This project is a great example of sending notifications such as SMS and email with an Arduino. By using a service such as Amazon's SNS notification service, the complex work of delivering notifications is done for you automatically. Furthermore you get complete control over how and where notifications are delivered through Amazon's web interface.

Some interesting ways you might extend this project include:

• Create a do-it-yourself 'security system' to send you notifications when doors or windows are unexpectedly opened at home. Be alerted when a nosey sibling is going in your room!
• Use a load cell/scale to sense how much food is in the dish and send more accurate status messages.
• Create different SNS subscriptions such as HTTP endpoints (good for notifying other web services you build) or SQS queues (good for notifying other Amazon web services).
  
• Use the signature generation code in the sketch to call other Amazon web services, such as the S3 storage service.

What ways can you think of to extend this project?

Have fun adding notifications to your own Arduino projects!