Oxygen

[Hardy Heinlin]

:-)

Anyone out there who uses oxygen masks?

Do we need a network interface for that?

PSX-to-hardware: Software oxygen empty > Pilot gets red head

Hardware-to-PSX: Oxygen in use x minutes > PSX EICAS indications change

The latter is easier to model :-)


0-0

[farrokh747]

HI Hardy -

I have O2 Masks - the box has a hose connector for O2, and a jack for the mask mic.
Opening the O2 box doors activates the O2 flow, and enables the mask mic (Boom mic disabled)

Most of the indications and controls seem to be on the mask itself

I'm assuming there is a switch/latch on the mask door that activates O2 flow and mic - so a variable for the door open/closed state should be enough. Apart from that, and the crew O2 press value, the aircraft computers don't have any other input to know what's going on with the O2 mask -

Pulling out the O2 mask would activate the variable, then software O2 would deplete till low "CREW OXY LOW" msg on EICAS -

If the builder wants to take it further, a solenoid valve would have to be placed before the O2 inlet, which would shut off when O2 level is low/over.

anyone?

Farrokh

[Shiv Mathur]

PSX-to-hardware: Software oxygen empty > Pilot gets red head

Wouldn't the head turn blue, rather ?

(Purely in the interest of sim accuracy !)   :?

[Hardy Heinlin]

Good morning.

OK, I'll add a simple network variable, or two, for the oxygen status.

PSX-to-hardware: Software oxygen empty > Pilot gets red head

Wouldn't the head turn blue, rather ?

(Purely in the interest of sim accuracy !)   :?

Good question. Maybe it also depends on the planet. Mr. Spock gets green, Earthlings get red, and Royals get blue.


(--)

[martin]

Moi,

inhabitants of the Blue Planet get purple.

 :oops:

[Phil Bunch]

Insects' "blood" is different:

"Hemolymph fills all of the interior (the hemocoel) of the animal's body and surrounds all cells. It contains hemocyanin, a copper-based protein which turns blue in color when oxygenated, instead of the iron-based hemoglobin in red blood cells found in vertebrates, thus giving hemolymph a blue-green color rather than the red color of vertebrate blood. When not oxygenated, hemolymph quickly loses its color and appears grey."

- Wikipedia, URL below:

https://secure.wikimedia.org/wikipedia/en/wiki/Hemolymph

I have a distant memory that some bugs' copper-based "blood:" causes their bodily fluids to be green rather than red seen with mammalian blood.  

Haven't checked my own blood recently...what if it has turned green?!

[Will]

Maybe I'm missing the joke, but why would the pilots' get red heads?  Lack of oxygen (hypoxia) leads indeed to cyanosis, which makes people blue (lips, fingers, cheeks, etc.).  One exception is carbon monoxide poisoning, in which CO binds to hemoglobin making carboxyhemoglobin, which reduces the oxygen carrying capacity of the blood but gives people a "cherry red" appearance.  But other than carbon monoxide, hypoxia makes people blue.

Unless, Hardy, you were meaning that the pilots would get red because they were angry that the oxygen tank was empty?

[Hardy Heinlin]

But why is Homer Simpson yellow then?

[Will]

He's a yellow-bellied sapsucker.

[Hardy Heinlin]

Cyanosis, carboxyhemoglobin, sapsucker ...

M-hm, m-hm :-)

...

Aha, you mean a sphyrapicus?

[Hardy Heinlin]

A yellow-bellied sapsucker with white belly and red head!!

[Will]

That must be one hypoxic, Vulcan bird.

[Zinger]

During periodic high altitude chamber training, you face others, climbing without oxygen. The guys opposite me always turned pale purple.

[tl1975]

Zinger: 100 points.

Less O2 in the blood, less darker is your blood. Remember, the blood after lungs is darker in color than before it passes the lungs (returnline).

Less O2 =  lighter blood = paler skin. Voila.

[farrokh747]

Opening the O2 box doors activates the O2 flow, and enables the mask mic

So this appears to be incorrect....  I had a closer look at the box, and there's no sw/lead from the o2 box doors...  

there are 4 pins from the jack at the rear of the box:
2 for mic audio
2 for mic on/off - i cant figure out what exactly activates the mic... i put on the mask and checked for the on/off signal with a meter, nothing.. (V weird sight, mask with meter)

anyone has an idea what triggers this?


fc

[John H Watson]

The schematics are not very helpful

Our oxy box cannon plugs have pins as follows:

A: mic line
B: shield (used as the second mic wire)
C: not used
D: not used
E: mask on/off switch output to Audio Management Unit  
F: earth for switch


The door switch should activate the oxy mask mic.

Rgds
JHW

[John H Watson]

P.S. For clarification, the mic is not switched on/off at the box. It is permanently hotwired to the AMU. However, the switch on the door sends a signal to the AMU to use the oxy mask input (and stop the boom headset mic working)

[John H Watson]

So this appears to be incorrect.... I had a closer look at the box, and there's no sw/lead from the o2 box doors...

Are you sure you have a 747-400 oxy box? Pre-400, there were probably external controls for activating the mic. i.e. a BOOM/MIC switch on the audio control panel

[farrokh747]

yup, from 744.....  i'll take a few pics and send you.... re the connector, apart from the mic leads inside the box, there is another lead going to a small component placed at the bottom, inline with the o2 hose....  that's why i thought it may be triggered by airflow.... you have to pull out the o2 mask completely from the box to see the bottom..

i see the A, B, C PINS at the rear....

will check again...

cheers

[John H Watson]

Our masks have visible wiring (to/from the switch)

Not sure what's going on with yours