Propeller Sound Play
![william chan](https://forums.parallax.com/uploads/userpics/RBTCEMRWP85K/nQFR9OII9OM33.jpg)
I connected one of the Propeller IO pin directly (coupled through a 10uF capacitor) to a pcb mounted speaker
my.farnell.com/jsp/search/productdetail.jsp?SKU=1193537
from Star Micronics. I tried to play some simple music.
The specs say 1.5v and 8.3mA only.
I figured there should be enough drive since the Propeller can do 3.2v at 40mA for any IO pin.
But the result was not up to expectations. The sound is much softer than a similar sized 5v buzzer.
How to solve this problem without adding a complex and costly audio amplifier?
Thanks.
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www.fd.com.my
www.mercedes.com.my
my.farnell.com/jsp/search/productdetail.jsp?SKU=1193537
from Star Micronics. I tried to play some simple music.
The specs say 1.5v and 8.3mA only.
I figured there should be enough drive since the Propeller can do 3.2v at 40mA for any IO pin.
But the result was not up to expectations. The sound is much softer than a similar sized 5v buzzer.
How to solve this problem without adding a complex and costly audio amplifier?
Thanks.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
Comments
Leon
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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
How should the transistor be wired?
Class A? How many ohms collector resistor value should I use?
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www.fd.com.my
www.mercedes.com.my
This speaker is rated at only 1.5V and the Propeller's output range is about 3.3V. The output capacitor will tend to limit the current, but the transducer is not designed for this use.
Post Edited (Mike Green) : 9/25/2008 1:45:55 PM GMT
Compared to mobile phone speakers, these are large!
How does mobile phones get so loud?
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www.fd.com.my
www.mercedes.com.my
Post Edited (william chan) : 9/27/2008 8:24:18 AM GMT
I would say, if you output a squarewave with that frequency, you get a loud beeep.
For Music, you need a little electromagnetic speaker.
Andy
It must be a coil speaker.
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www.fd.com.my
www.mercedes.com.my
I've discovered that speakers like this require a resonant cavity for maximum sound performance. Try applying some shrink tubing to it, as illustrated in the catalog page for the Parallax SoundPAL. You may need to experiment with the length for best results. Also, see if a 100uF cap improves the sound output.
-Phil