Homemade PO2 meter

Corallaro · 28th March 2007, 21:56

Hi Marek ...see this link

PO2PCB

if you send an email to Dan ..

it send you complete electric scheme

Giovanni

marekm · 29th March 2007, 03:59

Hi guys,

Thanks for the links, but I have studied those pages months ago and found they both rely on integrated circuits. However, I'm looking for a fully analog way of measuring the millivolts coming out of the O2 cells.

Cheeers.
-Marek

PeteS · 29th March 2007, 07:49

Quote: (Originally Posted by marekm)

Thanks for the links, but I have studied those pages months ago and found they both rely on integrated circuits. However, I'm looking for a fully analog way of measuring the millivolts coming out of the O2 cells.

I assume that by "analogue" you mean "discrete components"? After all, not all IC's are digital, and I've worked on digital systems made up from discrete components!

In my experience, IC's will make the design work simpler, and the unit more reliable.

So why use discrete components? Why not IC based Op-Amps? Or even a MicroPIC with A-D inputs and multiple 16 bit outputs to drive the LED's?

I don't think there is anything wrong in your approach, you just seem to be doing it the hard way.

The use of an acrylic tube for the display is nicely executed though. I built a similar one some years ago with a vibration sensing switch that fired up the electronics when the tube was tapped, and then shut down 20 seconds later.

Corallaro · 29th March 2007, 10:45

HI

about an analog solution...i make some search and some calculation but i don't find any microamperometer / microvoltmeter to use

the analog solution form me is is "cell-resistor-analog microamperometer" no battery!

someone can help us??

someone have the scheme/components of analog display of Prism Topaz or MK15??

or any info about the microamp?:

JEWELL ELEC.
INSTR., INC
MODEL HS1
821886-215

marekm · 29th March 2007, 14:34

Hi PeteS,

Fristly, thankyou for correcting my spelling of analogue

. The point of building my own PO2 meter from scratch is to avoid the black box scenario I've currently got with off the shelf DPM's. Throwing in IC brings me back to the black box scenario I am in now. Also, this is just and idea, and time will tell if it is a bad one.

In the mean time, I would also like to build a batteryless PO2 meter, but don't know how the PRISM one works, so I don't know how to go about it yet.

Cheers.
-Marek

***caveseeker7*** · 29th March 2007, 14:48

The analog gauges of the MK and PRISM run directly off the sensors.
Don't know the inside of the gauges though, never cracked one open.
They're supposed to do that themselves I believe.

Seriously though, the drawback of needle gauges are that they are
prone to shock/impact damage. You might want to look into some
digital option, many MK and PRISM divers are.

If however you're set on needle gauges, check with Steam Machines
if any of their Legacy Sale Supply is left over.
Tip: Buy as much as you can, you'll need it in the long run.

For MK schematics they, Juergensen Marine or Sub Sea Systems may be able to help.

Corallaro · 29th March 2007, 14:57

Hi

in the prism and mk15 the secondary analog display is used to test the output of the cells and the level of battery

there is one microamperometer and a swithch .. to switch fro 1 to 3 cell and to battery

the cells have an high output and require low load.... 25 mv in air

it is all i know...

i dont found the correct milliamperometer..

HELPPPPPPPPPPPPPPPPPPPPPPP

Giovanni

***caveseeker7*** · 29th March 2007, 15:29

Correct, except on the PRISM there is also an 'S' for Setpoint.

Have you had a look at these from Sub Sea Systems.
Digital, very good feedback, available for high output (MK) and normal (Kiss/Inspo etc) cells.

Corallaro · 29th March 2007, 15:50

uaaaaaaaaaaaaaaaa

i wont my analog old style display for my IDA-71!!!!

i think that the analog design is more correct for my IDA-71!!!

and will test a "no battery" display

Giovanni

paulraymaekers · 29th March 2007, 16:44

Quote: (Originally Posted by Corallaro)

uaaaaaaaaaaaaaaaa

i wont my analog old style display for my IDA-71!!!!

i think that the analog design is more correct for my IDA-71!!!

and will test a "no battery" display

Giovanni

why for God sake (?? :-) does every-one try to build a non-reliable 'no-battery' system for cell-reading, while the simple 'DPM with battery' are sheaper, more reliable, easier to find, more accurate.. etc etc etc

I understand why not everybody can program PICs, and use opamps, but simple components like DPM's: if you can make analog circuits, you can use these

there is a reason why new technologie replaces old technologie !

paul

28th March 2007, 21:56	#11 (permalink)
Corallaro IDA-71,IDA-76,NaubosAR90 Current Rebreather/s: Other CCR Other Rebreather/s: Not Bought Yet Other CCR Join Date: Oct 2006 Location: Italia - Sicilia Posts: 248	Re: Homemade PO2 meter Hi Marek ...see this link PO2PCB if you send an email to Dan .. it send you complete electric scheme Giovanni
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29th March 2007, 03:59	#12 (permalink)
marekm Banned Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Oct 2006 Location: Brisbane, Australia Posts: 196	Re: Homemade PO2 meter Hi guys, Thanks for the links, but I have studied those pages months ago and found they both rely on integrated circuits. However, I'm looking for a fully analog way of measuring the millivolts coming out of the O2 cells. Cheeers. -Marek
(Offline)

29th March 2007, 07:49	#13 (permalink)
PeteS Consent Issued! Current Rebreather/s: Inspiration Classic Inspiration Vision Other Rebreather/s: Join Date: Jun 2005 Location: New Zealand Posts: 543	Re: Homemade PO2 meter Quote: (Originally Posted by marekm) Thanks for the links, but I have studied those pages months ago and found they both rely on integrated circuits. However, I'm looking for a fully analog way of measuring the millivolts coming out of the O2 cells. I assume that by "analogue" you mean "discrete components"? After all, not all IC's are digital, and I've worked on digital systems made up from discrete components! In my experience, IC's will make the design work simpler, and the unit more reliable. So why use discrete components? Why not IC based Op-Amps? Or even a MicroPIC with A-D inputs and multiple 16 bit outputs to drive the LED's? I don't think there is anything wrong in your approach, you just seem to be doing it the hard way. The use of an acrylic tube for the display is nicely executed though. I built a similar one some years ago with a vibration sensing switch that fired up the electronics when the tube was tapped, and then shut down 20 seconds later. __________________ Pete S. http://www.steggle.co.nz Every silver lining has a cloud
(Offline)

29th March 2007, 14:34	#15 (permalink)
marekm Banned Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Oct 2006 Location: Brisbane, Australia Posts: 196	Re: Homemade PO2 meter Hi PeteS, Fristly, thankyou for correcting my spelling of analogue . The point of building my own PO2 meter from scratch is to avoid the black box scenario I've currently got with off the shelf DPM's. Throwing in IC brings me back to the black box scenario I am in now. Also, this is just and idea, and time will tell if it is a bad one. In the mean time, I would also like to build a batteryless PO2 meter, but don't know how the PRISM one works, so I don't know how to go about it yet. Cheers. -Marek
(Offline)

29th March 2007, 14:48	#16 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,556	Re: Homemade PO2 meter The analog gauges of the MK and PRISM run directly off the sensors. Don't know the inside of the gauges though, never cracked one open. They're supposed to do that themselves I believe. Seriously though, the drawback of needle gauges are that they are prone to shock/impact damage. You might want to look into some digital option, many MK and PRISM divers are. If however you're set on needle gauges, check with Steam Machines if any of their Legacy Sale Supply is left over. Tip: Buy as much as you can, you'll need it in the long run. For MK schematics they, Juergensen Marine or Sub Sea Systems may be able to help. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
(Offline)

29th March 2007, 14:57	#17 (permalink)
Corallaro IDA-71,IDA-76,NaubosAR90 Current Rebreather/s: Other CCR Other Rebreather/s: Not Bought Yet Other CCR Join Date: Oct 2006 Location: Italia - Sicilia Posts: 248	Re: Homemade PO2 meter Hi in the prism and mk15 the secondary analog display is used to test the output of the cells and the level of battery there is one microamperometer and a swithch .. to switch fro 1 to 3 cell and to battery the cells have an high output and require low load.... 25 mv in air it is all i know... i dont found the correct milliamperometer.. HELPPPPPPPPPPPPPPPPPPPPPPP Giovanni
(Offline)

29th March 2007, 15:29	#18 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,556	Re: Homemade PO2 meter Correct, except on the PRISM there is also an 'S' for Setpoint. Have you had a look at these from Sub Sea Systems. Digital, very good feedback, available for high output (MK) and normal (Kiss/Inspo etc) cells. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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29th March 2007, 15:50	#19 (permalink)
Corallaro IDA-71,IDA-76,NaubosAR90 Current Rebreather/s: Other CCR Other Rebreather/s: Not Bought Yet Other CCR Join Date: Oct 2006 Location: Italia - Sicilia Posts: 248	Re: Homemade PO2 meter uaaaaaaaaaaaaaaaa i wont my analog old style display for my IDA-71!!!! i think that the analog design is more correct for my IDA-71!!! and will test a "no battery" display Giovanni
(Offline)

29th March 2007, 16:44	#20 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,638	Re: Homemade PO2 meter Quote: (Originally Posted by Corallaro) uaaaaaaaaaaaaaaaa i wont my analog old style display for my IDA-71!!!! i think that the analog design is more correct for my IDA-71!!! and will test a "no battery" display Giovanni why for God sake (?? :-) does every-one try to build a non-reliable 'no-battery' system for cell-reading, while the simple 'DPM with battery' are sheaper, more reliable, easier to find, more accurate.. etc etc etc I understand why not everybody can program PICs, and use opamps, but simple components like DPM's: if you can make analog circuits, you can use these there is a reason why new technologie replaces old technologie ! paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials... Last edited by paulraymaekers : 29th March 2007 at 16:47.
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