Depth sensor

**UWSojourner** · 26th October 2005, 21:37

Does anyone know the part numbers/manufacturers for the depth sensors going into dive computers (e.g. VR3)? Any info would be appreciated.

Thanks

AD_ward9 · 26th October 2005, 23:53

Quote: (Originally Posted by UWSojourner)

Does anyone know the part numbers/manufacturers for the depth sensors going into dive computers (e.g. VR3)? Any info would be appreciated.

Thanks

I cannot comment on the VR3, but the usual ones being designed into dive kit for sports depth ranges (0 to 140m) are the devices in the family described by the attached datasheet: temperature compensated, all in one, cheap, linear, accurate to 14bits. If you go to the manufacturer´s site, there are quite a few others, but mostly lower FSD.

For high pressure sensors, things are messier. Usually a preformed drumskin with concentric stress rings to keep out the water, then a strain gauge type sensor underneath. I have been sectioning a range of tank contents monitors recently, and found nothing remarkable. Everything from Dacor onwards. Little changes on that front.

Cheers,
Alex

**UWSojourner** · 27th October 2005, 02:14

Quote: (Originally Posted by AD_ward9)

... Usually a preformed drumskin with concentric stress rings to keep out the water, then a strain gauge type sensor underneath.

Uh ... ok.

Any further elaboration on that would help. But in general that approach is only for dives exceeding 400-500ft? Thanks.

***jradomski*** · 27th October 2005, 04:44

Quote: (Originally Posted by UWSojourner)

Does anyone know the part numbers/manufacturers for the depth sensors going into dive computers (e.g. VR3)? Any info would be appreciated.

Thanks

the vr3 pressure sensor is (I id's a long time ago by taking a unit apart) the one that was linked by ad_ward9

its a 14bar absolute sensor.. that means its only rated to 130m

The datasheet is quite old that alex posted..

go to www.intersema.com

The lastest datasheet is only about 1 month old..

Nad · 27th October 2005, 09:27

This is a Swiss company

(we don't have just cheese, chocolate and watches

).

They said that the sensor will still function up to approx. 19 bars with reduced accuracy. Above this the ADC will go into saturation.
The burst pressure will be around 70 bars.

I would be interesting to know how much is reduced the accuracy...

Nad

***jradomski*** · 27th October 2005, 10:27

Quote: (Originally Posted by Nad)

This is a Swiss company

(we don't have just cheese, chocolate and watches

).

They said that the sensor will still function up to approx. 19 bars with reduced accuracy. Above this the ADC will go into saturation.
The burst pressure will be around 70 bars.

I would be interesting to know how much is reduced the accuracy...

Nad

The actual functioning depth is going to be dependent on the individual offset within the sensor and its temperature coeff and sensitivity.. My calculations using some of the sample numbers rpovided by intersema show that its not unreasonable to see the sensor max out around 23.8 bar or 228m

colder water will extend this somewhat..

***USSMEG*** · 27th October 2005, 11:57

While @ Cis-Lunar we got them from a smaller branch of Oceanic, called Pelagic. See if you can talk to someone there? I believe they were both in southern Calif.
Later Paul

***jradomski*** · 27th October 2005, 12:14

Quote: (Originally Posted by USSMEG)

While @ Cis-Lunar we got them from a smaller branch of Oceanic, called Pelagic. See if you can talk to someone there? I believe they were both in southern Calif.
Later Paul

The company that actually suppliesPelagic Pressure Systems is SMI (silicon microstructures inc).

Here is their web link
http://www.si-micro.com/products1.html

**UWSojourner** · 28th October 2005, 02:12

Thanks for the info links. I've got enough to chew on for awhile.

AD_ward9 · 9th November 2005, 01:44

Quote: (Originally Posted by UWSojourner)

Uh ... ok.

Any further elaboration on that would help. But in general that approach is only for dives exceeding 400-500ft? Thanks.

By higher pressure I meant contents gauges rather than deeper dives.

We use an integrated very high pressure sensor for contents gauges, the data sheet is attached, but from the sectioning work, not many others do.

We sectioned another Dacor sensor, and it does use a micromachined structure for contents applications. So they seem to have two models, (or someone was a bit energetic with the grinder and lost the chip first time - can happen).

Cheers
Alex

26th October 2005, 21:37	#1 (permalink)
UWSojourner Pacific Northwest Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Portland Oregon Posts: 558	Depth sensor Does anyone know the part numbers/manufacturers for the depth sensors going into dive computers (e.g. VR3)? Any info would be appreciated. Thanks
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27th October 2005, 02:14	#3 (permalink)
UWSojourner Pacific Northwest Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Portland Oregon Posts: 558	Re: Depth sensor Quote: (Originally Posted by AD_ward9) ... Usually a preformed drumskin with concentric stress rings to keep out the water, then a strain gauge type sensor underneath. Uh ... ok. Any further elaboration on that would help. But in general that approach is only for dives exceeding 400-500ft? Thanks.
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27th October 2005, 04:44	#4 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,113	Re: Depth sensor Quote: (Originally Posted by UWSojourner) Does anyone know the part numbers/manufacturers for the depth sensors going into dive computers (e.g. VR3)? Any info would be appreciated. Thanks the vr3 pressure sensor is (I id's a long time ago by taking a unit apart) the one that was linked by ad_ward9 its a 14bar absolute sensor.. that means its only rated to 130m The datasheet is quite old that alex posted.. go to www.intersema.com The lastest datasheet is only about 1 month old.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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27th October 2005, 09:27	#5 (permalink)
Nad Rebel to the Bone Current Rebreather/s: Ouroboros Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Join Date: Mar 2005 Location: Europe Posts: 1,014	Re: Depth sensor This is a Swiss company (we don't have just cheese, chocolate and watches ). They said that the sensor will still function up to approx. 19 bars with reduced accuracy. Above this the ADC will go into saturation. The burst pressure will be around 70 bars. I would be interesting to know how much is reduced the accuracy... Nad __________________ The Impossible is often the Untried
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27th October 2005, 10:27	#6 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,113	Re: Depth sensor Quote: (Originally Posted by Nad) This is a Swiss company (we don't have just cheese, chocolate and watches ). They said that the sensor will still function up to approx. 19 bars with reduced accuracy. Above this the ADC will go into saturation. The burst pressure will be around 70 bars. I would be interesting to know how much is reduced the accuracy... Nad The actual functioning depth is going to be dependent on the individual offset within the sensor and its temperature coeff and sensitivity.. My calculations using some of the sample numbers rpovided by intersema show that its not unreasonable to see the sensor max out around 23.8 bar or 228m colder water will extend this somewhat.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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27th October 2005, 11:57	#7 (permalink)
*USSMEG* USSMEG Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Mar 2005 Location: Mass Posts: 300	Re: Depth sensor While @ Cis-Lunar we got them from a smaller branch of Oceanic, called Pelagic. See if you can talk to someone there? I believe they were both in southern Calif. Later Paul
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27th October 2005, 12:14	#8 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,113	Re: Depth sensor Quote: (Originally Posted by USSMEG) While @ Cis-Lunar we got them from a smaller branch of Oceanic, called Pelagic. See if you can talk to someone there? I believe they were both in southern Calif. Later Paul The company that actually suppliesPelagic Pressure Systems is SMI (silicon microstructures inc). Here is their web link http://www.si-micro.com/products1.html __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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28th October 2005, 02:12	#9 (permalink)
UWSojourner Pacific Northwest Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Portland Oregon Posts: 558	Re: Depth sensor Thanks for the info links. I've got enough to chew on for awhile.
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