Over the past few months I got many emails asking me for the source code.
You can buy the source code now.
The video and the code above will show you how to build the prototype. But if you want the source file, click here to buy it for $0.99. I spend a few hours exploring it and building it. It might save you an hour or so.
You will get a zip file. Go to your appinventor instance and upload the zip file to create a new project.