Instructables
Picture of Twitter Controlled Pet Feeder
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A great project for busy pet owners. This Twitter-Controlled pet feeder automatically dispenses food in response to activity on your Twitter account. The project is controlled by an Arduino and uses the Arduino Ethernet shield to receive data from Twitter. I hacked this automatic Pet Feeder from Amazon to build this project, but you could easily modify your own motorized feeder to work.

Parts List:

(1x) Automatic Pet Feeder Amazon
(2x) 10K Ohm 1/4-Watt Carbon Film Resistor (1 package) Radioshack #271-1335
(1x) Arduino Ethernet Shield Radioshack #276-130
(4x) CdS Photoresistors 5 pack (1 package) Radioshack #276-1657
(1x) Grid-Style PC Board Radioshack #276-147
(2x) White Super-bright LED Indicator Radioshack #55050633
(1x) Male Header Pins 40 Position Jameco #160882
(4x) "D" Alkaline Batteries (1 package) Radioshack #23-865
(2x) 4.7K Ohm 1/4-Watt Carbon Film Resistor (1 package)
(2x) current limiting resistors, see the sample calculation below

from the specs of the LEDs I used:
"Continuous forward current: 30mA"
"Forward voltage: 3.6V"

using the following relationship:
V(volts) = I(amps) * R(ohms)
rearranged to:
R = V / I

we can calculate the resistance as follows:
voltage across resistor = 5V - 3.6V = 14V
1.4V / 0.03A = 47ohms

I used 100 ohm 1/4W 5% Carbon Film Resistors Radioshack #271-1311 so that the LEDs wouldn't be operating at their maximum ratings. Check the datasheet of the LEDs you use to calculate these values.

Additional Materials:
drill
Solder Radioshack #64-013
22 Gauge Wire Radioshack #278-1224

 
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Step 1: Open pet feeder

Picture of Open pet feeder
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Unscrew 8 screws from the base of the pet feeder and carefully lift the bottom panel of the feeder open.  There are some wires which permanently attach the bottom panel to the body, be careful not to put too much strain on them.

Step 2: Unscrew pcb

Picture of Unscrew pcb
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Remove six small screws from control pcb.  One of the screws is hidden under a small pcb on top of the main pcb.  Once all the screws are removed, the pcbs should easily lift off the plastic enclosure.
kolbolt2729 days ago
not trying to be rude but can't you just set the automatic feeder to idk automatically feed your dogs... but fun looking project
vetta7 months ago

Hi Amanda,

Could I ask you some questions in private?

Lover951 year ago
Hi Amanda, great project! I thought I would do this for my senior project at school. Instead of using photoresistors and leds, using a simple transistor with a 2.2K resistor on the base, connecting the emitter to the ground side of the button pad and the collector to the positive side of the button pad would be a more cost-effective and time sparing solution. Also, I would put in piece of code that would post a tweet after the feeding procedure was completed to prevent overfeeding. But thank you, great idea, and this instructable will certainly come in handy.
Dylon124 Lover9510 months ago
That's what I was thinking, why not some transistor, maybe because of the power flowing through it to control the pet feeder.
rgivs1 year ago
I have gotten to the step where you attached the Ground from the D Battery on the feeder to the PCB board. I must have put it on the wrong area as one of the LEDs is constantly lit. Do you have an exact spot to put it?

Also, do you have a part number for the Test Buttons? I can't find them. Great project though!!! I am almost done with mine.
Is the USB cable just for the initial program load? You can disconnect it after that, right?
sciencetor22 years ago
Definitely a cool project, but 1 question, why use photo resistors and LEDs in stead of just straight transistors or some form of switching circuit? Seems like a bit of a roundabout solution
JoeMurphy2 years ago
I would love to see more of an explanation of how the arduino code works. Great project!
This is a nifty bit of work......however......I would NEVER be too busy to get home to your dog! I love English Bull Terrriers. Sadly ours died last year but we are now ready to invite another Bully into our home.

If it isn't an English Bull Terrier......it's just a dog!

Apologies to owners of other breeds, I'm sure you feel just as passionate about yours.
TobbaBK2 years ago
Great project! But what prevents the dog from shredding it into pieces? :P
inkfzz2 years ago
just dont loose your phone or your dog might famish:-)
rrkrose2 years ago
This is too cool! I am really bad with electronics but I will have to learn the basics so I will be able to make this soon.
leeski2 years ago
that is one awesome project! My dog Buckley would love this.
i have been wanting to do something like this