Overview
Things
Story

HARDWARE CONNECTIONS
SOFTWARE SETUP
LOGIC AND STRUCTURE BEHIND THE CODE

Published March 20, 2020 © GPL3+

Automated Traffic Light System

Using Bolt WiFi Module, an easy to use, low cost and simple Automated Traffic Light System has been developed in this prototype.

IntermediateFull instructions provided1 hour839

Things used in this project

Hardware components

Breadboard (generic)

Jumper wires (generic)

Resistor 330 ohm

5 mm LED: Red

Representing our RED Light

5 mm LED: Yellow

Representing our YELLOW Light

5 mm LED: Green

Representing our GREEN Light

Bolt IoT Bolt WiFi Module

Software apps and online services

Bolt IoT Bolt Cloud

Ubuntu

Story

Traffic Signals play an important role in our day-to-day life. They not only help movement and but also conduct an orderly flow of vehicles.
We all have got stuck in situations where non-working Traffic Lights have caused a mayhem of traffic leading to more likelihood of mishaps.
As they say prevention is better than cure, this prototype is of an automated traffic signal system which can be easily programmed according to the varying situations.

HARDWARE CONNECTIONS -

Setting up our LED's -

1) Connect the 3 LED's to the breadboard, preferably in the order of

RED - YELLOW - GREEN

2) Connect 330 Ohm Resistor to the breadboard, such that it is connected positive end(longer leg) of Each Led

3) Now, connect one end end of Male to Male Jumper Wire to breadboard, such that it is connected with other end of the Resistor for each LED.

4) The remaining end of Jumper Wires are to be connected to the digital pins of Bolt WiFi Module. In this case, I have taken digital pins 0, 1, 2 for RED, YELLOW, GREEN respectively.

5) Connect a Jumper wire from GND pin of Bolt WiFi Module to the breadboard.

6) Using Jumper Wires, connect negative end(shorter leg) of each LED to the GND pin Wire on the Breadboard.

RED-0,YELLOW-1,GREEN-2.Notice each LED is connected to GND

7) Thus, in this effective setup we have ensured, each LED is connected to ground as well as Digital Pins and with Resistors in Place.

8) After connection, power on the Bolt device and connect it to the internet-enabled wifi network and log in to your Ubuntu and create a Python file.

SOFTWARE SETUP

The Python coding for this project has been done in Ubuntu (Linux).

Python3 is used in this case.

Make sure, Bolt Python Libraries are installed to control our WiFi Module.

LOGIC AND STRUCTURE BEHIND THE CODE:

Before writing our program, we need to make a configuration file which will have the specific keys for each user/device. The advantage of this is that each user will only have to change the contents the configuration file to use the product.

from boltiot import Bolt

import time

from time import sleep

api_key = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"

device_id = "BOLTXXXXX"

mybolt = Bolt(api_key, device_id)

Now let's look into the commands needed to control our LED.

1) mybolt.digitalWrite('0', 'HIGH')

2) mybolt.digitalWrite('0', 'LOW')

These commands are used to switch on/off a LED light. 0 stands for the pin number, to which LED is connected (can be 0/1/2/3/4 depending upon circuit) and LOW/HIGH are the control states.

Notice that we have called time and sleep modules respectively.

import time

from time import sleep

We need them to add delay(timer) to control our Traffic Lights in a proper and timely sequence.

In real life, most of the time we observe that ONE Traffic Light is switched on at a time, and others are off.
Therefore, we will use one function for each traffic light. It is required that, when one light is switched on, others are to be switched off. For example: When RED light is switched on, other 2 lights - yellow and green are switched off

RED ON,OTHERS OFF

Thus, for each Traffic Light - Red, Yellow and Green, we are going to create a function which switches on the RESPECTIVE LIGHT and switches OFF all the others.
Thus, in the main code, we are just going to call our functions according to the sequence we want.
Using time.sleep() a delay is added, before next function is to be executed.
A stop()(optional) is added, which switches off all the lights.
For simplicity sake, in this prototype, we run the Traffic Light Sequence of,
RED (5 secs) - YELLOW (3 secs) - GREEN (5 secs)
Using a While loop, the sequence is executed again and again automatically for 'n' number of times. (Here, 3 times the loop is executed).
The code and its explanation is given in the Code file.
By using functions respectively, we ensure flexibility and code-reusability
Advantage of using functions is that the sequence and the time for which each Traffic Light is to be used can be varied easily depending on the requirement
Moreover, according to the traffic schedule, the number of times the sequence is to be executed can be varied also.
For busy traffic areas, by adding an infinite Loop, the Traffic Lights can be used continuously i.e (24x7)

Output

Automated Traffic Light

from boltiot import Bolt                        #Importing Bolt Libraries
import time                                     #Importing Time Module
from time import sleep                          #Importing Sleep Module
api_key = "xxxxxxxxxxxxxxxxxxxx"                #Insert your API-KEY
device_id = "BOLTXXXXXXX"                       #Insert your device ID
mybolt = Bolt(api_key, device_id)

def red():                                    #Function FOR Red Light
    print(mybolt.digitalWrite('2', 'LOW'))    #Switch OFF Green
    print(mybolt.digitalWrite('0', 'HIGH'))   #Switch ON RED
    print(mybolt.digitalWrite('1', 'LOW'))    #Switch OFF Yellow
def yellow():
    print(mybolt.digitalWrite('0', 'LOW'))    #Switch OFF RED
    print(mybolt.digitalWrite('1', 'HIGH'))   #Switch ON Yellow
    print(mybolt.digitalWrite('2', 'LOW'))    #Switch OFF Green
def green():
    print(mybolt.digitalWrite('0', 'LOW'))    #Switch OFF RED
    print(mybolt.digitalWrite('1', 'LOW'))    #Switch OFF Yellow
    print(mybolt.digitalWrite('2', 'HIGH'))   #Switch ON Green
def stop():                                   #Switch off All lights(optional)
    print(mybolt.digitalWrite('0', 'LOW'))
    print(mybolt.digitalWrite('1', 'LOW'))
    print(mybolt.digitalWrite('2', 'LOW'))
def start():                                  #Our Sequence function R-Y-G
    i=0
    while i<3:                                #Executing Sequence for 3 times
            red()                             #RED LIGHT
            time.sleep(5)                     #Hold five seconds
            yellow()                          #YELLOW LIGHT
            time.sleep(3)                     #HOLD three seconds
            green()                           #GREEN LIGHT
            time.sleep(5)                     #Hold five seconds
            i=i+1                         
    else:
            stop()                            #Switch off lights after loop
start()                                       #main program

Credits

Siddharth Sali

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Automated Traffic Light System

Automated Traffic Light System

Things used in this project

Hardware components

Software apps and online services

Story

HARDWARE CONNECTIONS -

SOFTWARE SETUP

LOGIC AND STRUCTURE BEHIND THE CODE:

Code

Automated Traffic Light

Credits

Siddharth Sali

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