Android Bluetooth Controlled MP3 Player

I have created a bluetooth android controlled mp3 player which works great apart from some mild noise. I am using a switch mode power supply for testing which is noisy. Is there a shield or module out there which can be integrated to eliminate line noise. I can build a filter, but would much prefer to buy a shield.

Hi Mark,
There aren’t really any shields designed just to filter out noise, but the first place I’d start would be using a quieter power supply, are you regulating down the voltage or using the switch mode’s voltage? Perhaps a bit more info about your project will help us to help you.

G’Day Sam,

Thanks for your reply. Switch modes are cheap and light and a filter is easy to build. A shield would have been nice but I guess I will have to build it anyway. Yes! I am regulating down the supply for certain parts of the project as many of the components are sensitive to irregularities in voltage. Running on batteries eliminates most of the noise, but the challenge is the switch mode.

Kind regards,


Switch mode power supplies are great, but they do have their challenges. What kind of noise are you getting? Just ripples and typical switching noise? You could use a Zener diode to regulate to a slightly lower voltage, and I would also suggest ensuring that you’ve got some nice 47uF and 100uF directly after the power supply to give a nice stable voltage, and then some 100nF capacitors placed as close as possible to sensitive components.

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Thanks Sam. These are very good suggestions, but switch mode power supplies can produce a variety of noise types which need to be dealt with more seriously. I am impressed with the Core Electronics D class amplifier which I purchased recently and have implemented. I need to give it the respect it deserves. I am Currently watching a video on You tube by KainkaLabs which brilliantly explains the noise problems associated with switch mode power supplies. Kainka offer a good filter to remedy most of the problems. Infact, it incorporates most of your suggestions except for the Zener diode. I will definitely build it just for the fun and experience and welcome any more suggestions. Go to love the projects…

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Hi Mark, glad to hear you found some good resources. Most of those methods are fairly standard for filtering out noise. I’m not sure if it’s mentioned in the video you watched, but another trick for getting a seriously clean power supply is using a series resistor directly after the supply’s power rail. A beefy high wattage resistor of the 1-10Ohm range will allow you to create a more specific RC filter for some of the switch noise you’re getting.

Sounds like a great project by the way, be sure to visit our Projects section and submit your project for some sweet, sweet store credit!