Now you have a working system, you can consider adding more functionality to it. We provide you with some ideas in the following sections with links that will help you to implement the functionality.
While an LED is a neat feature, it would be nice to know which item has only one left in the inventory. The LED also does not distinguish between multiple items being in short supply. In fact, we have to check via the web browser to see what items are stocked.
One way around this is to integrate a screen with the Raspberry Pi. You could place the Raspberry Pi in your kitchen and check the screen to see what is in short supply.
Thankfully this is an easy task. The Raspberry Pi Foundation released a digital touch screen you can connect to your Raspberry Pi's GPIO pins.
You can read more about it here: https://www.raspberrypi.org/products/raspberry-pi-touch-display/.
In addition, hooking up a screen like this will allow you to experiment with the skills you learned in Chapter 6, Low-Level Graphics Programming.
A useful feature could be to receive an e-mail when somebody uses the last of an item. For example, you could be at work and somebody uses the last egg in the fridge. This would then trigger an e-mail reminding you to pick up some more on the way home.
Implementing e-mails via Python is very simple. The following guide on the Python website shows how you can expand a program to support this functionality: https://docs.python.org/2/library/email-examples.html.
You could, for example, update the edit_item() function to include the e-mail triggering functionality.
If you choose to add e-mail support, an existing e-mail account on a service such as Gmail can be used.
The following website provides an example of how to configure this: http://www.pythonforbeginners.com/google/sending-emails-using-google.
We already looked at the sound capabilities of the Raspberry Pi. Perhaps we could implement some functionality so when we run out of an item a sound plays?
There are a number of ways of doing this, including via Python. As you will remember from Chapter 8, Exploring Sound with the Raspberry Pi 2, we can play sounds via the os.system command, such as:
os.system('mpg123 -q drum2.mp3 &')Expanding your code base to include this would be very simple and could trigger an MP3 when the LED is switched on.