Ever wanted a low maintenance little 4 legged friend? In this article we will show you how to create your own little robot to decorate and love. 

Materials 

• Small rechargeable battery pack (dimensions of the smallest face should be less than 6cm *3cm)
• 3cm thick foam board
• Flute board
• 4 servo motors
• 4 metal split pins
• Coloured paper for decorating 
  

 Blocks

Power Station	WiFi/Bluetooth	Motor Driver

 Tools

• Box cutter
• Scissors
• Glue
• Hot glue gun + hot glue

Method

1. Cut an 8cm * 8cm square from your 3cm thick foam using the box cutter. 
   
2. Cut a hole in the centre of your block to fit your battery pack using the box cutter. Cut the hole so that the battery fits snug in the hole. 
   
3. Mark out the size of a servo on the corner of one. Use the box cutter to cut a hole. Check that the servo fits in the hole you've just cut. 
   
4. Do the same for each of the other four corners. Make sure that the orientation of the servos matches the image shown below. 
   
5. Referencing the image from step 4 for the positioning of each of the servos, glue each servo in using hot glue. 
   
6. With the battery pack inserted your platform should looks something like this. Select one of the faces to be your front. The servos should rotate parallel to the front and back of your robot. 
   
7. In the front of your platform insert four metal split pins. Space them so that the bottom of the Power Station Block's magnets align with the pins. 
   
8. Magnetically mount the Power Station Block to the Split pins. Also plug in your battery to the input port of the block. 
   
9. Add your Wifi/Bluetooth block and Motor Driver Block. 
   
10. Plug in each of the servos following the images below. The cables have been wrapped around the battery to reduce tangling. 
    

    Connect front two servos
    Connect Back to servos

    With all your wires wrapped and connected to the Motor Driver block you should have something like the image below. 
    

    Motor Driver Port	Servo Position
    0	Front Right
    3	Front Left
    2	Back right
    1	Back Left

    
11. Connect to your stack and configure the Motor Driver Block in servo mode as per this tutorial. 
12. In the Motor Driver Logic Maker create the logic below to calibrate all servos to 90 degrees. 
          
13. With the servos in the 90 degree position, attach each servo horn facing directly downward. See the image below as reference. 
    
14. Next we will be creating the legs. Cut a long strip of flute board 4 holes wide.
        
15. Cut the strips into four 3cm long segments.
    
16. Round the corners on one side of each of the four flute board segments. 
    
17. Slide the servo horn into the holes of the flute board. The fit should be quite tight, allowing it to be held on with friction. If you find that it does slide off, attach it with a small dab of hot glue.
18. Repeat for all four legs 
    

Your robot's body is now finished. All you need is to give it some brains to learn how to walk. 

Logic

To create the walking motion of your robot we will be switching between two different poses. To achieve the forward motion you will need to have diagonal legs moving the same direction. The front two legs rotate 90 degrees, and the back legs rotate the full 180 degrees. By giving the back legs the full 180 degree rotation it allows for greater push forward. It will still work with all legs rotating only the 90, but your robot will move at a slower pace. 

NOTE: Due to the way we've placed in the servos some will rotate from 90 to 180, whereas others will need to rotate 90 to 0. This is because when we placed them in they were flipped. 

By copying the logic above you should get motion similar to the image below. Try changing the angles to see how it affects the robot's movement. 

Decoration

It's up to you what you want to make your little four legged friend into. I've decided to make it into a little bulbasaur. 

To make the bulb on his back I followed this origami youtube tutorial. Once I glued the shell to stay together I cut the bottom out and placed it over the battery. To get it to stay more permanently I used some blu tac to secure it. 

For the face and legs I just sketched out a general shape on scrap paper. I then traced and cut out the shapes from coloured paper and attached it to the body with some hot glue/blu tac. 

Tadaaa~ Now you have a little walking friend to play with!