Kitty Twitty Cat Toy

By Mark de Vinck
Category: Arduino, Home
Time Required: 1 day
Difficulty: Moderate

About 2 months ago, after years of begging and pleading from my family, I reluctantly agreed to get another cat from the local shelter. We already have a menagerie of beasts that share our home, but for some reason they felt we needed another.

I admit, I do like our new addition to the family. Chester is a spunky little stray who’s always looking for fun. Even if it means knocking a few things off my desk as I write this article. The only problem is, when my wife goes in to work, she misses her new cat and always wants to know his whereabouts.

She used to ask me for updates, but after a while I realized that I needed to make something that would take me out of the loop, and let the cat communicate with my wife directly via twitter.com. I needed a Twittering cat toy. And that’s how Kitty Twitty came to fruition, after some basic soldering and crafting with just a few parts.

Parts
/
Tools

Arduino Duemilanove (1) item #MKSP4 from the Maker Shed (http://makershed.com)
Arduino Ethernet Shield (1) Maker Shed #MKSP7
Power supply, 9-volt (1) Maker Shed #MKSF3. Or use a 9V battery with a center-positive 5.5mm×2.1mm barrel connector, especially if your cat chews on wires.
Enclosure (1) This can be almost anything, as long as the Arduino and Ethernet Shield fit inside. Also, since your cat will be playing with it, no glass or toxic paints, and the heavier the better. I used a $6 wooden box from a local craft store.
LEDs, 1 green, 1 blue (2)
Resistor, 10kΩ (1)
resistors, 220Ω (2) or other value matched to lighting your LEDs with 5V DC
LED holders (2)
Switch, SPST (1) I used a sub-mini toggle, RadioShack part #275-0612.
Ethernet cable (1)
Wire, solid-core, 22-gauge, 2'-3', various colors (1)
Solder, rosin-core (1)
Heat-shrink tubing, 1/8' diameter (1)
Craft glue, non-toxic (1)
Paint, non-toxic (1)
Paper, various colors (1)
Glue stick (1)
Sealer, non-toxic (1) (optional)
Guitar E string, or similar steel wire (1)
Wall anchor, hollow, medium duty, metal #6-32×1½' (1) or similar, from a hardware store
Computer, running Arduino software (1) free download at http://arduino.cc
USB A-B cable (1) for programming the Arduino. Borrow one from your printer.

Binder clips
Drill My LED holders and switch needed 5/8" holes; yours may vary.
Eraser
Fume extractor but highly recommended, for your respiratory health when soldering. To make your own, see MAKE Volume 19, page 123.
MAKE: Warranty Voider Leatherman "Squirt" E4 #MKWVE4 from the Maker Shed. Or you can use standard cutting pliers and needlenose pliers.
Paintbrushes
Pencil
Scissors
Screwdriver
Soldering iron

Steps

Step #1: Drill and paint the enclosure.

Chester doesn’t get too aggressive with the Kitty Twitty, but if he ever does, I’ll add some weight to the enclosure to help keep it upright.
Decide where to drill the hole for the power and Ethernet cables. Attach the Ethernet shield on top of the Arduino and place them in the box to see where they fit best. Mark the location of the hole with a pencil on the outside of the box
Use a ½" spade bit to drill the hole, and go slow to minimize splintering. Once the hole is drilled, give it a quick test-fit. Does it fit? Yes? Good!

Conclusion

Operation

This is really easy. Simply plug in the power supply and Ethernet cable, and flip the switch. The green power LED should come on, and in a few seconds, the blue network status LED, too. The code tweets an “Up and Running” message to let you know everything is OK. You can plug a USB cable into the Arduino and listen in on the serial port for some debugging.

Every time the wire makes a connection, you’ll see a new tweet! That’s it!

Variations

You can modify this project to make almost anything send a tweet. It’s a cat toy, but there’s no reason it can’t be converted into a Twittering dog toy, or even a Twittering bird perch. Just substitute a different kind of switch sensor for the bird-on-a-wire. Make a Twittering burglar alarm? Easy! Doggie door? Sure! Twittering fish? Now that’s a challenge!

Also, you can add additional switches or sensors, connect them to as-yet-unused pins on the Arduino, and write some code to handle them. Think about adding a servo to make some random rumbles, or a speaker to simulate a bird. That should keep your cat’s interest!

This project is still evolving, and I need to add more parts and experiment with them before I settle on the final Twittering toy. By the time you read this, I hope to have modifications that check whether your cat is sleeping or needs food, via pressure-sensitive piezos under its bed and food bowl. I also plan to add a speaker or small motor to get the cat’s attention. See http://makezine.com/22/kittytwitty to learn more about these modifications.