trafficLight

README

traffic light sample program for two trafficlights

Abstract

Two trafficlights TL1 and TL2 are simulated (see below their location in the crossing). A traffic light manager loads different traffic light programs in an endless loop, runs them for 15 seconds and switches to the next program. All programs are separated by a 5 second warning blink program which blinks the yellow LEDs. CTRL-C will terminate the endless loop. A video which shows the traffic light in action is available here.

Either build the executable for Raspberry with buildAndRun or just execute trafficlight_arm.

Location of traffic lights

         TL1
          |  
      ---   --- TL2
          |

Configuration

Mapping of Raspberry pins to GPIOs and traffic light programs can be configured. A default configuration exists and

1. uses the BCM GPIO mapping
2. three sample traffic light programs

The mapping from GPIOs to pins is defined in GPIO.json. Traffic light programs are defined in programs.json.

Mapping of GPIO to LEDs

• TL1: uses GPIO2-GPIO4 LEDs red(2), yellow(3) and green(4)
• TL2: uses GPIO5-GPIO7 LEDs red(5), yellow(6) and green(7)

Default trafficlight configuration

GPIO to Pin mappings

GPIO.json

[
17, 18,
27, 22, 23,
24, 25, 4
]

17: GPIO0 (unused)
18: GPIO1 (unused)
27: GPIO2 is BCM pin 27 which is trafficlight1 red LED
22: GPIO3 is BCM pin 22 which is trafficlight1 yellow LED
...
25: GPIO6 is BCM pin 25 which is trafficlight2 yellow LED
04: GPIO7 is BCM pin 4 which is trafficlight2 green LED

Traffic light program definitions

Programs are a sequence of tuples which define the LEDs to light and how long they are displayed (number of ticks from traffic manager).

lights

lights	green	yellow	red
0
1	on
2		on
3			on
4		on	on

ticks

Defines the duration to light LED and is the number of ticks received from traffic manager

programs.json

{
   "Normal1": {
      "name": "Normal1",
      "phases": [
         {
            "lights": 1,
            "ticks": 3
         },
         {
            "lights": 2,
            "ticks": 1
         },
         {
            "lights": 3,
            "ticks": 1
         },
         {
            "lights": 3,
            "ticks": 1
         },
         {
            "lights": 3,
            "ticks": 3
         },
         {
            "lights": 3,
            "ticks": 3
         },
         {
            "lights": 3,
            "ticks": 1
         },
         {
            "lights": 3,
            "ticks": 1
         },
         {
            "lights": 4,
            "ticks": 1
         },
         {
            "lights": 1,
            "ticks": 3
         }
      ],
      "clock_speed": 1000000000
   },
   "Normal2": {
      "name": "Normal2",
      "phases": [
         {
            "lights": 1,
            "ticks": 3
         },
         {
            "lights": 2,
            "ticks": 1
         },
         {
            "lights": 3,
            "ticks": 1
         },
         {
            "lights": 3,
            "ticks": 3
         },
         {
            "lights": 3,
            "ticks": 3
         },
         {
            "lights": 3,
            "ticks": 1
         },
         {
            "lights": 4,
            "ticks": 1
         },
         {
            "lights": 1,
            "ticks": 3
         }
      ],
      "clock_speed": 1000000000
   },
   "Normal3": {
      "name": "Normal3",
      "phases": [
         {
            "lights": 1,
            "ticks": 3
         },
         {
            "lights": 2,
            "ticks": 1
         },
         {
            "lights": 2,
            "ticks": 1
         },
         {
            "lights": 3,
            "ticks": 3
         },
         {
            "lights": 3,
            "ticks": 1
         },
         {
            "lights": 4,
            "ticks": 1
         }
      ],
      "clock_speed": 1000000000
   }
}

Program options

-leds
     Use LEDs connected to GPIOs (run on Raspberry)
-monitor
     Simulate LEDs on screen (default true) (run on any non Raspberry system)