Hey all, I posted this on eevblog but with a bunch of views and only 1 response from someone else, and a crapload of searching to no avail, I figured I would try here.
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Hey all, I have this bluetooth receiver module for a project I'm working on (and am almost done) however I've had a couple issues.
http://www.ebay.ca/itm/Bluetooth-BL...R-/370916284758?ssPageName=ADME:X:AAQ:CA:1123
First one was the microphone not working, however I think it's just not enabled for this version, disappointing, but not a major issue.
The main issue is noise on the speakers, it sounds like general radio interference, a bit of buzzing, some beeping, kind of static-y (can't find any cables I could use to record it right now)
Anyways, this noise changes when I touch the antenna, with my finger or an alligator clip wire this reduces the noise level drastically, though it's still audible with no audio playing.
I'm wondering if you guys know of any way I could reduce this. My first thought was an external bluetooth antenna, but I don't have time to wait for it to get here, what seems odd is that adding in just a random bit of wire helps, when bluetooth needs a pretty specific shape of antenna pattern.
I also am going to try coupling capacitors on the speakers, and perhaps on the power supply (the noise was actually louder when connected to a Lithium ion battery than when it was connected to my power supply) though considering touching the antenna is changing this, I'm not sure if these would work or not. I've tried some 22uf electrolytic on the speakers (only the negative side, but the diagram on the wiki shows some on both) to no avail, and unfortunately everything will be closed for quite a while yet so I'll have to see what I can salvage.
I think I saw mention of 200 or 300uf capacitors being an appropriate value for this sort of use? Seems a tad high, but I haven't done any audio stuff before this.
www.elecfreaks.com/wiki/index.php?title=BLK-MD-SPK-B
edit: also got it to be fairly quiet just now but there's a slight rhythmic clicking, about twice per second.
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I've tried 22uf capacitors on the speakers, a 1:1 isolation transformer on the speakers (with and without caps), 22 and 47uf capacitors on the power input, and a 47uf capacitor connected to 1v8, all without any change.
I've noticed that touching, or connecting a wire to the antenna makes the sound much quieter, though you can still hear it and occasionally it still gets very loud.
This is exactly the sort of stuff I'm hearing, except that I don't have any other circuitry attached, the only posts I can find about noise ended up being a ground loop problem relating to an external amplifier. As you can see, I have the board by itself, mounted to a perfboard so that I could break out the connections more easily.
"
Hey all, I have this bluetooth receiver module for a project I'm working on (and am almost done) however I've had a couple issues.
http://www.ebay.ca/itm/Bluetooth-BL...R-/370916284758?ssPageName=ADME:X:AAQ:CA:1123
First one was the microphone not working, however I think it's just not enabled for this version, disappointing, but not a major issue.
The main issue is noise on the speakers, it sounds like general radio interference, a bit of buzzing, some beeping, kind of static-y (can't find any cables I could use to record it right now)
Anyways, this noise changes when I touch the antenna, with my finger or an alligator clip wire this reduces the noise level drastically, though it's still audible with no audio playing.
I'm wondering if you guys know of any way I could reduce this. My first thought was an external bluetooth antenna, but I don't have time to wait for it to get here, what seems odd is that adding in just a random bit of wire helps, when bluetooth needs a pretty specific shape of antenna pattern.
I also am going to try coupling capacitors on the speakers, and perhaps on the power supply (the noise was actually louder when connected to a Lithium ion battery than when it was connected to my power supply) though considering touching the antenna is changing this, I'm not sure if these would work or not. I've tried some 22uf electrolytic on the speakers (only the negative side, but the diagram on the wiki shows some on both) to no avail, and unfortunately everything will be closed for quite a while yet so I'll have to see what I can salvage.
I think I saw mention of 200 or 300uf capacitors being an appropriate value for this sort of use? Seems a tad high, but I haven't done any audio stuff before this.
www.elecfreaks.com/wiki/index.php?title=BLK-MD-SPK-B
edit: also got it to be fairly quiet just now but there's a slight rhythmic clicking, about twice per second.
"
I've tried 22uf capacitors on the speakers, a 1:1 isolation transformer on the speakers (with and without caps), 22 and 47uf capacitors on the power input, and a 47uf capacitor connected to 1v8, all without any change.
I've noticed that touching, or connecting a wire to the antenna makes the sound much quieter, though you can still hear it and occasionally it still gets very loud.
This is exactly the sort of stuff I'm hearing, except that I don't have any other circuitry attached, the only posts I can find about noise ended up being a ground loop problem relating to an external amplifier. As you can see, I have the board by itself, mounted to a perfboard so that I could break out the connections more easily.
