automotive electrical noise detector

P

PDRUNEN

Guest
Hi Group,

I am working on a project which will detect if a automobile is running. The
output of sensor would be a TTL high for running and a TTL low for not running.
The circuit will be inside the car, most likely in the glove compartment or
storage compartment. It will not be connected to the automobile and run off of
batteries.

My thoughts are to use a common 455KHz IF filter and amplitude detect or a 10.7
MHz IF filter and do the same.

Which frequency would be better and/or easier to design around? (455KHz or
10.7MHz). How about VHF or a super-reg with a wide bandwidth?

How much gain would a stage following an IF filter require such that it could
be used as a level detect?

Other suggestions? (I want to stay away from any connections into the car).

Paul
 
PDRUNEN wrote:

I am working on a project which will detect if a automobile is running.
Click to expand...
Turn the music off and listen? Change from a Rolls to a banger? Hang a
small bell in the engine compartment? Look at the oil pressure light?

Paul Burke
 
Paul Burke wrote:
PDRUNEN wrote:

I am working on a project which will detect if a automobile is running.

Turn the music off and listen? Change from a Rolls to a banger? Hang a
small bell in the engine compartment? Look at the oil pressure light?

Paul Burke
Click to expand...
How about a solid state air flow detector (vane) in the tail pipe, or
is that too complex?
 
mike wrote:
PDRUNEN wrote:

Hi Group,

I am working on a project which will detect if a automobile is
running. The
output of sensor would be a TTL high for running and a TTL low for not
running.
The circuit will be inside the car, most likely in the glove
compartment or
storage compartment. It will not be connected to the automobile and
run off of
batteries.

My thoughts are to use a common 455KHz IF filter and amplitude detect
or a 10.7
MHz IF filter and do the same.
Which frequency would be better and/or easier to design around?
(455KHz or
10.7MHz). How about VHF or a super-reg with a wide bandwidth?

How much gain would a stage following an IF filter require such that
it could
be used as a level detect?
Other suggestions? (I want to stay away from any connections into the
car).

Paul




ONce had a boat tachometer that had a tunned diode receiver that ran on
ignition noise.
Click to expand...
Make that TUNNEL DIODE

mike
Click to expand...


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PDRUNEN wrote:
Hi Group,

I am working on a project which will detect if a automobile is running. The
output of sensor would be a TTL high for running and a TTL low for not running.
The circuit will be inside the car, most likely in the glove compartment or
storage compartment. It will not be connected to the automobile and run off of
batteries.

My thoughts are to use a common 455KHz IF filter and amplitude detect or a 10.7
MHz IF filter and do the same.

Which frequency would be better and/or easier to design around? (455KHz or
10.7MHz). How about VHF or a super-reg with a wide bandwidth?

How much gain would a stage following an IF filter require such that it could
be used as a level detect?

Other suggestions? (I want to stay away from any connections into the car).

Paul
Click to expand...
ONce had a boat tachometer that had a tunned diode receiver that ran on
ignition noise.
mike

--
Return address is VALID.
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
http://nm7u.tripod.com/homepage/te.html
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
http://www.geocities.com/SiliconValley/Monitor/4710/
 
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