Douglas Fir wrote:
Paul,
The design looks simple enough. Do you have the schematic for intergrating
a series of LEDs based on signal input strength? This is an easy project
for us to tackle inexpensively over here. Honestly the biggest expense would
be the PC board printing. Putting this units together can be done by my
staff here if anyone wants one real cheap. What would be the ideal package
design for the unit. Round? Panel mount? Neat I hope.
I can't read the IC number.
Douglas
LM386N single chip audio amp. National semi six pin minidip.
The bar graph LED would be a nice additional touch.
No schematic but I think there are bar graph chips.
Hang on I'll check google............................
Here you are ..... first one that popped up.
The sound is better as the brain is an excellent real time signal processor.
My vote would be a small rectangular panel mount with a mini head phone
jack. Sign me up for one sight unseen.
Paul Lamar
http://www.national.com/search/search.cgi/design?keywords=LM386
______________________________________________________________________________________
The LM386 is a power amplifier designed for use in low voltage consumer applications.
The gain is internally set to 20 to keep external part count low, but the addition of
an external resistor and capacitor between pins 1 and 8 will increase the gain to
any value from 20 to 200.
The inputs are ground referenced while the output automatically biases to one-half
the supply voltage. The quiescent power drain is only 24 milliwatts when operating
from a 6 volt supply, making the LM386 ideal for battery operation.
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Paul,
Will this work with the stock Mazda knock sensors? I'd rather use them, they are a dime a dozen from junkyards, they get pulled and thrown in a bin. They also fit the engine nicely. If so, sign me up. (my 20B came with three, all the 93+tt's come with two.)
Marc Wiese
Yes they will. To clarify my sentence about signal processing. The human brain
can distinguish between normal engine noise and ping or knock. I think we have
all heard this sound in our cars at one time or another.
The problem with an airplane is too much prop noise. The ping is
not heard so we need a amplifier to feed the knock signal into a head set.
We can then hear it when it happens. Generally, as you well know, if you are
running three piece seals that is too late. The seal may already be shattered.
So all you turbo guys out there go to the latest two piece 2 mm seals or the
two piece 3 mm seals if you are building a turbo engine and monitor the knock.
Paul Lamar
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