Compass Questions ?

Dave Doe wrote:
In article ,
, Dave Doe says...

In article , lid, Bob
says...

Hi,

Thanks for replies and help.

What I was referring to are the new, modern, "glass" displays where most
everything shown is derived
from transducers located elsewhere.

e.g. when a display shows a Heading of, e.g., 075, it is of course
getting this info. from some kind of transducer, located elsewhere.

Is it derived directly from GPS ?
A Hall effect compass ?
or,... ?

Thanks again; interesting subject.

Well I'm not sure on that - perhaps others will reply. However,
cellphones usually use one or more magnetometers (hope I spelt that
right ). A GPS can't get a magnetic heading, only True.

I play with Arduino's a bit - and Googling 'arduino magentometer' gives
a few results, eg...
http://bildr.org/2011/01/hmc6352/
http://bildr.org/2012/02/hmc5883l_arduino/
http://eclecti.cc/hardware/hmc5843-m...ry-for-arduino

I *assume* that the compass in a glass display uses the same sort of
technology.

Apologies to the apostrophe police - that's terrible!

--
Duncan.

The display in a glass panel is GPS course. You need a magnetic compass to know
your heading. The difference between the two is wind correction, magnetic
variation and compass deviation.

While I don't doubt that someone could create a device that would send
magnetic heading info to a glass panel, it would have to be some obvious
secondary display. You want to be looking at your true course if you want
to get from A to B.

--
Don Poitras

In article , , Don
Poitras says...

Dave Doe wrote:
In article ,
, Dave Doe says...

In article , lid, Bob
says...

Hi,

Thanks for replies and help.

What I was referring to are the new, modern, "glass" displays where most
everything shown is derived
from transducers located elsewhere.

e.g. when a display shows a Heading of, e.g., 075, it is of course
getting this info. from some kind of transducer, located elsewhere.

Is it derived directly from GPS ?
A Hall effect compass ?
or,... ?

Thanks again; interesting subject.

Well I'm not sure on that - perhaps others will reply. However,
cellphones usually use one or more magnetometers (hope I spelt that
right ). A GPS can't get a magnetic heading, only True.

I play with Arduino's a bit - and Googling 'arduino magentometer' gives
a few results, eg...
http://bildr.org/2011/01/hmc6352/
http://bildr.org/2012/02/hmc5883l_arduino/
http://eclecti.cc/hardware/hmc5843-m...ry-for-arduino

I *assume* that the compass in a glass display uses the same sort of
technology.

Apologies to the apostrophe police - that's terrible!

--
Duncan.

The display in a glass panel is GPS course. You need a magnetic compass to know
your heading. The difference between the two is wind correction, magnetic
variation and compass deviation.

While I don't doubt that someone could create a device that would send
magnetic heading info to a glass panel, it would have to be some obvious
secondary display. You want to be looking at your true course if you want
to get from A to B.

The OP is asking about just about such a device. And it's clear they do
exist in a glass display (a compass that is).

Take for example, the Cessna website. If you navigate to say the Cessna
TTx - and check out the glass Avionics section, and look at Equipment
Details (rather than Standard Features), it specifies a Magnetometer ...
"GMU-44 Magnetometer (dual)"

Albiet a compass is almost obsolete and uncessary with todays navigation
equipment, but let's not forget runways - still lined up and named
magnetic. Makes me wonder when that will change.

--
Duncan.

Dave Doe wrote:
In article , , Don
Poitras says...

Dave Doe wrote:
In article ,
, Dave Doe says...

In article , lid, Bob
says...

Hi,

Thanks for replies and help.

What I was referring to are the new, modern, "glass" displays where most
everything shown is derived
from transducers located elsewhere.

e.g. when a display shows a Heading of, e.g., 075, it is of course
getting this info. from some kind of transducer, located elsewhere.

Is it derived directly from GPS ?
A Hall effect compass ?
or,... ?

Thanks again; interesting subject.

Well I'm not sure on that - perhaps others will reply. However,
cellphones usually use one or more magnetometers (hope I spelt that
right ). A GPS can't get a magnetic heading, only True.

I play with Arduino's a bit - and Googling 'arduino magentometer' gives
a few results, eg...
http://bildr.org/2011/01/hmc6352/
http://bildr.org/2012/02/hmc5883l_arduino/
http://eclecti.cc/hardware/hmc5843-m...ry-for-arduino

I *assume* that the compass in a glass display uses the same sort of
technology.

Apologies to the apostrophe police - that's terrible!

--
Duncan.

The display in a glass panel is GPS course. You need a magnetic compass to know
your heading. The difference between the two is wind correction, magnetic
variation and compass deviation.

While I don't doubt that someone could create a device that would send
magnetic heading info to a glass panel, it would have to be some obvious
secondary display. You want to be looking at your true course if you want
to get from A to B.

The OP is asking about just about such a device. And it's clear they do
exist in a glass display (a compass that is).

Take for example, the Cessna website. If you navigate to say the Cessna
TTx - and check out the glass Avionics section, and look at Equipment
Details (rather than Standard Features), it specifies a Magnetometer ...
"GMU-44 Magnetometer (dual)"

Albiet a compass is almost obsolete and uncessary with todays navigation
equipment, but let's not forget runways - still lined up and named
magnetic. Makes me wonder when that will change.

--
Duncan.

You're right. I was wrong. It makes sense that the glass HSI would need
to work like the mechanical one and that gets set manually to the
current compass setting.

--
Don Poitras