This is a new version of the evil spider. I’ve replaced the LED in the head with two smaller LEDs in the eyes. This way the brightening is easier to see.
Some close-up photos are at the end of this post – if you fear spiders, scroll slowly down to the image with breadboard 😉
(BTW: at 00:10 you can see Daniel)
The source code is rather simple:
/* Spider - sketch for spider control
*
* 12. Apr 2012 danimath created
* 02. May 2012 danimath added blinking
*
**********************************************************************/
byte usPin = 8; // ultrasound pin
unsigned long usDuration; // ultrasound duration
unsigned int cm; // roughly calculated cm
byte ledPin = 3; // LED pin
int brightness; // LED brightness
int min_threshold = 15 ; // treshold for blinking LED
const int max_threshold = 100; // treshold for brightning LED
const int mesDelay = 250; // msec between measurements
//#define DEBUG
/* setup - initialise things
*
**********************************************************************/
void setup ()
{
#ifdef DEBUG
Serial.begin (9600);
#endif
analogWrite (ledPin, 255);
usDuration = getDist (); // warm up measurement
delay (2500);
analogWrite (ledPin, 0);
}
/* loop - the ever lasting loop
*
**********************************************************************/
void loop ()
{
usDuration = getDist ();
cm = usDuration / 58; // int is enough for this
#ifdef DEBUG
Serial.print ("usDuration: ");
Serial.println (usDuration);
#endif
if (cm < min_threshold)
{
if (brightness == 0)
brightness = 255;
else
brightness = 00;
}
else if (cm < max_threshold)
brightness = map (cm, 0, max_threshold, 200, 0);
else
brightness = 0;
analogWrite (ledPin, brightness);
delay (mesDelay);
}
/* getDist - gets the distance from SRF05
*
* return value: micro seconds
*
**********************************************************************/
unsigned long getDist ()
{
unsigned long retVal;
pinMode (usPin, OUTPUT);
digitalWrite (usPin, LOW);
delayMicroseconds (2);
digitalWrite (usPin, HIGH);
delayMicroseconds (10);
digitalWrite (usPin, HIGH);
pinMode (usPin, INPUT);
retVal = pulseIn (usPin, HIGH);
#ifdef DEBUG
Serial.print (retVal);
Serial.print (", ");
Serial.print (retVal / 58.0);
Serial.println (" cm");
#endif
return (retVal);
}
The hardware is just as simple as the software. This image is created with Fritzing. Of course I didn’t use a breadboard in the final construction.
As promised here are the close-ups:
(Repost from my old blog, 2012-05-03)
