Thursday 31 October 2013

Halloween Pumpkin and Raspberry Pi

I wanted to make my son a hi-tech Halloween Pumpkin which would light up and make scary noises when a unsuspecting zombie, witch or alien walked up to the door, so out came a raspberry pi, PIR sensor, soldering iron and a load of led's.

2 red led's went into the pumpkin's eyes, 2 large super bright white led's went into the middle and the PIR sensor was bodged into his nose, all connected together with some dodgy wiring.  I pushed the raspberry pi and a x-mini speaker into the middle and all that was needed was some software.

Me and Mrs O'Hanlon recorded some scary sounds using the voice recorded on my phone which I then copied onto the Pi.

I started with the program from raspberry pi spy's article on cheap PIR sensors and the raspberry pi as the basis for my software to which I added in some code to flash the red led's when the PIR wasn't triggered and turn them on and play a random sound when it was.

Anyway, my boy absolutely hated it, it made him cry :( but I stuck it outside the front of the house and the local children loved it.

You can also find the code on github,

import gpioRap as gpioRap
import RPi.GPIO as GPIO
import subprocess
import time
import random

#Create GpioRap class using BCM pin numbers
gpioRapper = gpioRap.GpioRap(GPIO.BCM)

#Create an LED, which should be attached to pin 17
white1 = gpioRapper.createLED(4)
white2 = gpioRapper.createLED(17)
red1 = gpioRapper.createLED(21)
red2 = gpioRapper.createLED(22)

# Define GPIO to use on Pi

# Set pir pin as input


    Current_State  = 0
    Previous_State = 0

    # Loop until PIR output is 0
    while GPIO.input(GPIO_PIR)==1:
        Current_State  = 0

    redeyecounter = 0

    #Loop until exception (ctrl c)
    while True:
        # Read PIR state
        Current_State = GPIO.input(GPIO_PIR)
        if Current_State==1 and Previous_State==0:
            # PIR is triggered
            print "  Motion detected!"
            # turn on red and white lights
            # play random sound
            soundno = random.randint(1,6)
  ["mplayer","/home/pi/dev/pumpkin/"+str(soundno)+".m4a"], shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

            # Record previous state
        elif Current_State==0 and Previous_State==1:
            # PIR has returned to ready state
            print "  Ready"
            # turn off red and white lights
        elif Current_State==0 and Previous_State==0:
            #in steady state, incremenet flash red eye state
        #every 5 seconds (ish) of steady state, flash red eyes
        if redeyecounter == 500:
            redeyecounter = 0
            for count in range(0,3):

        # Wait for 10 milliseconds

except KeyboardInterrupt:
    print "Stopped"


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