arduino_serial_servo.c

/*
 * NewSerialServo
 * --------------
 * Servo control from the Serial port
 *
 * ####
 * Modified by Adam Greig, Jun 2010, to just move the servo
 * to one position or the other on '.' or ',' input.
 * ####
 *
 * Alteration of the control interface to use < and > keys
 * to slew the servo horn left and right.  Works best with
 * the Linux/Mac terminal "screen" program.
 *
 * Created 10 December 2007
 * copyleft 2007 Brian D. Wendt
 * http://principialabs.com/
 *
 * Adapted from code by Tom Igoe
 * http://itp.nyu.edu/physcomp/Labs/Servo
 */

/** Adjust these values for your servo and setup, if necessary **/
int servoPin     =  2;    // control pin for servo motor
int minPulse     =  600;  // minimum servo position
int maxPulse     =  2400; // maximum servo position
int turnRate     =  100;  // servo turn rate increment (larger value, faster rate)
int refreshTime  =  20;   // time (ms) between pulses (50Hz)

/** The Arduino will calculate these values for you **/
int centerServo;         // center servo position
int pulseWidth;          // servo pulse width
int moveServo;           // raw user input
long lastPulse   = 0;    // recorded time (ms) of the last pulse


void setup() {
  pinMode(servoPin, OUTPUT);  // Set servo pin as an output pin
  //centerServo = maxPulse - ((maxPulse - minPulse)/2);
  centerServo = 1700;
  pulseWidth = centerServo;   // Give the servo a starting point (or it floats)
  Serial.begin(9600);
  //Serial.println("      Arduino Serial Servo Control");
  //Serial.println("Press < or > to move, spacebar to center");
  //Serial.println();
}

void loop() {
  // wait for serial input
  if (Serial.available() > 0) {
    // read the incoming byte:
    moveServo = Serial.read();

    // ASCII '<' is 44, ASCII '>' is 46 (comma and period, really)
    if (moveServo == 44) { pulseWidth = 1700; }
    if (moveServo == 46) { pulseWidth = 1900; }
    //if (moveServo == 32) { pulseWidth = centerServo; }

    // stop servo pulse at min and max
    if (pulseWidth > maxPulse) { pulseWidth = maxPulse; }
    if (pulseWidth < minPulse) { pulseWidth = minPulse; }

    // print pulseWidth back to the Serial Monitor (uncomment to debug)
    // Serial.print("Pulse Width: ");
    // Serial.print(pulseWidth);
    // Serial.println("us");   // microseconds
  }

  // pulse the servo every 20 ms (refreshTime) with current pulseWidth
  // this will hold the servo's position if unchanged, or move it if changed
  if (millis() - lastPulse >= refreshTime) {
    digitalWrite(servoPin, HIGH);   // start the pulse
    delayMicroseconds(pulseWidth);  // pulse width
    digitalWrite(servoPin, LOW);    // stop the pulse
    lastPulse = millis();           // save the time of the last pulse
  }
}

motion.conf

videodevice /dev/video0
locate on
webcam_port 8000
webcam_localhost on
snapshot_interval 1
snapshot_filename snapshot
ffmpeg_cap_new on
gap 2
on_event_start /usr/bin/python /home/adam/motion/shoot.py
on_event_end /usr/bin/python /home/adam/motion/stop.py
minimum_motion_frames 3
output_normal off
lightswitch 30
noise_tune off
noise_level 40
threshold_tune off
threshold 2000
height 640
width 480

shoot.py

# play a random start-up sound with mplayer, and then tell the arduino
# to fire the nerf turret for one second (~6 shots)
import serial, time, random, os

ser = serial.Serial('/dev/ttyUSB0', 9600)

filename = random.choice(os.listdir("/home/adam/motion/start/"))
os.system("mplayer /home/adam/motion/start/" + filename + " &")
time.sleep(1)

ser.write(".")
time.sleep(1)
ser.write(",")
ser.close()

stop.py

# play a random shutting-down sound with mplayer
import random, os

filename = random.choice(os.listdir("/home/adam/motion/stop/"))
os.system("mplayer /home/adam/motion/stop/" + filename)