Hi everyone;
I just design a circuit and a program using an LCD display to count the passager going in or out for a school bus. I been driving a school bus - I have a ABZ licence <- A : Tractor Trailer & 72 pass School Bus & Air Brake Endorsment ( 20 pass - most of the time & 72 pass recently - summer run ) for the past 8 years. ( I know I am not working in electronics - I was in the mid 90's but was layoff and unlucky to find employment in my old field ). The raison I am building a counter system, is because I am doing Tennis Canada - Rogers Cup to drive peoples from parking lot to the Rexale Center ( located at York University in Toronto ) and the client request to count the number of people going in/out of the bus.
The system included : a photo-transistor sensor to count passager - light source is a LEDs Flash Light, a trip reset switch and a stop counting switch. I operate that way : I am full or at the last stop, a trip number will show ( ## <=48 ) The number 48 is the max adult can fit inside a school bus, I select a stop counting, when I arrive, I reset the trip and select counting mode.
My system work , BUT the opto sensor is "so-so" ( Too sensive, not sensitive, can not make it mind ) It look like I will re-design using op-amp has a comparator.
Here the code, sensor schematics and a picture. Let me know of what you guys thinks.
/*
size = 3604
To count the number of passagers going into a School Bus.
Display the number of passager per trip and indicated when
48 is reach - FULL ( max capacity - adult only )
Also indicated the total number of passagers that use the bus
Use :
1 LCD Display - parralel type
1 photo-transistor
1 push-on switch
1 SPST switch
1 10 K pot
1 220 R for display backlight
4 1 K resistors
1 NPN 2N3904
1 4.7 K resistor
Created by Serge J Desjardins aka techone
Toronto, Ontario Canada
*/
#include <LiquidCrystal.h> // Library for LCD
LiquidCrystal lcd(7, 8, 9, 10, 11, 12); // LCD interface pin
const byte pinin[2]={6,5,}; // Input pin
boolean pudo; // Pick-up / Drop-off switch
boolean stz; // Start to Zero - reset for a new trip
byte roll; // just a count variable
byte trip; // number of passager during the trip
unsigned int pass; // total of passagers
unsigned int passone; // Use to count the passagers
volatile byte count; // counting the people from the opto sensor
void setup()
{
for (roll=0;roll>3;roll++)
{
pinMode (pinin[roll], INPUT); // init the input pins
}
attachInterrupt (1, passcount, FALLING); // set the opto sensor using interrupt
//Init the LCD display to show the info
lcd.begin(16, 2);
lcd.clear();
lcd.print("Trip:");
lcd.setCursor(0,1);
lcd.print("Total Pass:");
// Init the variable to zero
pudo=LOW;
stz=LOW;
trip=0;
pass=0;
passone=0;
count=0;
}
void loop()
{
pudo= digitalRead (pinin[0]); // Read DO/PU switch
delay (100);
if (pudo==HIGH)
// Display the paasager info
{
lcd.setCursor(5,0);
lcd.print(trip,DEC);
lcd.setCursor(11,1);
lcd.print(pass,DEC);
if (trip>=48 ) // indicate when you are at max capacity which is 48
{
lcd.setCursor(8,0);
lcd.print("Full");
}
trip=count; // transfer volatile data into trip
pass=trip+passone;
}
else
{
count=0; // make sure the count is keep zero
stz=digitalRead (pinin[1]); // check for reset data switch
delay (100);
if (stz==HIGH) // reset the display to start recounting passager
{
trip=0;
passone=pass; // updated total passager
lcd.setCursor (5,0);
lcd.print(trip,DEC);
lcd.setCursor (6,0);
lcd.print(" ");
}
}
}
void passcount() // Interrupt subroutine
{
count++;
}
