Preparing the Servos

The type of servos I used are called Standard Servos. These are able to rotate a maximum of about 175 degrees and provide more than enough range of motion for this project.

• Gently move the servo horn clockwise until it will not turn anymore and then do the same in the counter clockwise direction.
• Take note of your servos' approximate motion range. You will need to know this detail before permanently installing the servo onto the cardboard.
• Before mounting the servos onto the cardboard, you need to remove the servo horns. Using a Philips screw driver, remove the center screw holding the horn onto the servo and then pull the servo horn off to expose the spline. The spline is white colored part with gear teeth on the side that is exposed when the horn is removed.

Create the Mounting Surface

To anchor the servos, you will need a surface stronger than the felt material that the prop is made out of. The holes you will create are for the servo spline.

• Take some cardboard (or foamcore/styrofoam/etc) and cut out an outline to the body shape of your prop.
• Then using a Dremel or a drill, drill holes 0.25” in diameter near the pivot point of each limb.

For the sake of simplicity, I simply eye-balled the location for where the hole should go and started drilling. For better-looking results, you may want to do some measuring first.

Installing the Servos

• Install the servos from the backside of your project. The spline should stick out on the "front" side of the project so you can attach your prop and the rest of the servo should be in the back, hidden.
• Then, reinstall the servo horn back onto the servo.

This should hold the servo onto the cardboard. The servo spline may not poke all the way through the cardboard but that’s ok because the servo horn should still be able to connect to the spline.

Remember to take into account the servos angle of motion so that you get the maximum range of motion for your project. Spend some time making sure it can perform the motion you want before anchoring the servo down permanently. You will likely need to loosen or remove the horn again to apply glue.

• Once you have decided what position you want your servo in, glue it down. I marked the position I wanted first, with pencil, then glued so I knew exactly where to apply the glue.
• Do the same for the remainder of your servos. (See pictures for an example of how I glued mine.)

Moving the Limbs

Each servo horn is too short to move a limb on its own. You can use popsicle sticks, pipe cleaners, or other makeshift items and glue them onto the servo horn so that the servo can reach further. I didn’t have popsicle sticks unfortunately, because somebody decided to eat ALL of the popsicles in the freezer here at Parallax.

There are no hard and fast rules to the arts and crafts part of this project. I used aluminum parts from one of our crawler kits but you can also use any type of item that you think will do the job.

• Using your makeshift servo extender arms, connect the limbs to the servos with glue or by tying them down with string.

Add Some Sound to the Movements

To add sound to your project, you’re going to need a couple of items. You will need a micro sd card and a speaker such as the one we carry in on our webstore (listed in parts section). You will also need to know how to place a .wav file onto the card.

• If you have SimpleIDE installed, follow the directions provided in the Play WAV Files tutorial here [8] to load the wav file of your choice to your SD card.
• If you do not have SimpleIDE installed, you will need a microSD card/USB adapter you can plug into your computer to load in your wav file. See the tutorial above for filename limits and other restrictions.

Want to create or edit files of your own for use in this project? See our Sound Library [9] reference guide for help.

• Once you have your file on the sd card, test it by plugging your speaker into the Activity Board's audio jack and creating a small test program in Blockly using the AUDIO > Wav Files blocks.

For help using these blocks, see the Propeller BlocklyProp Block Reference [10] section.

If you only want your file to play for a limited amount of time then add a 10000 millisecond pause block after the WAV play file block or whatever amount of time you choose, then add a WAV stop block right after. If you would like your file to play until the end don’t add a WAV stop block.

Motion Activation

The PIR from the Animation Kit is a great way to motion-activate your new project. It is simple to program and effective during the day or at night.

• Familiarize yourself with this sensor by trying the quick-start code in the Propeller BlocklyProp Block Reference [11].
• Physically attach the PIR in a position where the lens faces the front of the prop so that people walking by can trigger it.

I plugged in my long jumper wires to the 3 pins on the sensor, then glued the black part of the cable connector to the backside of my project. If you are obscuring the pin connection markings, make sure you know which pins are for ground, power, and signal on your PIR before you glue it down or cover it in some way.

The Wiring

Now that the components are in place, it's time to wire it up.

• Mount your Activity Board WX to the back. If you want to re-use your Activity Board, find a non-permanent solution that works for your project.
• Mount your battery pack.

I used Servo Headers 14-17 for the arms and legs, and the other ends of the PIR jumper wires into PWR, GND, and P0.

• Follow the schematics below for proper connections and pin assignments according to my code.

Note: My code has a servo assigned for head motion, but I did not use it in my project. You will likely need to modify the code for your own purposes.I wanted to make the prop insert into the soil of someone’s front yard, so I glued a metal rod down the center of the prop so that it lends itself to insertion into the ground. You can use a stick or whatever item you see fit.

The key is not to make it too complicated. Simplicity is the best path for these kinds of projects because they are meant to be creative and fun. Use the pictures included in this project to make your project just like mine or to help make it your own.

Happy programming!