Code Your Customers on Scratch

Open scratch.mit.edu and click Create to start a new project.

Click the Stage and choose or paint a shop backdrop with a counter and a door.

Add a shopkeeper sprite and place it behind the counter.

Add at least two customer sprites and give each a different costume then place them offstage near the door.

For each customer sprite create a variable named budget for this sprite only and add a block when green flag clicked set budget to pick random 5 to 20.

Create at least two item sprites for sale and for each item create a variable named price for this sprite only and set price to a number when green flag clicked.

Create a global variable named currentPrice and program each item so that when the item is clicked it sets currentPrice to its price and broadcasts itemSelected.

For each customer sprite add blocks so that when the green flag is clicked the customer waits pick random 1 to 4 seconds then shows and glides 1 second to the counter.

For each customer sprite add a when I receive itemSelected block that checks if the customer is touching the counter and if so broadcasts askPrice.

In the shopkeeper sprite add a when I receive askPrice block and make the shopkeeper say join "Price is $" currentPrice for 2 seconds.

In the customer sprite add a when I receive askPrice block that waits 1 second then if budget >= currentPrice changes budget by -currentPrice broadcasts buy and says "Thanks" else says "I can't afford it" and glides 1 second out the door.

In the shopkeeper sprite add a when I receive buy block that changes a shopMoney variable by currentPrice plays a sound and makes the bought item hide or show a sold look.

Click the green flag to test the project and then tweak budgets prices and timings until customers enter ask and buy as you want.

Share your finished interactive shop project on DIY.org.