Picture of Arduino-Powered Pumpkin
This Halloween project uses an Arduino with a proximity sensor and a bunch of LEDs to greet guests at your doorstep.

Step 1: Program the Arduino and hook it up

Picture of Program the Arduino and hook it up
The code for this is based on an example from Tom Igoe's Making Things Talk. It's pretty simple: the Arduino monitors a Sharp GP2D12 Infrared ranger, and if it detects movement nearby, it turns all the LEDs up to maximum brightness. While it's waiting for someone to step close to it, the Arduino flickers the lights.

Pins 9, 10, and 11 go to LEDs that are shown in the next step. Analog pin 0 goes to the proximity sensor. Power and ground go to the breadboard that houses the LEDs and the sensor.

The attached file, Pumpkin.pde, contains the Arduino code you need to upload to your Arduino.
geeklord6 years ago
cool. So does the rangefinder have an analog output of a varying voltage?
i think thats right
rolandl6 years ago
Hook up 12 LEDs to the 12 IO pins. Control them from the keyboard of your linux system, or write a script to turn them on/off in some pattern. Use cron or similar to change the script periodically. See http://user.cavenet.com/rolandl and get the package, SMS1.tgz. Now with GUI via xdialog command.
cr0ybot7 years ago
Added to Arduino Group! ;D
flio1917 years ago
a pathway with these on either side, lined up (would essentially be a lot of work, but) would be really cool! The lights would turn on as you pass them!
hey thats cool! and if it probably saves alot of energy too cause its off when no ones near it. good idea
Hawaii000007 years ago
How about you make millions of these put them around youe door and wire them to your doorbell so that when it i rung they all turn on and your surrounded but glowing jack-o-lanterns about to eat you alive!!!!! Alright forget the eat you alive business.