need help please?

Projects Programming
1

Can anyone help me with my code to make a servo work with an hc-sr04 ping sensor? no matter how many times I tried to write it differently the servo does not work! I am just wanting the servo to move 180 if the ping is less than 50 cm and 0 if it is more than 50 cm! any help would be greatly appreciated thanks! here's my code
#include <Servo.h>

// ---------------------------------------------------------------------------
// Example NewPing library sketch that does a ping about 20 times per second.
// ---------------------------------------------------------------------------
Servo myservo;
#include <NewPing.h>

#define TRIGGER_PIN 3 // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN 2 // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.

void setup() {
myservo.attach(6);
Serial.begin(115200); // Open serial monitor at 115200 baud to see ping results.
}

void loop() {

delay(50); // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
unsigned int uS = sonar.ping(); // Send ping, get ping time in microseconds (uS).
Serial.print("Ping: ");
Serial.print(uS / US_ROUNDTRIP_CM); // Convert ping time to distance in cm and print result (0 = outside set distance range)
Serial.println("cm");

{
if (MAX_DISTANCE > 50)

{
myservo.write(180);
delay(15);
}
if (MAX_DISTANCE < 50)
{
myservo.write(0);
delay(15);
}
}
}

2

kevintutor74:

  if (MAX_DISTANCE > 50) {

myservo.write(180);
   delay(15);
 }
 if (MAX_DISTANCE < 50) {
   myservo.write(0);
   delay(15);
 }

When you compare two constants you never get answers that change. You should calculate AND SAVE the distance in cm and compare THAT to 50.

3

Is the curly bracket after Serial.print(cm); misplaced? Use the auto format to indent your code. Use ctrl-t to auto format.

4

What happens if MAX_DISTANCE ==50?

5

MAX_DISTANCE probably won't change.

#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

kevintutor, note the use of code tags below.
Quote this post to see the source or use the # button above the smileys to make a set of your own.
The tags keep code from being interpreted as html.

6

You have created MAX_DISTANCE with the code #define MAX_DISTANCE 200 That means rwo things. First, MAX_DISTANCE is not a variable in the memory of the program - it is just something the compiler knows. And second, because it is not a variable it can never change.

The variable that represents the distance that is measured by the ping sensor is called uS and it is a number of microseconds.

You probably want to create a new variable called (perhaps) distanceCM = uS/US_ROUNDTRIP_CM; and use that variable in the tests where you presently have MAX_DISTANCE.

...R

7

GoForSmoke:
kevintutor, note the use of code tags below.
Quote this post to see the source or use the # button above the smileys to make a set of your own.
The tags keep code from being interpreted as html.

@op, these things:

[code=myfile.h]
  //Some code
[/code]

Produces:

  //Some code