Hello ACC Forum,
Started working with a PIR sensor to turn on a circuit.
Then the PIR circuit was connected to an Arduino microprocessor,
first to operate an LED and then to play a track on
the SparkFun MP3 shield thru headphones.
https://www.sparkfun.com/products/10628
Yesterday I incorporated a couple of SparkFun mono amplifiers
https://www.sparkfun.com/products/11044
This works well and fires atrack on the MP3 shield
when one walks by the motion detector.
But the amplifiers are 1.4 watt and not very loud. The
mono amp Quick Start Guide
https://www.sparkfun.com/tutorials/392
has a hack for increasing the amplifier amplitude
(loudness) by decreasing the gain resistors but
a volume pot is a preferred solution because it is
more flexible.
Unfortunately I purchased a Velleman amplifier
K4003 before I saw the SparkFun Audio Amplifer Kit
STA540.
http://www.vellemanusa.com/products/view/?id=350530
The instructions on the K4003 show three ways of connecting
the amplifier to power: A ring-core transformer,
two twelve volt batteries, and a center tap transformer.
I have the center tap transformer.
The question is about grounding the signal from
the SparkFun MP3 shield.
The Velleman instructions show a ground wire coming
in from the audio source, in this case the MP3 shield
and the Arduino Uno, to a 22K pot and out to a ground pin on the
K4003 amplifier.
But the K4003 amplifier is grounded to the transformer
so it seems like the amplifier system has two different
grounds: one at the transformer and one at the
Arduno/MP3 shield. (But the Arduno/MP3 shield is powered by
the SparkFun Product number TOL-00298
Wall Adapter Power Supply - 9VDC 650mA. So is
the Arduno/MP3 shield grounded to the house mains
just as the transformer is grounded to the house mains?)
Or should I set up a little voltage regulator circuit like
between one side of the center tap transformer to create
a power supply for the Arduino/MP3 Shield so the amplifier and the Arduno/MP3 shield
are both grounded to the transformer?
Is there a better solution?
Thanks.
Allen Pitts, Dallas Texas
Started working with a PIR sensor to turn on a circuit.
Then the PIR circuit was connected to an Arduino microprocessor,
first to operate an LED and then to play a track on
the SparkFun MP3 shield thru headphones.
https://www.sparkfun.com/products/10628
Yesterday I incorporated a couple of SparkFun mono amplifiers
https://www.sparkfun.com/products/11044
This works well and fires atrack on the MP3 shield
when one walks by the motion detector.
But the amplifiers are 1.4 watt and not very loud. The
mono amp Quick Start Guide
https://www.sparkfun.com/tutorials/392
has a hack for increasing the amplifier amplitude
(loudness) by decreasing the gain resistors but
a volume pot is a preferred solution because it is
more flexible.
Unfortunately I purchased a Velleman amplifier
K4003 before I saw the SparkFun Audio Amplifer Kit
STA540.
http://www.vellemanusa.com/products/view/?id=350530
The instructions on the K4003 show three ways of connecting
the amplifier to power: A ring-core transformer,
two twelve volt batteries, and a center tap transformer.
I have the center tap transformer.
The question is about grounding the signal from
the SparkFun MP3 shield.
The Velleman instructions show a ground wire coming
in from the audio source, in this case the MP3 shield
and the Arduino Uno, to a 22K pot and out to a ground pin on the
K4003 amplifier.
But the K4003 amplifier is grounded to the transformer
so it seems like the amplifier system has two different
grounds: one at the transformer and one at the
Arduno/MP3 shield. (But the Arduno/MP3 shield is powered by
the SparkFun Product number TOL-00298
Wall Adapter Power Supply - 9VDC 650mA. So is
the Arduno/MP3 shield grounded to the house mains
just as the transformer is grounded to the house mains?)
Or should I set up a little voltage regulator circuit like
between one side of the center tap transformer to create
a power supply for the Arduino/MP3 Shield so the amplifier and the Arduno/MP3 shield
are both grounded to the transformer?
Is there a better solution?
Thanks.
Allen Pitts, Dallas Texas