Activity Board 2: Spastic CP Board

Chris Byers
Yianni Doropoulos
Rebecca Forbes
Hannah Ross
Andrew Smith


The goal of this project is to design an activity board for a six-year-old child with spastic cerebral palsy. The child, Jude, is very intuitive but has a limited attention span. He is right-handed and loves taking things apart but often has trouble reassembling them. Jude has very limited mobility and struggles with many simple motions. This board will allow Jude to both have fun and practice skills he will need in day-to-day life.


This interactive board is designed to aid Jude in developing better motor control skills through various mechanical activities. Jude uses only his right arm and moves it in a counter-clockwise, circular motion. Due to his cerebral palsy, he tends to have jerky, uncontrolled motions. He holds his hand with his thumb and index finger turned downward and uses only these two fingers in a pinching motion to perform day-to-day tasks. Jude spends most of his time in a sitting/standing support chair with a small, attached table. He tends to accidentally knock off objects placed on his table. Given the opportunity, Jude will take apart anything placed in front of him. This board must be designed with all of these conditions taken into consideration while still providing entertaining, challenging, and physically rewarding activities.

Design Specifications

The activity board must be able to mount on various different surfaces. It is designed to be mounted primarily on the table surface of Jude's support chair. It can be moved from surface to surface but, due to Jude's spastic motions, the board must be temporarily secured to the surface in front of him. It needs to be approximately 20" x 24" and as interactive as possible, with many mechanical systems and cause-and-effect instances. The board must allow plenty of space for Jude's hands and broad, circular motions, and the activities should be designed so that Jude can complete them using only his right hand. The board should be composed of a material that does not pose any safety problems if the board is accidentally bumped into or knocked over. Any additional pieces, such as pegs, rings, gears, and magnets must not be easily knocked off the surface. Additionally, the board needs to be durable and lightweight. It will be mounted on the front of Jude's chair support and needs to be light enough so that it will not cause any tipping.

  • Specification Overview
    • Adaptable Mounting System
    • Stability when Mounted
    • Widespread Activity Space for Ease of Use
    • Lightweight and Durable Design
    • Highly Interactive Set of Activities

Preliminary Design Concepts

The designs all consist of the same basic concept of a 3-dimensional board/box. The board/box will be composed of either plexi-glass or wood, or a combination of the two, and will be mountable on either an independent surface or a specially-designed, wheeled table. Activities include a crank and gear mechanism, a rope and pulley mechanism, and several different activities with pegs, magnets, and clamps.

Board Concept 1

The first design concept consists of a open 24" x 24" box with two hinged sides that can raise and lower depending on the activity. The box will have a rubberized bottom for stability and will be separated into layers by a sheet of plexi-glass. The bottom layer, which will not be accessible by Jude, will contain all of the working parts of the mechanisms, such as gears, belts, and any electronic devices. It will also be used for mounting pegs, magnetic plates, etc. The top layer will contain all of the input devices, such as cranks and switches. Because the plexi-glass is transparent, Jude will be able to input motion and observe the effects.
  • Concept Overview
    • Hinged Sides for More Space
    • Rubberized Bottom for More Stability
    • Plexi-Glass Casing
    • Wooden Frame
    • Straps to Secure the Board to Tray

Board Concept 2


The second design concept differs from the first primarily in the way it is mounted. This design involves a custom-built, rolling stand. The board would be mounted permanently to the stand. The stand would have adjustable legs.

  • Concept Overview
    • Broader Wheel-Base than Board
    • Locking Casters for Wheels
    • Plexiglas Casing
    • Wooden Frame
    • Relatively Mobile

Board Concept 3


The third design, which could use either of the above two mounting ideas, differs from the others in its shape. Instead of being a box, this design would be a rectangular board with rounded corners. It would not have sides and would consist of one layer of Plexiglas. The top would be completely open, and the board would mount to surfaces with clamps. The board will have a wooden border that comes a little above the Plexiglas in order to help contain the pieces from the activities.

  • Concept Overview
    • Rounded Corners
    • Mounting Clamps
    • Rubberized Bottom
    • Wooden Frame
    • Plexiglas Case

Preliminary Activity Concepts

In more detail, the activities consist of:

1) A crank on the top layer that can be turned by Jude and connects to a shaft in the bottom layer. The shaft will have a gear mounted on it that meshes with another gear on another nearby shaft. This system will continue, using both pulleys and gears, and will activate a treasure chest style reward system via a mechanism similar to the way a car jack works.

2) A pulley system that wraps around the perimeter of the box and activates a jack-in-the-box type mechanism.

3) An activity that involves placing differently-shaped pegs into matching holes in the Plexiglas layer. Upon contact, the pegs will either light up or activate nearby lights.

4) A wire track that he can guide rings along on the top layer.

Preliminary Concept Evaluation

In all likelihood, the final design will incorporate features from each of the designs. The final board concept, at this point, will comprise of the adjustable legs with locking casters, an individual table element, straps to attach the board to the supplied table, a rubberized coating on the bottom of the board, a wooden frame, and a Plexiglas case. Activities that Jude can engage in include a crank-and-gear system will raise a hidden box, a pulley system that operates a jack-in-a-box, interactive light-up pegs, and a guided wire track to exercise a wide range of Jude's motion.

  • Preliminary Concept Overview
    • Adjustable Legs
    • Locking Casters
    • Rubberized Bottom
    • Two Separate Pieces: Rolling Stand and Board
    • Plexi-Glass Case and Wooden Frame
    • Activities
  • Specifications
    • Board Size: Approximately 20" X 24"
    • Table Adjustability: 2 feet to 3 feet

Final Design Overview

  • Base Box
    • Straps for Stability
    • Rubberized Contact Surfaces for Increased Friction
    • Square Design
      • Increased Versatility
    • Housing for Modular Activity Boxes
    • Primarily for Prone Stander
    • Open Face


  • Gear Jack-In-The-Box/Pulley Treasure Chest Module
    • Gear Jack-In-The-Box
      • Horizontal Cranking Motion Transferred to a Jack-in-a-Box
      • Exercises and Practices Repetitive Circular Motion
      • Suspense Element as Reward
      • Lexan Lid
  • Pulley Treasure Chest
    • Transfers a Pull of a String into Vertical Motion
    • Ratcheting, Cam System
    • Raises Small Box out of Modules Surface
    • Lexan Lid
  • Wire Maze Module
    • Series of Tasks for Greater Reward
    • Threaded Rod with Nut
    • Wire Maze Originating at end of Threaded Rod
    • Key attached to Nut
    • Unlocks Treasure Trove
    • Two Tracks on Module
    • Wooden Lid
  • Light Up Peg Module
    • Pegs of Different Shapes
    • Depress Small SPST Pushbutton Switch Set into the Modules Surface
      • Triggers Four LED Bulbs to Flash Momentarily
    • Possible TTU Configuration
    • Lexan Lid
  • Circuit Diagram for One Peg


Describe the three types of analysis performed on the design. Use equations and schematics as needed.

Engineering Analysis: Peg Lighting System

This activity uses matched pegs and holes, pushbutton switches, and LEDs to stimulate the child visually. The pegs will depress the switches on a momentary basis.

This analysis determines an appropriate number of batteries for each button/peg system. Conclusion Reached: One "AA"


Engineering Analysis: Gear Jack-In-The-Box System

This activity utilizes a set of gears mounted on shafts and either meshed or connected with a belt to turn a gear mounted on the handle of a jack-in-the-box. The gears are turned with a crank mounted above the surface of the box.

This analysis shows the necessary gear size ratio to achieve a desired output/input velocity ratio.


Engineering Analysis: Pulley Treasure Chest System

This activity transfers motion from a pull-cord to a shaft that the cord is wrapped around. The shaft, which is connected to a ratcheting mechanism, rotates and is pulled back by a spring. The ratchet turns a cam, causing a small treasure chest to rise up from the box.

This analysis determines the output/input force ratio for a fixed shaft radius and variable cam length.


Bill of Materials

Item Quantity Price Location
Oak Hardwood Plywood: Item # 6217; Model # 00062 2 29.76 Lowes
Oak Hardwood Plywood: Item # 119983; Model # LBR119983 1 24.97 Lowes
Physics Workshop 1 55.00 Discovery Depot
Jack-in-the-Box 1 25.00 Discovery Depot
Ratchet 1 10.00
LED Bulbs 3 1.97 Lowes
Butt Splice Connectors 1 2.48 Lowes
2-1/2" Zinc Safety Hasp 1 2.98 Lowes
Brass Economy Sash Lock 1 2.17 Lowes
Satin Nickel Door Chain 1 2.98 Lowes
3/16" - 3' Steel Round Stock 3 2.33 Lowes
3/8" - 1' Plated All Thread 1 1.23 Lowes
1/4" - 3' Aluminum Round Stock 2 3.27 Lowes
Gatehouse 3" Brass Plated Barrel Bolt with Screws 1 2.98 Lowes
Master Lock Alpha Combo Lock 1 7.96 Lowes
2 Pack Light-Duty Lashing Straps 1 7.97 Lowes
Clear Lexan Polycarbonate Rod 3 8.28
Skid Guard Safety Tape 1 5.97 Lowes
Galvanized Hex Nuts: Item # 67341; Model # 810509 6 0.21 Lowes
Adjustable Table 1 79.99
1 45.70 euro
7/16" Spring Snap 1 3.79 Lowes
SPST Momentary Pushbutton Switch 1 2.99 Radioshack
8 "AA" Battery Holder 1 1.99 Radioshack
Clear Lexan Polycarbonate Sheet: Part # 8574K57 1 81.68
Clear Lexan Polycarbonate Sheet: Part # 8574K55 1 33.89
100-Pack Flat Head Wood Screws: Item # 68355; Model # 35048 1 3.97 Lowes
Master Lock Steel Body Lock: Item # 60079; Model # 3KAD 1 6.97 Lowes
TOTAL 412.78

Assembly Instructions

  • Cut Pieces of Wood for Main Box and Modules
    • Construct Modules
    • Construct Main Box

Assembling Boxes

Completed Module

*Staining and Varnishing the Wood

Stain in Progress

Watching the Proverbial Paint Dry

*Creating the Modules

Making a Rough Cut around a More Delicate Element

Slowly Refining the Original Rough Cut

Assembling the Jack in the Box Mechanism

Shortly after bending the steel to create custom wire tracks, a fresh coat of "metal" appeared to make them shiny and new.

Putting Together "Treasure" Chests

Getting Much Closer

Implemented Design

Completed Wire Maze Module

  • Task: Develop a challenging task for Jude to learn fine motor skills
  • Key Design Elements
    • Wire Tracks Welded onto All Thread
    • Keys to Chests Attached to Easy-to-Use Nuts
  • Completed Jack in the Box Module
    • Task:
    • Key Design Elements
  • Completed Light Up Peg Module
    • Task:
    • Key Design Elements

Summary and Conclusions