Introduction: Interactive Cookie Monster Plush Toy

Make an adorable, lovable, cuddle-able Cookie Monster toy who loves cookies! His eyes light up blue when you give him a cookie, but red if you give him a carrot. Shaker motors vibrate in his stomach if Cookie Monster hasn't had something to eat for a while.

This project was created for Things That Think 2012, a class at the University of Colorado 

Step 1: Cut Out Pattern

Using the adobe pattern files  cut out all of the parts for Cookie Monster. Make sure you use furry blue fabric for the body, head, hands and legs. Use white felt for the eyes and black felt for the inside of the mouth.

Step 2: Feet/Legs

Sew the top and the bottom of the foot together using a sewing machine. The leg looks better if you sew them inside out and then flip them fuzzy-side-out. This hides the seem on the inside of the toy.  Next, fold the leg into a cylinder and sew the edges together. Now sew the bottom of the leg into the hole in the foot and stuff it. Do not sew the top of the legs, this is where they attach to the body. Repeat these steps for the other leg.

Step 3: Arms

Sew the two halves of the arms together inside out, and then flip them fuzzy-side-out to hide the seam. Do not sew the end of the arm that connects to the body. Stuff the arm. Repeat these steps for the other arm.

Step 4: Body

Marking off a 1 inch section along his side for Velcro goes (giving you access to his innards), sew the rest of the body together making sure not to sew over the section you marked off. Again, you want to sew it so together with the fuzzy sides touching and then flip it inside out to hide the seam. Now that the body is fuzzy side out, you can sew or glue the Velcro in place. Then sew the legs and arms onto the body and stuff with polyester stuffing.

Step 5: Head

To create the mouth, cut out black felt in the shape and size of the mouth opening. Next, cut out black felt rectangles, one that fits across the top of the mouth, and one that goes along the bottom curve. Mark off a section on the bottom of his head under his mouth, which will not be sewn so that wires can be fed through the bottom of his head. Sew his head together leaving the marked section for his neck un-sewn. 

Step 6: Cookie and Carrot

Cookie: cut out two circles (roughly 3.5 inches in diameter) from tan felt. Cut out several small, irregular circles from dark brown felt for the chocolate chips. Glue the chocolate chips onto the cookie. Sew the two cookie halves together, leaving a half-inch long section for Velcro. This opening is so the RFID chip can be taken in and out. Stuff the cookie and Velcro it shut. 

Carrot: cut out a triangle with a round bottom from orange felt, and three small green rectangle which will become the stem.  Sew the straight edges of the orange triangle together, leaving about an inch un-sewn, attach the Velcro access to the un-sewn area.  Sew the green rectangle to create small cylinders.  Stuff the carrot with polyester filling.  To Finish the carrot place the stem around the open top of the carrot.  Sew around the top of the carrot using a cross stitch.  When you have sewn around the top of the carrot one full time pull the thread tight.  This should close the top of the carrot, pulling the stems together as well.   

Step 7: Eyes

Laser cut out two 2.5 inch diameter circles out of white felt. Laser cut a 0.8 inch hole in the middle of the white felt circles. Cut out a section of black mesh and sew it over the back of the 0.8 inch hole. Sew the two white felt pieces together, leaving an opening at the bottom. Use a hole-punch to make a hole in the back of the eye. This is where the LED wires will be fed though. Repeat these steps for the other eye.

Step 8: Put LED's in the Eyes

Get two RGB LEDs. Solder long wires onto the R, G, B, and ground pins. Be sure to label the wires so you don;t get them mixed up while feeding them through Cookie Monsters body.  Place the LED in the eye so it will show through the pupil mesh.  Feed the LED wires through the hole punched earlier. Repeat for the other eye.

Step 9: Sew Eyes on Head and Sew Head on Body

Feed the wires from the LEDs though the face about an inch from the top, this will dictate the eyes placement on the face. You may have to cut a small hole in the head in order to feed the wires through.  Sew the eyes onto the face so that it looks good. Then feed the wires through the bottom of the head and though the top of the body. Again, the wire placement will dictate the placement of the head on the body, and you may have to cut a small hole.  Sew the head onto the body. Finally, bring the wires outside of the body through the Velcro opening in the side of the body.

Step 10: LED/RFID/Shake Motor Wiring to the Arduino

Wire up the RFID components according to the instructions on the following website:

Place the LED wires into the appropriate pins, and mark which wire goes where.

Step 11: Add Shaker Motors

Wire up two vibrator motors and put each in a plastic bag, this will keep the motors from getting tangled in the polyester filling.

Step 12: Put Electronics Inside Body

Put the Arduino and wiring into a box of some kind to keep things clean and protected.  We made a simple box using a laser cutter and acrylic. Put the box into Cookie Monster's stomach through the Velcro opening.  Be sure to place polyester filling around the box so you cant feel it, but keep the RFID and vibrator motors close to the surface.  We found that although the RFID reader we used advertised a range of 10+ cm, the actual range is more like 1 cm, so it will not work if it is buried inside the stomach.

Step 13: Arduino Code

Attached to this step is the code to run the RFID, LED's, and vibrator motors.  Change the pin definitions in the arduino sketch to match your wiring for the LEDs and motors, then upload the sketch to the board.  Run the code on the Arduino and watch Cookie monster's eyes light up and feel his tummy rumble!

Step 14: Future Improvements

Here are some improvements you might want to make:
1) Add more objects for Cookie Monster to respond to
2) Add force or tilt sensors Cookie Monster can use to interact with
3) Add a speaker so Cookie Monster can sing "C is for Cookie"
4) Add an internal power supply so your kids can take Cookie Monster anywhere

If you have any other ideas for improvements please post them in the "Comments" section.

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