arduino Archives - Pieter @ Kraaima

HC-SR04 Ping distance sensor

14/11/2013

Working on a small mockup that should read sensors, [do some stuff here] and send it to clients website/server..

Using a sensor like the HC-SRo4 Ping distanse sensor to send a signal to the RasBotPi when someone walks inside the range is a nice idea for the moment. Although for the project I am working on, this is not the best idea 🙂

But Arduino and a breadboard gives you the power to fool arround and see if it fits your needs.

On twitter I found out about this guy: Hazim Bitar.
His website is http://www.techbitar.com and you can follow him on twitter too. He created an app that reads Arduino sensors using bluetooth. Got me thinking about the final project and how we can overcome the distance without the needs of cable (or to setup a complete wifi network) on the “moving” location.

HC-SR04 on breadboard

Anyway, this sensor came from china (dx.com). There are lots of sketches to find if you do a google. The one I post here works too. Dunno exact where I found it..

/*
 HC-SR04 Ping distance sensor:
 VCC to arduino 5v 
 GND to arduino GND
 Echo to Arduino pin 7 
 Trig to Arduino pin 8

 This sketch originates from Virtualmix: http://goo.gl/kJ8Gl
 Has been modified by Winkle ink here: http://winkleink.blogspot.com.au/2012/05/arduino-hc-sr04-ultrasonic-distance.html
 And modified further by ScottC here: http://arduinobasics.blogspot.com/
 on 10 Nov 2012.
 */

#define echoPin 7 // Echo Pin
#define trigPin 8 // Trigger Pin
#define LEDPin 13 // Onboard LED

int maximumRange = 200; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration, distance; // Duration used to calculate distance

void setup() {
 Serial.begin (9600);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
 pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)
}

void loop() {
/* The following trigPin/echoPin cycle is used to determine the
 distance of the nearest object by bouncing soundwaves off of it. */ 
 digitalWrite(trigPin, LOW); 
 delayMicroseconds(2); 

 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10); 

 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);

 //Calculate the distance (in cm) based on the speed of sound.
 distance = duration/58.2;

 if (distance &gt;= maximumRange || distance &lt;= minimumRange){
 /* Send a negative number to computer and Turn LED ON 
 to indicate "out of range" */
 Serial.println("-1");
 digitalWrite(LEDPin, HIGH); 
 }
 else {
 /* Send the distance to the computer using Serial protocol, and
 turn LED OFF to indicate successful reading. */
 Serial.println(distance);
 digitalWrite(LEDPin, LOW); 
 }

 //Delay 50ms before next reading.
 delay(50);
}

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/*

HC-SR04 Ping distance sensor:

VCC to arduino 5v

GND to arduino GND

Echo to Arduino pin 7

Trig to Arduino pin 8

This sketch originates from Virtualmix: http://goo.gl/kJ8Gl

Has been modified by Winkle ink here: http://winkleink.blogspot.com.au/2012/05/arduino-hc-sr04-ultrasonic-distance.html

And modified further by ScottC here: http://arduinobasics.blogspot.com/

on 10 Nov 2012.

*/

#define echoPin 7 // Echo Pin

#define trigPin 8 // Trigger Pin

#define LEDPin 13 // Onboard LED

int maximumRange = 200; // Maximum range needed

int minimumRange = 0; // Minimum range needed

long duration, distance; // Duration used to calculate distance

void setup() {

Serial.begin (9600);

pinMode(trigPin, OUTPUT);

pinMode(echoPin, INPUT);

pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)

}

void loop() {

/* The following trigPin/echoPin cycle is used to determine the

distance of the nearest object by bouncing soundwaves off of it. */

digitalWrite(trigPin, LOW);

delayMicroseconds(2);

digitalWrite(trigPin, HIGH);

delayMicroseconds(10);

digitalWrite(trigPin, LOW);

duration = pulseIn(echoPin, HIGH);

//Calculate the distance (in cm) based on the speed of sound.

distance = duration/58.2;

if (distance >= maximumRange || distance <= minimumRange){

/* Send a negative number to computer and Turn LED ON

to indicate "out of range" */

Serial.println("-1");

digitalWrite(LEDPin, HIGH);

}

else {

/* Send the distance to the computer using Serial protocol, and

turn LED OFF to indicate successful reading. */

Serial.println(distance);

digitalWrite(LEDPin, LOW);

}

//Delay 50ms before next reading.

delay(50);

}

Gertboard ATmega IO vs. Arduino Pins

24/08/2013

The printing on the Gertboard indicated the port and pin numbers internal to the Atmega microcontroller…

However this is normally hidden from the user by the Arduino’s “wiring” library and rather than refer to (e.g.) Port B, bit 5, you’d normally refer to “pin 15″.

The mapping is fairly straightforward, but to help you connect wires to pins on the Gertboard, here is a handy table to let you see what the connections are:

See source:
https://projects.drogon.net/raspberry-pi/gertboard/gertboard-atmega-io-vs-arduino-pins/

Setup Arduino IDE serial monitor on the Raspberry Pi

24/08/2013

The Arduino IDE does not understand names such as /dev/ttyAMA0.

One suggestion is to

sudo ln -s /dev/ttyAMA0 /dev/ttyUSB9

1	sudo ln -s /dev/ttyAMA0 /dev/ttyUSB9

and restart the Arduino IDE.

This creates an alias to /dev/ttyAMA0 which the IDE may understand.

Source:
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=42&t=28908