This robotic fridge cat will remind you not to skip meals

If you work from home, you know about the food problem. Some of us forget to eat, some of us over-snack. This tiny fridge magnet will remind you what your stomach is already telling you — when it’s time to eat, and when you’re probably already full.

Choose when and how many times you want to eat each day, and this kitty will make a hungry face to remind you it’s time. The more you open the fridge between mealtimes, though, the fuller (and more annoyed) it gets. So if you’re not happy that you’re munching on leftover stuffing after already eating three helpings of turkey and mashed potatoes, neither is kitty.

Plus, the fridge kitty is flexible for any kind of eating schedule. You can configure your own ideal snack habits in the firmware, and even have it text you to remind you to eat through IFTTT.

Building your own is easy! Instructions below. If you have questions about the build or are looking for more hacks, find me on Twitter or check out hackpretty.com.

Materials

• Particle Photon
• Microservo (with 3.3 V operating voltage)
• Gyroscope (I used this accelerometer/gyroscope)
• M-F jumper wires
• F-F jumper wires
• Plastic spur gears, 1 ⅛ in diameter
• Screws to fit your spur gears (I used 10mm M2 screws)
• Screws for your servo, these usually come in a bag with your servo
• Screwdriver with attachment for the above, and a small Phillips head attachment for the microservo screws
• Bolts to fit your screws
• Cardboard
• Tape or hot glue
• Magnets (I used ⅛ in tall neodymium magnets with a ½ in diameter)
• This 3D printed enclosure

Build It!

Start printing the enclosure! This will take a while, but in the end you should have these parts:

Set up your photon and check out this code. (For a comprehensive tutorial on using the Photon, check out the Particle Docs.) Read through the firmware and change any settings you need to — namely the settings for time zone and meal times. Then, save and flash the code to your Photon. If it’s your first time working with the Photon, you may be downloading firmware updates for a few minutes.

Line up your kitty’s right eye by threading the screw through the gear, the cat’s right eye hole, and the flat-bottomed offset. Secure it using a bolt on the other side. Make sure it loose enough that it can still rotate.

Add F-F wires to your gyro. Attach your gyro to the kitty’s head, inside on the right side.

Press the conical offset onto the top of the servo.

Screw in the servo so that the head of the servo fits in the cat’s left eye.

Attach a gear to the servo and secure it tightly, sandwiching the conical offset in between the servo and the gear. It should be tight enough that it does not spin on its own. Slide it in so that the teeth of the left servo interlock in the free-spinning right servo. The left servo/gear combination will drive the gear on the right side.

Add your Photon. Plug in the servo and gyro to your Photon as follows:

Gyro Photon

VCC 3V3

GND GND

SDA D1

SCL D0

INT D2

Servo Photon

GND GND

PWR VIN

DATA A4

Tuck your Photon and wires into the back of the magnet. Thread the USB cable out of the magnet through the cat’s “legs.” Put a little tape over the Photon to hold it in and protect your fridge from scratches.

Attach the magnets to the magnet impressions using a little hot glue.

Turn it on once to make sure the eyebrows align to the “neutral” position, then tape black paper onto the gears to represent eyebrows.

Stick it on your fridge. Go kitty go!

Getting Text Reminders

You can have your kitty email or text you when you need to eat by hooking it up to IFTTT. Set up the Particle channel and select “New Event Published” as your trigger. Find your Photon and make sure you select the kitty’s “meal” event as your trigger. I like to connect it up to SMS for output, but Gmail and other forms of communication are also options! This tutorial shows a very similar process. Make sure you use the “meal” event instead of the “button2” event.

Tracking Your Snack Habits

Every time you open the fridge door outside of meal hours, your Particle device publishes a private event called `snack`. You can track this published event a bunch of ways, but two simple ones are:

Use Librato: Follow this tutorial but with “snack” as your event instead of “temp”

Make a Google spreadsheet on IFTTT, with the trigger being a Particle published event. You can follow this tutorial, but with “snack” instead of “temperature.”