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All hail the mighty ZOM
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Discussion Starter · #1 ·
Thinking back to my days of wearing non-disposable contact lenses, I used to get a noticeable mistiness after diving which I reckon was "bent" lenses- microbubbles forming in the plastic.

Now that got me thinking.

How about making a display with 12 windows in them. All with different porous plastics. As you ascend, the bubbles are formed in them and turn milky. You then sit there decompressing until they turn clear enough to read the "ok" behind them.

Hey presto! A visual mechanical deco calculator with not a battery in sight. A bit of a fattie? Then choose a set of 12 plastics that get bent easier.
 

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Thinking back to my days of wearing non-disposable contact lenses, I used to get a noticeable mistiness after diving which I reckon was "bent" lenses- microbubbles forming in the plastic.

Now that got me thinking.

How about making a display with 12 windows in them. All with different porous plastics. As you ascend, the bubbles are formed in them and turn milky. You then sit there decompressing until they turn clear enough to read the "ok" behind them.

Hey presto! A visual mechanical deco calculator with not a battery in sight. A bit of a fattie? Then choose a set of 12 plastics that get bent easier.
I've got a better idea - why not stick a canary into a sealed enclosure and take that down with you? Then if it dies on the way up, you know you've violated your decompression penalty and need to stay down a bit longer. The trick is, of course, to watch the canary on the way up - if he looks happy then go up. If he looks a bit perky and is right off his trill, stay at your current depth until he cheers up. See - foolproof!!!!! Gives a whole new meaning to 'Deco on the Fly', if you ask me...

Of course in order for this to work, you'll need to plumb a gas line into the canary's enclosure so he's breathing the same mix at the same pressure as you are. The added advantage of this is that if the worse comes to the worse, you can use the canary as a 'sanity breath' and suck the gas out of his box. Poor little f*cker won't thank you for it but when push comes to shove, it's good to know that there's a bird there that will give you a quick suck... :D

BTW - don't use budgies as they're real air hogs! Canaries have much lower SAC rates and therefore won't effect your gas calcs...
 

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Please delete all my posts
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I've got a better idea - why not stick a canary into a sealed enclosure and take that down with you? Then if it dies on the way up, you know you've violated your decompression penalty and need to stay down a bit longer. The trick is, of course, to watch the canary on the way up - if he looks happy then go up. If he looks a bit perky and is right off his trill, stay at your current depth until he cheers up. See - foolproof!!!!! Gives a whole new meaning to 'Deco on the Fly', if you ask me...

Of course in order for this to work, you'll need to plumb a gas line into the canary's enclosure so he's breathing the same mix at the same pressure as you are. The added advantage of this is that if the worse comes to the worse, you can use the canary as a 'sanity breath' and suck the gas out of his box. Poor little f*cker won't thank you for it but when push comes to shove, it's good to know that there's a bird there that will give you a quick suck... :D

BTW - don't use budgies as they're real air hogs! Canaries have much lower SAC rates and therefore won't effect your gas calcs...

I think the aliens finally abducted finless and put his mind in bardos body :)
 

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Just not enough dive time.
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9,135 Posts
No you want something with a simialr physiology as a human body, use a goat, I think that idea may have been tried in the past though.

Matt

ps Woz, seriously, sounds like you could be on to something, just need to worry about re-useability and consistent results from the device in the case of say the stuff geting a memory or degrading etc.
 

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Dunno really........ thinking about it
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1,585 Posts
Thinking back to my days of wearing non-disposable contact lenses, I used to get a noticeable mistiness after diving which I reckon was "bent" lenses- microbubbles forming in the plastic.

Now that got me thinking.

How about making a display with 12 windows in them. All with different porous plastics. As you ascend, the bubbles are formed in them and turn milky. You then sit there decompressing until they turn clear enough to read the "ok" behind them.

Hey presto! A visual mechanical deco calculator with not a battery in sight. A bit of a fattie? Then choose a set of 12 plastics that get bent easier.
SoS (IIRC) had a mechanical deco meter in the late '70s.
No too sure how it worked other than not very well.
Semi Permeable membranes ring a distant bell along with lots of levers and cogs.
 

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An Old "New Member"
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115 Posts
"Dive computers, for all their present day sophistication, have very humble beginnings. Long before the days of microprocessors and long-life lithium batteries,
engineers built mechanical devices to simulate (rather than actually calculate) the process of nitrogen absorption in the body’s tissues.

The most successful example of these mechanical devices is the SOS Decompression Meter. More affectionately known as the “Bends-O-Matic,” it was sold in the U.S. by Scubapro and manufactured by the Italian firm, SOS Diving Equipment, Limited. This pneumatic device used a ceramic resistor set between two air chambers (one flexible, one constant) to simulate nitrogen absorption and off-gassing in the body. An indicator needle showed the depth to which a diver could safely ascend. "

From here
When I did my training My D.O. used one of these all the time.
 

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14-9-09
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3,169 Posts
"Dive computers, for all their present day sophistication, have very humble beginnings. Long before the days of microprocessors and long-life lithium batteries,
engineers built mechanical devices to simulate (rather than actually calculate) the process of nitrogen absorption in the body’s tissues.

The most successful example of these mechanical devices is the SOS Decompression Meter. More affectionately known as the “Bends-O-Matic,” it was sold in the U.S. by Scubapro and manufactured by the Italian firm, SOS Diving Equipment, Limited. This pneumatic device used a ceramic resistor set between two air chambers (one flexible, one constant) to simulate nitrogen absorption and off-gassing in the body. An indicator needle showed the depth to which a diver could safely ascend. "

From here
When I did my training My D.O. used one of these all the time.
Yeah, thats the one, looked like a not-so-small 'gas meter' strapped to your arm. I'm still alive so obviously never used one.

BTW, does anyone know if the aforementioned goat has a sister?:redface:
 

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A VS Cash Cow
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17,832 Posts
oddly enough i thought about this on the way home. Didn't there used to be some sort of picture viewer that we used to use as kids. Can't for the life of me remember what it was called but i remember having one.
 

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As well as the SOS meter (dial-a-bend) I remember reading in diver magazine (this must be over 20 years ago as diver was still worth reading) about a groundbreaking invention for controlling your ascent rate. It consisted of some small plastic balls which you released into the water at the start of the ascent. They were engineered to ascend at a safe rate and you simply followed them up and caught them in a little net at the surface. I really can't understand why they didn't catch on...:confused:
 

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Membership Cancelled
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Hey presto! A visual mechanical deco calculator with not a battery in sight. A bit of a fattie? Then choose a set of 12 plastics that get bent easier.
Woz - you obviously are not spending enough time tinkering with your D5. It is a good idea though and a cheaper alternative would be a slice of bacon* - a bit like the divers' equivalent of sea weed for weather forecasting.

* you could choose the cut - e.g. streaky, smoked etc. according to your body type and lifestyle.

I dated a horse for a while.
 

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All hail the mighty ZOM
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26,851 Posts
Discussion Starter · #20 ·
Woz - you obviously are not spending enough time tinkering with your D5.
I am not. I took it all the way to Scapa and didn't use it. However I did have a play on Dobbo's scooters instead off Lyness Pier.

Wheeeeeeeee!
 
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