Very Small Panel Meters

undrh2o · 6th January 2008, 00:21

Quote: (Originally Posted by OceanOpportunity)

wow..the munro version 6 is TINY! anyone out there producing short runs of assembled units for the folks like me who are less than skilled working with boards?

The soldering is super simple - it's the housing that is the problem for me (no access to cheap machining) - I might have something worked out in the next month or so for that though.

DanFountain · 8th January 2008, 02:02

Quote: (Originally Posted by rchrds)

Dan- yes, that is one of Mark's old boards. Date on it is 2000- which
is probably the last time I really worked hard on the unit. Anyway, it works pretty well,
but I hate the size of the housing. I was going exactly the direction you were with the
smaller displays- was looking at the Martel OEM 1B model- very small- perhaps about the
size of the ones you have in your picture?

Those are the same Datel meters that Mark Munro uses - I just filed off the flange on the
top and bottom to get them to fit closer together (saved 0.2"!)

Quote: (Originally Posted by OceanOpportunity)

wow..the munro version 6 is TINY! anyone out there producing
short runs of assembled units for the folks like me who are less than skilled working with
boards?

Mark's boards really are pretty user-friendly - no surface mount stuff or opening the
meter.

Quote: (Originally Posted by teomannaskali)

Now with the setup that I have made. 2 ppo2 displays inside the
same housing. I have option 2. How can I upgrade to option 3. Use 2 of the same ppo2
displays? I would have to leave out the 10K resistors on one set of displays.
But If I have a flood then what? If the flood shorts the cell on the other side then it is
useless to have independant dual ppo2 displays! Is there an way of doing this? If I
completely potted the lines to the display maby? how does the DPM behave when it is
flooded?

I haven't tested this yet, but a simple resistor isolator should work fine with such low
currents. 10K resistor across each cell output (R1, R2, R3), then 100K or so in series with each meter
input (R4-R9).

I built one on a scrap of perf board, then potted it in epxoy in a 35 mm film can
so it can live outside the loop (only one cable gland thru the head!)

Quote: (Originally Posted by underh2o)

The soldering is super simple - it's the housing that is the problem for me (no access to cheap machining) - I might have something worked out in the next month or so for that though.

Mark's Gen Six-3 will fit in an OMS tube; you can cut the tube in half, glue on end caps, and have two housings for Gen Six-2 meters (or my modified layout of Mark's Gen Six-3). No machining needed, just a hacksaw, epoxy and a drill.

-Dan

undrh2o · 8th January 2008, 20:24

Looks good Dan - quick question what do you use for cables?

DanFountain · 9th January 2008, 12:03

Quote: (Originally Posted by undrh2o)

Looks good Dan - quick question what do you use for cables?

It's Continuous-Flex Multiconductor Cable from McMaster-Carr. 7673K57, as I recall. (Thanks, Bnsherm!)

Dan

Fulefejs · 14th January 2008, 19:16

Hi

Lending thread for a quick question...

Will this work? Why not?

teomannaskali · 14th January 2008, 19:52

Why do you have a 100k Pot? I use 2.2K on my sp400
First calculate the gain you need with your batterie and the high and low outputs of the cell. And from that determine your resistance values.
For me they were 700 ohms and 2.2K ohms. So I got away with using only 1 pot. But 100K is a very large range. So what you might want to do is put for example 90K resistance and a 10K mutli turn pot... You have to calcualte the values.

And the link between COM and INL why do you want the ground between the battery and the cell to be common?

Ps. in future please also post a link to the data sheet. It would be more convenient to quickly access it.

Teoman

6th January 2008, 00:21	#71 (permalink)
undrh2o Chris Miller Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Inspiration Classic Other CCR Dolphin Home Build Join Date: Apr 2006 Location: Ottawa, Canada Posts: 206	Re: Very Small Panel Meters Quote: (Originally Posted by OceanOpportunity) wow..the munro version 6 is TINY! anyone out there producing short runs of assembled units for the folks like me who are less than skilled working with boards? The soldering is super simple - it's the housing that is the problem for me (no access to cheap machining) - I might have something worked out in the next month or so for that though.
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8th January 2008, 02:02	#72 (permalink)
DanFountain This is my custom title! Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Dec 2005 Location: Lake Superior Posts: 113	Re: Very Small Panel Meters Quote: (Originally Posted by rchrds) Dan- yes, that is one of Mark's old boards. Date on it is 2000- which is probably the last time I really worked hard on the unit. Anyway, it works pretty well, but I hate the size of the housing. I was going exactly the direction you were with the smaller displays- was looking at the Martel OEM 1B model- very small- perhaps about the size of the ones you have in your picture? Those are the same Datel meters that Mark Munro uses - I just filed off the flange on the top and bottom to get them to fit closer together (saved 0.2"!) Quote: (Originally Posted by OceanOpportunity) wow..the munro version 6 is TINY! anyone out there producing short runs of assembled units for the folks like me who are less than skilled working with boards? Mark's boards really are pretty user-friendly - no surface mount stuff or opening the meter. Quote: (Originally Posted by teomannaskali) Now with the setup that I have made. 2 ppo2 displays inside the same housing. I have option 2. How can I upgrade to option 3. Use 2 of the same ppo2 displays? I would have to leave out the 10K resistors on one set of displays. But If I have a flood then what? If the flood shorts the cell on the other side then it is useless to have independant dual ppo2 displays! Is there an way of doing this? If I completely potted the lines to the display maby? how does the DPM behave when it is flooded? I haven't tested this yet, but a simple resistor isolator should work fine with such low currents. 10K resistor across each cell output (R1, R2, R3), then 100K or so in series with each meter input (R4-R9). I built one on a scrap of perf board, then potted it in epxoy in a 35 mm film can so it can live outside the loop (only one cable gland thru the head!) Quote: (Originally Posted by underh2o) The soldering is super simple - it's the housing that is the problem for me (no access to cheap machining) - I might have something worked out in the next month or so for that though. Mark's Gen Six-3 will fit in an OMS tube; you can cut the tube in half, glue on end caps, and have two housings for Gen Six-2 meters (or my modified layout of Mark's Gen Six-3). No machining needed, just a hacksaw, epoxy and a drill. -Dan __________________ Try not. Do - or do not. There is no try. -Yoda Last edited by DanFountain : 8th January 2008 at 12:15. Reason: Added pics.
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8th January 2008, 20:24	#73 (permalink)
undrh2o Chris Miller Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Inspiration Classic Other CCR Dolphin Home Build Join Date: Apr 2006 Location: Ottawa, Canada Posts: 206	Re: Very Small Panel Meters Looks good Dan - quick question what do you use for cables?
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9th January 2008, 12:03	#74 (permalink)
DanFountain This is my custom title! Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Dec 2005 Location: Lake Superior Posts: 113	Re: Very Small Panel Meters Quote: (Originally Posted by undrh2o) Looks good Dan - quick question what do you use for cables? It's Continuous-Flex Multiconductor Cable from McMaster-Carr. 7673K57, as I recall. (Thanks, Bnsherm!) Dan __________________ Try not. Do - or do not. There is no try. -Yoda
(Offline)

14th January 2008, 19:52	#76 (permalink)
teomannaskali RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Feb 2006 Location: Istanbul TR Posts: 421	Re: Very Small Panel Meters Why do you have a 100k Pot? I use 2.2K on my sp400 First calculate the gain you need with your batterie and the high and low outputs of the cell. And from that determine your resistance values. For me they were 700 ohms and 2.2K ohms. So I got away with using only 1 pot. But 100K is a very large range. So what you might want to do is put for example 90K resistance and a 10K mutli turn pot... You have to calcualte the values. And the link between COM and INL why do you want the ground between the battery and the cell to be common? Ps. in future please also post a link to the data sheet. It would be more convenient to quickly access it. Teoman
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