I teach a class called Maker Robotics at International School Manila. This is an introductory project that I use with high school students to teach them about using Arduino and creating circuits.
Step 1: Raw Materials Needed
I like giving people a block with several holes drilled into it. This allows for putting LEDs and servos in a variety of positions. A couple cheap servo motors work great for movement and are easily powered by the Arduino Uno. For the LEDs, I solder 330 ohm resistors directly to the anode (long positive) leg. Crayola Model Magic is pretty great for going on easily and then drying after a day or two into something fairly permanent. Some sort of thin crafty-type wire works well as a skeleton for supporting the clay.
Step 2: Design and Assemble
I drew a sketch first of what I wanted my MonsterBot to look like. Then I used hot glue and zipties to get the LEDs and servos into position (after testing them). I prefer to put the negative (cathode, short) legs of the LEDs near each other before gluing into position.
Step 3: Create the Circuit
Solder the negative legs of the LEDs together and attach to a jump cable. I covered the positive legs and resistors with heat shrink. I then plugged the the LEDs into two output pins on the arduino. For the two servos I decided to do some splicing of wires to avoid using a breadboard. After cutting and stripping, solder the two grounds (brown) together and to a jump cable. Connect to ground. Solder the two 5 Volt cables (orange) together and to a jump cable. Attach to 5 Volts. For each yellow cable of the servos, solder to individual jump cables and attach to two separate output pins. Use heat shrink to protect all these splices.
Step 4: Upload Code and Test the Robot
Here is a simple code to run two LEDs and two servos.
Attach the plastic lever arms that came with your servos onto the little servo rotor. Then test the code to see if they go to positions that you want. You may want to use the little screws that came with as well to screw the plastic into the rotor.
Now you can use some thin wire that can be bent easily to make a skeleton to support the clay.
Step 5: Add Clay and Character
Then I added the Model Magic clay and adjusted code to get a speed and position of arms that I really wanted. Don't bury the servos in clay, as you may need to replace one if it craps out.
I will then power this with a 9V DC cord. I hope to attach a springy doorbell switch so that it is off 99% of the time, but then I can turn it on for showing off the monstrosity to anyone lucky enough to be stopping by.