBeenOn = 0
31.	distanceFiltered = 0

32.	'Turn off lights
33.	LOW GREEN_IO_PORT
34.	LOW YELLOW_IO_PORT
35.	LOW RED_IO_PORT

36.	'Loop forever
37.	DO
38.	'Get the distance from sensor #1
39.	PULSOUT PING1_IO_PORT, 5
40.	PULSIN PING1_IO_PORT, 5, distanceSensor1

41.	'cmDistance = cmConstant ** time
42.	'inDistance = inConstant ** time

43.	'DEBUG HOME, DEC5 cmDistance, " cm"
44.	'DEBUG CR, DEC5 inDistance, " in"

45.	distanceFiltered = distanceFiltered - (distanceFiltered/5-distanceSensor1)

46.	distance = distanceFiltered / 5

47.	DEBUG HOME, "distanceRaw = ", DEC5 distanceSensor1, "; distanceFilt = ", DEC5 distance, "; timer = ", DEC5 timeLightHasBeenOn, CR

48.	'Check for car present 
49.	IF (distance < GREEN_DISTANCE) THEN

50.	'If car has just arrived, then turn on the light!!!
51.	IF (timeLightHasBeenOn < LIGHT_ON_TIME) THEN

52.	'Increment timer
53.	timeLightHasBeenOn = timeLightHasBeenOn + 0

54.	'Determine which light: green, yellow, or red
55.	SELECT distance
56.	'Green light - bumper not detected yet
57.	CASE > YELLOW_DISTANCE
58.	IF lightState <> GREEN_LIGHT THEN
59.	lightState = GREEN_LIGHT

60.	'Turn green on
61.	HIGH GREEN_IO_PORT
62.	LOW YELLOW_IO_PORT
63.	LOW RED_IO_PORT
64.	ENDIF

65.	'Yellow light - bumper detected but not at the top height yet
66.	CASE > RED_DISTANCE
67.	IF lightState <> YELLOW_LIGHT THEN
68.	lightState = YELLOW_LIGHT

69.	'Turn yellow on
70.	LOW GREEN_IO_PORT
71.	HIGH YELLOW_IO_PORT
72.	LOW RED_IO_PORT
73.	ENDIF

74.	'Red light - at the top height
75.	CASE ELSE
76.	IF lightState <> RED_LIGHT THEN
77.	lightState = RED_LIGHT

78.	'Turn red on
79.	LOW GREEN_IO_PORT
80.	LOW YELLOW_IO_PORT
81.	HIGH RED_IO_PORT
82.	ENDIF

83.	ENDSELECT

84.	'Car has been here for a while so turn off the light
85.	ELSE
86.	IF lightState <> LIGHT_OFF THEN
87.	lightState = LIGHT_OFF
88.	LOW GREEN_IO_PORT
89.	LOW YELLOW_IO_PORT
90.	LOW RED_IO_PORT
91.	ENDIF
92.	ENDIF

93.	'No car is present
94.	ELSE

95.	'Make sure lights are turned off
96.	IF lightState <> LIGHT_OFF THEN
97.	lightState = LIGHT_OFF
98.	LOW GREEN_IO_PORT
99.	LOW YELLOW_IO_PORT
100.	LOW RED_IO_PORT
101.	ENDIF

102.	'Reset the timer
103.	timeLightHasBeenOn = 0

104.	ENDIF

105.	PAUSE 100

106.	LOOP

107.	END

DaveJenson · 2020-06-19 14:51

Welcome to the Forums!

Which Parallax microcontroller are you using?
Please post your code using the Code directive "C" in the menu bar.

VonSzarvas · 2020-06-19 15:05

Welcome to the forums Viper1 !

As Dave asked above, it looks like Basic Stamp code- so I'll move this to the Basic Stamp forum for you, as you should catch the eye of more Stamp experts that way.

I've added the code tags for you too, just to make the code easier to read.

When you post code next time, then click that C button above the posting text box, and you'll get code tags appear to preserve the code formatting. As always, lot's of little things to help and learn along the way!

Viper1 · 2020-06-19 15:25

Thank you Dave & VonSzarvas. Using the Code directive I understand should preserve code formatting. Good to know

Controller board is a Board of Education USB 28803 using 3 Relays 27715 and a Ping sensor

Viper1 · 2020-06-19 15:29

' {$STAMP BS2}
' {$PBASIC 2.5}

'Distance constants
GREEN_DISTANCE        CON 11000
YELLOW_DISTANCE       CON 7500
RED_DISTANCE          CON 4600

'Time constants
LIGHT_ON_TIME         CON 1000

'Light States
LIGHT_OFF             CON 0
RED_LIGHT             CON 1
YELLOW_LIGHT          CON 2
GREEN_LIGHT           CON 3

'IO PINS
GREEN_IO_PORT         CON 13
YELLOW_IO_PORT        CON 14
RED_IO_PORT           CON 15
PING1_IO_PORT         CON 12

'Variables
timeLightHasBeenOn    VAR Word
distanceSensor1       VAR Word
lightState            VAR Nib
distanceFiltered      VAR Word
distance            VAR Word


'Initialize variables
lightState = LIGHT_OFF
timeLightHasBeenOn = 0
distanceFiltered = 0

'Turn off lights
LOW GREEN_IO_PORT
LOW YELLOW_IO_PORT
LOW RED_IO_PORT

'Loop forever
DO
  'Get the distance from sensor #1
  PULSOUT PING1_IO_PORT, 5
  PULSIN PING1_IO_PORT, 1, distanceSensor1
  distanceFiltered = distanceFiltered - (distanceFiltered/5-distanceSensor1)
  distance = distanceFiltered / 5
  DEBUG HOME, "distanceRaw = ", DEC5 distanceSensor1, "; distanceFilt = ", DEC5 distance, "; timer = ", DEC5 timeLightHasBeenOn, CR

  'Check for car present
  IF (distance < GREEN_DISTANCE) THEN

    'If car has just arrived, then turn on the light!!!
    IF (timeLightHasBeenOn < LIGHT_ON_TIME) THEN

      'Increment timer
      timeLightHasBeenOn = timeLightHasBeenOn + 0

      'Determine which light: green, yellow, or red
      SELECT distance

        'Green light - bumper not detected yet
        CASE > YELLOW_DISTANCE
          IF lightState <> GREEN_LIGHT THEN
            lightState = GREEN_LIGHT
            'Turn green on
            HIGH GREEN_IO_PORT
            LOW YELLOW_IO_PORT
            LOW RED_IO_PORT
          ENDIF

        'Yellow light - bumper detected but not at the top height yet
        CASE > RED_DISTANCE
          IF lightState <> YELLOW_LIGHT THEN
            lightState = YELLOW_LIGHT
            'Turn yellow on
            LOW GREEN_IO_PORT
            HIGH YELLOW_IO_PORT
            LOW RED_IO_PORT
          ENDIF

        'Red light - at the top height
        CASE ELSE
          IF lightState <> RED_LIGHT THEN
            lightState = RED_LIGHT
            'Turn red on
            LOW GREEN_IO_PORT
            LOW YELLOW_IO_PORT
            HIGH RED_IO_PORT
          ENDIF

      ENDSELECT

    'Car has been here for a while so turn off the light
    ELSE
      IF lightState <> LIGHT_OFF THEN
        lightState = LIGHT_OFF
        LOW GREEN_IO_PORT
        LOW YELLOW_IO_PORT
        LOW RED_IO_PORT
      ENDIF

    ENDIF

  'No car is present
  ELSE
    'Make sure lights are turned off
    IF lightState <> LIGHT_OFF THEN
      lightState = LIGHT_OFF
      LOW GREEN_IO_PORT
      LOW YELLOW_IO_PORT
      LOW RED_IO_PORT
    ENDIF

    'Reset the timer
    timeLightHasBeenOn = 0

  ENDIF

  PAUSE 100

LOOP

END

Duane Degn · 2020-06-19 15:30

Viper1 wrote: »

I saw this traffic light on a youtube video

Could you post a link to the YouTube video?

Just copy and paste the URL without any special tags. The forum software automatically embed the video.

Viper1 · 2020-06-19 15:53

Traffic Light YouTube video.

Viper1 · 2020-06-26 20:31

Was hoping for more insight from this forum to my issues with the reset issue in the code. Did I miss something?

Peter Jakacki · 2020-06-27 00:21

I did a Forth version of your code kinda for teaching TAQOZ. But the only timer I have is one that is retriggered by confirmed movement and this counts down and stops at zero. So instead of saying how long the light has been on, it's better to say how much longer it should stay on. What I was trying to do simply translate your code as an exercise but found that there were too many variables being tested unnecessarily such as checking what state it was already in for instance.

The actual code required for the lights was very simple and involves having a small movement routine that tracked the few readings and compared them looking for a sustained change above a small threshold.

If there is movement:
Reload the countdown timer
If it is very close - turn on red light
If it is close but needs to come closer - turn on yellow light
If it is within parking distance (less than "too far away") - turn on green light
If it is too far away - turn off lights (optional)

If there is no movement and timer <> 0
Countdown timer

If timer = 0 then turn off the lights

Viper1 · 2020-06-27 22:27

Thank you Peter, I will consider your option and post my results.

sam_sam_sam · 2021-02-04 12:22

@Viper1 said:
Your Project

Did you finish your project and how does it work

Traffic Light Code

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