had this posted in the wrong topic, hopefully someone can shed some light on this project?
I am currently requiring some help with a project involving a HC-SR04 Ultrasonic Sensor to control a Solenoid so that the rate at which the solenoid is pushing against an object can be controlled by a hand movement in front of the ultrasonic sensor, ranging from about 0 (being the fastest rate) - 100cm (being the slowest rate)
So far I have gotten my code to turn an LED on when the reading in the serial monitor is between 2 and 50
hopefully you can make some sense of it:
int ledPin = 4;
int dist; //how far the object is away from the module(cm)
int val = 0;
#define trig 11
#define echo 12
void setup() {
Serial.begin (9600);
pinMode(echo, INPUT);
pinMode(trig, OUTPUT);
pinMode(ledPin, OUTPUT);
}
void loop() {
int duration, distance;
digitalWrite(trig, HIGH);
delayMicroseconds(10);
digitalWrite(trig, LOW);
//receive the trigger signal echo, and calculate cm to the object
val= pulseIn(echo, HIGH);
dist= val/58; //converts raw to cm, valueSensor/74/2 = inches
Serial.println(dist);
if (dist >= 50 || dist <= 2)
{
digitalWrite(ledPin, LOW);
}
else {
digitalWrite(ledPin, HIGH);
}
}
all I am wondering now is how the heck I can create a slow - fast blink rate of the LED determined by the 0-200 serial reading I am getting (if i get the LED to blink fast to slow, I can then use my ULN2003AN chip to control a solenoid to turn on and off in the same motion the LED does)
Thanks, would love some help! I hope that is enough information!
working with this code now, I can read out the values of the ultrasonic sensor as cm
/* Ping))) Sensor
This sketch reads a PING))) ultrasonic rangefinder and returns the
distance to the closest object in range. To do this, it sends a pulse
to the sensor to initiate a reading, then listens for a pulse
to return. The length of the returning pulse is proportional to
the distance of the object from the sensor.
The circuit:
* +V connection of the PING))) attached to +5V
* GND connection of the PING))) attached to ground
* SIG connection of the PING))) attached to digital pin 7
http://www.arduino.cc/en/Tutorial/Ping
created 3 Nov 2008
by David A. Mellis
modified 30 Aug 2011
by Tom Igoe
This example code is in the public domain.
*/
// this constant won't change. It's the pin number
// of the sensor's output:
const int pingPin = 7;
int ledPin = 13;
void setup() {
// initialize serial communication:
Serial.begin(9600);
}
void loop()
{
// establish variables for duration of the ping,
// and the distance result in inches and centimeters:
long duration, cm;
// The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
// Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(5);
digitalWrite(pingPin, LOW);
// The same pin is used to read the signal from the PING))): a HIGH
// pulse whose duration is the time (in microseconds) from the sending
// of the ping to the reception of its echo off of an object.
pinMode(pingPin, INPUT);
duration = pulseIn(pingPin, HIGH);
// convert the time into a distance
cm = microsecondsToCentimeters(duration);
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(10);
}
long microsecondsToCentimeters(long microseconds)
{
// The speed of sound is 340 m/s or 29 microseconds per centimeter.
// The ping travels out and back, so to find the distance of the
// object we take half of the distance travelled.
return microseconds / 29 / 2;
}
now I am wondering how i can get it to read only between 0 - 100cm , and then convert that to the blink of an LED... its strange I can only get it to work with a potentiometer, but when I try to use the Ultrasonic sensor it will not read it the same as an analog read...... I dont really understand what is going on with the blink-delay tutorial.... and how I can relate it to this as it is not an analog read..
