I'm playing around with a networked sensor alarm. I've got the sensors (smoke, gas, temperature and humidity).
I want this to replace our smoke alarms by lighting up (LEDs), sending messages (Twitter, EMail, SMS, ...) and making lots of noise.
I know how to light things up and send messages.
But I need to make a lot more noise than I know how to at the moment. I have a KPEG110 piezo buzzer and a COM-11089 PCB mount speaker and I can make tones on these. But this is nowhere near the sort of volume I need for an alarm.
What can I use that I can easily hook up to my Arduino and will fit in a nice tiny form factor?
Thank you in advance for any advice and suggestions.
Yeah, it's probably easier to buy a loud buzzer with built-in drive cktry than build one.
G_M's buzzer is a monster, 90mA and 110 dB!
OTOH, if you're building one yourself, the secret is use a largish drive voltage, and
pulse it at the resonant frequency specified for the device. I have a CEM-1203, 42-ohm
magnetic [not piezo] transducer that I tested recently.
I drove it with a 2N3904 NPN inverter and tried 3.3V, 5V, and 9V. Its resonant frequency
is about 2 Khz, and when driven well off that frequency, the loudness was way down.
Also, at 3.3V the sound was weak, at 5V the volume it was good, but at 9V and 2 Khz,
it was so loud and obnoxious, it drove me out of the room.
So, you just need to choose the design parameters properly. Also, in this case, the currents
were somewhat higher than the Arduino I/O pins can output, so the volume will never be
very high without using the inverter driver ckt. It's all a matter of the right ckt.