Blockage IR sensor

Projects General Guidance
1

Hello !

I'm quite new to programing but I understand electronics but the problem I'm having is, I'm building a seed counting system for a seed drill but eventually it will be counting seed and telling me seed population over an given area and lots of other things but I haven't got time to do that before planting season so all I want for this year is just a simple blockage system that will light an led and sound a buzzer when it stops counting seed/ stops pulsing. Iv built the sensors my self and its just a brake beam inferred but it can detect small and large seed and when the beam gets broken it pulls the signal wire/ digital input to ground. So all I want it to do is if the digital input stays high or sees no pulse for say 3 seconds it lights the led and buzzer and as soon as it goes low or starts pulsing again the led goes off but its got to be doing this for 8 sensors at a time and it cant be spending to long reading one sensor. It is very simple in theory but I cant seem to find any examples anywhere so I would be very grateful for some help.

Thanks, Chris. ;D

2

so all I want for this year is just a simple blockage system that will light an led and sound a buzzer when it stops counting seed/ stops pulsing.

How will the Arduino know that that has happened?

So all I want it to do is if the digital input stays high or sees no pulse for say 3 seconds it lights the led and buzzer and as soon as it goes low or starts pulsing again the led goes off but its got to be doing this for 8 sensors at a time and it cant be spending to long reading one sensor.

So what is the problem?

It is very simple in theory

In practice, too.

but I cant seem to find any examples anywhere so I would be very grateful for some help.

What are you currently able to do? Can you detect that the sensor is/is not seeing a seed? Can you tell when the transition happens? If so, record the time.

Periodically, as in on every pass through loop(), see if now minus then (when a seed was last detected) is greater than the desired interval. If so, sound the alarm.

The blink without delay and state change detection examples provide all the pieces you need.

3

Thanks for your reply!
The sensor is connected to an digital input with a resistor pulling it to 5v.
Every time a seed passes thro the sensor the digital input pin on the board will see it go to low the back to high being one seed has passed but I just want it to if the input state is constantly high for more than 3 sec then switches on an led and buzzer. But keeping in mind that multiple seeds are falling/ second.
But I don't want it to see a high state start timing and look at the pin again in 3 seconds as it could catch it at a high state again after a seed passed in that 3 seconds but that's all I can figger out what to do at the moment.

I just cant work out what code to write for below:

Read pin 22- if pin is high start reading for 3 seconds if at any point the state goes to low cancel counting and carry on loop (to minimise time wasting)
Has pin 22 stayed high constantly for >3 seconds
yes= turn on ledpin 23
no= turn off ledpin23.

4

You have to remember the time when a sensor was unblocked. Like this:

if (digitalRead(pin) pinTime=millis();
if (millis() - pinTime > interval) digitalWrite(LED, ON); //alert
else digitalWrite(LED, OFF);

Repeat for each sensor.

5

Got it working!

const int sen1 = 22;
const int sen2 = 23;
const int sen3 = 24;
const int sen4 = 25;
const int sen5 = 26;
const int sen6 = 27;
const int sen7 = 28;
const int sen8 = 29;

const int led1 = 32;
const int led2 = 33;
const int led3 = 34;
const int led4 = 35;
const int led5 = 36;
const int led6 = 37;
const int led7 = 38;
const int led8 = 39;

int senState1 = 0; // current state of the sensor
int senState2 = 0; // current state of the sensor
int senState3 = 0; // current state of the sensor
int senState4 = 0; // current state of the sensor
int senState5 = 0; // current state of the sensor
int senState6 = 0; // current state of the sensor
int senState7 = 0; // current state of the sensor
int senState8 = 0; // current state of the sensor

unsigned long pinTime1 = 0; // the time button is hold
unsigned long pinTime2 = 0; // the time button is hold
unsigned long pinTime3 = 0; // the time button is hold
unsigned long pinTime4 = 0; // the time button is hold
unsigned long pinTime5 = 0; // the time button is hold
unsigned long pinTime6 = 0; // the time button is hold
unsigned long pinTime7 = 0; // the time button is hold
unsigned long pinTime8 = 0; // the time button is hold

const long interval = 2000;

void setup() {

pinMode(sen1, INPUT);
pinMode(sen2, INPUT);
pinMode(sen3, INPUT);
pinMode(sen4, INPUT);
pinMode(sen5, INPUT);
pinMode(sen6, INPUT);
pinMode(sen7, INPUT);
pinMode(sen8, INPUT);

pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT);
pinMode(led4, OUTPUT);
pinMode(led5, OUTPUT);
pinMode(led6, OUTPUT);
pinMode(led7, OUTPUT);
pinMode(led8, OUTPUT);
}

void loop() {

// 1 read input pin sen1:
senState1 = digitalRead(sen1);
if (digitalRead(sen1)==LOW)pinTime1 = millis();
if (millis() - pinTime1 > interval)
digitalWrite(led1, HIGH); //alert}
else digitalWrite(led1, LOW);

// 2 read pin sen2:
senState2 = digitalRead(sen2);
if (digitalRead(sen2)==LOW) pinTime2 = millis();
if (millis() - pinTime2 > interval)
digitalWrite(led2, HIGH); //alert
else digitalWrite(led2, LOW);

// 3 read input pin sen3:
senState3 = digitalRead(sen3);
if (digitalRead(sen3)==LOW) pinTime3 = millis();
if (millis() - pinTime3 > interval)
digitalWrite(led3, HIGH); //alert
else digitalWrite(led3, LOW);

// 4 read input pin sen4:
senState4 = digitalRead(sen4);
if (digitalRead(sen4)==LOW) pinTime4 = millis();
if (millis() - pinTime4 > interval)
digitalWrite(led4, HIGH); //alert
else digitalWrite(led4, LOW);

// 5 read input pin sen5:
senState5 = digitalRead(sen5);
if (digitalRead(sen5)==LOW) pinTime5 = millis();
if (millis() - pinTime5 > interval)
digitalWrite(led5, HIGH); //alert
else digitalWrite(led5, LOW);

// 6 read input pin sen6:
senState6 = digitalRead(sen6);
if (digitalRead(sen6)==LOW) pinTime6 = millis();
if (millis() - pinTime6 > interval)
digitalWrite(led6, HIGH); //alert
else digitalWrite(led6, LOW);

// 7 read input pin sen7:
senState7 = digitalRead(sen7);
if (digitalRead(sen7)==LOW) pinTime7 = millis();
if (millis() - pinTime7 > interval)
digitalWrite(led7, HIGH); //alert
else digitalWrite(led7, LOW);

// 8 read input pin sen8:
senState8 = digitalRead(sen8);
if (digitalRead(sen8)==LOW) pinTime8 = millis();
if (millis() - pinTime8 > interval)
digitalWrite(led8, HIGH); //alert
else digitalWrite(led8, LOW);

}

6

Hi,
What model Arduino is it.

Can you please post a copy of your sketch, using code tags?
They are made with the </> icon in the reply Menu.
See section 7 http://forum.arduino.cc/index.php/topic,148850.0.html

Good to see you have it going.

Tom.... :slight_smile:

7

When you find yourself tempted to suffix variable names with numbers, such as this:

const int sen1 = 22;
const int sen2 = 23;
const int sen3 = 24;
const int sen4 = 25;
const int sen5 = 26;
const int sen6 = 27;
const int sen7 = 28;
const int sen8 = 29;

const int led1 = 32;
const int led2 = 33;
const int led3 = 34;
const int led4 = 35;
const int led5 = 36;
const int led6 = 37;
const int led7 = 38;
const int led8 = 39;

then it is time to learn about arrays - and in this case, arrays of structs.

8

Save more space - make them byte, vs int. Nothing higher than 255 there.