Piezo elements come in handy when you need to detect vibration or a knock. You can use these for tap or knock sensors pretty easily by reading the voltage on the output. They can also be used for a very small audio transducer such as a buzzer.
This is not a true piezoelectric speaker but behaves similarly. Instead of a piezoelectric crystal that vibrates with an electric current, this tiny speaker uses an electromagnet to drive a thin metal sheet. That means you need to use some form of alternating current to get sound. The good news is that this speaker is tuned to respond best with a square...
The buzzer has a 3-pin header which connects directly to the RedBot Mainboard or via male to female jumper wires. Use the included RedBot library to detect sound alarms and make some noise.
This through-hole speaker is great for projects where you need something that sounds better than a piezo buzzer but don’t have room for a full-blown speaker. This 30mm diameter speaker is encased in plastic and will handle about 100mW of power.
If you want to get some sound out of your project but have a tight space budget, this is a good way to do it. This 0.25W, 8Ohm speaker is only 40mm in diameter and just over 4mm thick, the same kind you might find in one of those “talking greeting cards”.