1. Scratch Robots Coin Sensor Click here to see video (not active yet)

2. Scratch Robots www.build-it-yourself.com Coin Sensor – How does it work? 4)Build a platform channel for a quarter. 1) Build a long lever. 2) Attach one end to a hinge. 3)Glue an arm to the lever as near the hinge as possible that rests on the Space Bar key. 5) When a quarter is dropped in the channel, it pushes the arm down which presses the Space Bar key. The quarter then rolls into a can that collects the quarters.

3. Scratch Robots www.build-it-yourself.com Coin Sensor Overview 4”x4” cardboard 3”x3” foamie hinge 8” coffee stirrer sticks Straw Coffee stirrer stick arm positioned to rest on the Space Bar The straws give you flexibility to adjust the coin platform. Don’t glue to coffee stirrer sticks! Find a book or block of wood that is roughly the same thickness as your computer keyboard. Tape the book to the table and tape your arm hindge to the book.

4. Scratch Robots www.build-it-yourself.com Materials: Coffee stirrer sticks from Starbucks Straws from Dunkin Donuts Cardboard Foamies Masking tape Tools: Scissors Hot glue gun Ruler Coin Sensor Materials picture

5. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 1 Show how to break sticks cleanly. 1.Cut 4” square cardboard. 2.Break coffee stirrer sticks and hot glue to cardboard. This will make a rigid platform. 1.Instructions

6. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 2 1.Glue coffee stirrer sticks to a 3”x3” square of flexible foamie. 2.Glue one edge of the hinge to the cardboard platform.

7. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 3 1.Add sections to the lever until it is long enough to span your computer key board. 4”x4” cardboard 3”x3” foamie hinge 8” coffee stirrer sticks

8. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 4 1.When the lever is long enough to span your computer keyboard, create one last section. Glue one end of the final section but NOT the outside end !!! 4”x4” cardboard 3”x3” foamie hinge 8” coffee stirrer sticks Straw

9. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 5 1) Insert the final section into the straw. 4”x4” cardboard 3”x3” foamie hinge 8” coffee stirrer sticks Straw

10. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 6 1.Build a platform to channel a quarter into a tin can. The straws enable you to position the quarter channel so it catches a quarter from your model. 2.Build the quarter channel.

11. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 7 1.Glue or tape the quarter channel to the platform on the straws. 2.Insert the lever ends into the straws on the quarter channel platform.

12. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 8 1.Mount your lever on a book or block of wood. 2.Tape the book or block of wood to the table next to your computer keyboard. 3.Glue an arm to the lever so that it rests on the Space Bar key. Be careful not to get glue on your keyboard !!! Lift the lever away from the keyboard.

13. Scratch Robots www.build-it-yourself.com Coin Sensor – Step 9 1.Add a module that can drop a quarter into the quarter channel. 2.Position a cup or tin can to catch the quarters. 3.Now you can write a Scratch program to play audio clips and control a black or white square on the computer screen. When the square is black, your motor controller will turn a motor off. When the square is white, your motor controller will turn a motor on.