Squirt is a motion activated water cannon using Arduino.
This was designed for use in the garden but as it’s winter we tested it in the bathroom. It works!
[mom_video id=’zyzPr9R7RzI’]
True motion tracking is expensive and complicated so this system activates when the victim moves into range and randomises the position of the cannon and the firing time within a limited area. The sometimes fickle readings from the PIR sensor just adds to the cannon’s randomness, and therefore the fun.
This is my first Arduino project.
Step 1: Parts
Windscreen washer pump
PIR motion detector
servo motor
TIP 120 npn transistor
10k resistor
1N4004 diode
12v rechargeable NiMH battery
on/off switch
watertight box to house the workings
Watertight reservoir
Various length 22 awg jumper leads
Soft tubing
Short length of pipe
Breadboard
Step 2: The Circuit
The PIR command wire goes to Digital pin 5 on the arduino and its positive wire goes to 3v pin and ground to ground.
Servo control wire is on pin10.
Pump is on pin 8 via the transistor 9which is protected by the diode).
The battery is a NiMH 12v connected to Vin pin via an on/off switch.
The battery, breadboard and arduino are housed inside a watertight sandwich box.
Mounted on top is the PIR which is inside a length of plastic tube to restrict its field of vision to directly ahead.
The servo is mounted on top of the water reservoir- in this case a plastic tub from the kitchen supplies department of the local supermarket. The pump is fitted near the bottom of the tub with its outlet connected to a flexible pipe from an aquarium supply shop and (rather messily) attached to the sevo arm with a lump of blu-tac.
Step 3: The Code
#include <ServoTimer1.h>
/*
- “Squirt”. Jonathan Robson Feb 2009.
*
- A PIR activates a servo & pump. Servo moves its arm to a random position between 60 and
- 120 degrees, fires a pump for half second and returns to center (90 degrees). Cycle repeats
- 3 times at random intervals between half and 3 seconds then waits to detect further movement.
- Circuit based on http://itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads
- PIR code adapted from http://www.liquidware.org/view.php?id=63
- Random code adapted from www.arduino.cc/en/Tutorial/Blink & www.arduino.cc/en/Reference/Random
- Servo code adapted from http://www.ladyada.net/make/mshield/use.html
*/
int transistorPin = 8; // transistor base connected to pin 8
ServoTimer1 servo1; // defines the servo
long randOff = 0; // Initialise a variable for the OFF time between shots
long randNumber; // Initialise a variable for servo position angle and delay between shots
void setup()
{
servo1.attach(10); //servo on pin 10
pinMode(8, OUTPUT); // set the transistor pin 8 as output to pump
pinMode(5, INPUT); // set the PIR pin 5 as input
digitalWrite(8, LOW); // defines LOW as movement
randomSeed (analogRead (0)); // randomize
}
int pinin = 0;
long countint = 0;
void loop()
{
pinin = digitalRead(5); // reads the PIR sensor
while (pinin == 0)
{
pinin = digitalRead(5);
}
servo1.write(90); //sets servo to center
randOff = random (500, 3000); // generate OFF time between 1/2 and 3 seconds
delay(randOff); // waits for a random time while OFF
servo1.write(randNumber = random(60, 120)); // servo to random position within 30 degrees of center
delay(400); //gives servo time to get there
digitalWrite(transistorPin, HIGH); // turns pump on
delay(500); //fires pump for 1/2 second
digitalWrite(transistorPin, LOW); // turns pump off
servo1.write(90); // moves servo back to center
randOff = random (500, 3000); // generate new OFF time between 1/2 and 3 seconds and repeat
delay(randOff);
servo1.write(randNumber = random(60, 120));
delay(400);
digitalWrite(transistorPin, HIGH);
delay(500);
digitalWrite(transistorPin, LOW);
servo1.write(90);
randOff = random (500, 3000); // generate OFF time between 1/2 and 3 seconds and repeat
delay(randOff);
servo1.write(randNumber = random(60, 120));
delay(400);
digitalWrite(transistorPin, HIGH);
delay(500);
digitalWrite(transistorPin, LOW);
servo1.write(90);
delay(3000); // gives the PIR time to “settle” before reading again
}
