While on DS1302 RTC Accuracy...
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>
Original Message
> From: Chris Loiacono [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=o6tLfMwijIZjim98YxCZ6G16OnorP0yjtDx7JsZnGKpcHB7bsouFpUKwVjVMl0ShwrtAWZXpYun0]chris@m...[/url
> Sent: Friday, January 04, 2002 11:04 AM
> To: 'basicstamps@yahoogroups.com'
> Subject: RE: [noparse][[/noparse]basicstamps] While on DS1302 RTC Accuracy...
>
>
> Since we're on the subject,
>
> I added a DS1302 to a project as an after thought. When I
> first put it on the board, the RTC statements were rem'ed
> out, as I wanted to first test a separate input by itself.
> This is an in-water device, and on one of those early tests,
> the case seal was compromised, letting some water in. The
> DS1302 and it's crystal were the only things to get wet.
>
> Now that I have resolved the case issue and want to test the
> entire device, the 1302 seems to be working, but it stays at
> the 00:00:00 start time I wrote. I was wondering if those
> small $.50 cylindrical crystals are particularly sensitive to
> water. My thinking is that without the crystal functioning,
> the Stamp would repeatedly read the initial zero's.
>
> I'm trying to decide whether to change the crystal, or keep
> re-checking my code, which is much easier. BTW, I can't get a
> scope probe on the crystal when it's powered due to the way
> the device is assembled...so I really can't tell if it's
> clocking without doing total dissection. What do you crystal
> experts have to enlighten me before I proceed?
>
> Chris
>
Original Message
> From: Chris Loiacono [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=o6tLfMwijIZjim98YxCZ6G16OnorP0yjtDx7JsZnGKpcHB7bsouFpUKwVjVMl0ShwrtAWZXpYun0]chris@m...[/url
> Sent: Friday, January 04, 2002 11:04 AM
> To: 'basicstamps@yahoogroups.com'
> Subject: RE: [noparse][[/noparse]basicstamps] While on DS1302 RTC Accuracy...
>
>
> Since we're on the subject,
>
> I added a DS1302 to a project as an after thought. When I
> first put it on the board, the RTC statements were rem'ed
> out, as I wanted to first test a separate input by itself.
> This is an in-water device, and on one of those early tests,
> the case seal was compromised, letting some water in. The
> DS1302 and it's crystal were the only things to get wet.
>
> Now that I have resolved the case issue and want to test the
> entire device, the 1302 seems to be working, but it stays at
> the 00:00:00 start time I wrote. I was wondering if those
> small $.50 cylindrical crystals are particularly sensitive to
> water. My thinking is that without the crystal functioning,
> the Stamp would repeatedly read the initial zero's.
>
> I'm trying to decide whether to change the crystal, or keep
> re-checking my code, which is much easier. BTW, I can't get a
> scope probe on the crystal when it's powered due to the way
> the device is assembled...so I really can't tell if it's
> clocking without doing total dissection. What do you crystal
> experts have to enlighten me before I proceed?
>
> Chris
>
Comments
> > DS1302 and it's crystal were the only things to get wet.
> >
> > Now that I have resolved the case issue and want to test the
> > entire device, the 1302 seems to be working, but it stays at
> > the 00:00:00 start time I wrote. I was wondering if those
> > small $.50 cylindrical crystals are particularly sensitive to
> > water. My thinking is that without the crystal functioning,
> > the Stamp would repeatedly read the initial zero's.
Hi Chris,
My initial guess would be some residual water deposit or corrosion
between the pins or underneath something. Maybe a wash with
isopropyl could clean and dry it. How do you know it is working? I
think (untested) that even without the crystal operating, you should
be able to write and read to the registers, both the time registers
and the ram registers. Did you have your clock code working before
the accident?
-- Tracy
> days, perhaps a week since the device got wet in clear fresh
> water, and I let it air-dry since. I'll try a good alcohol
When dinosaurs roamed the Earth, I designed a leak detection system for
the Strategic Petroleum Reserve that detected leaks of the brine being
pumped out of the domes. When a seal would break we would get a 1000 PSI
intrusion of salt brine.
Here's what we would do. Disassemble as much as possible and sponge off
what you can. Then put the thing in a bel jar and pump the air out of
it. You don't need a very high vac, just enough to lower the air
pressure. The boiling point of water drops as the pressure drops, so if
you get the pressure low enough, the water boils off at room
temperature. Wash down in DI water to get rid of the salt residue and
repeat the "boiling" step. Ready to go again.
Al Williams
AWC
* Floating point A/D
http://www.al-williams.com/awce/pak9.htm
I can evidently write and read to and from the time registers, since I wrote
zeros to them and they appear to be serout'ing 00:00:00 to the display (BTW,
Scott Edwards 2 X 16 unit survived the wet-test without a hitch)I guess it
can power-on all 0's, can't it? So, I may be wrong...
It's been days, perhaps a week since the device got wet in clear fresh
water, and I let it air-dry since. I'll try a good alcohol wash anyway. I
never did see the clock code working before hand. The whole thing has to be
in the water to start the process. It's not that complex of a circuit, so I
may just set it up on the breadboard to see if the clock code. I suppose I
can dummy the variable that tells the Stamp it's in the water...
Good basic troubleshooting logic!
Thanks Tracy
ps:
One of these days, I'll get back to the TI MPS low-power chips. The Dev kit
for the one I wanted was a BIT more expensive, but eventually, I won't be
able to avoid it...
I'm playing with a low-power cell-phone type display w/ COF serial
controller also, but I haven't had the time to get it working with a Stamp
yet....Will let you know how these eventually work out.
Chris
> My initial guess would be some residual water deposit or corrosion
> between the pins or underneath something. Maybe a wash with
> isopropyl could clean and dry it. How do you know it is working? I
> think (untested) that even without the crystal operating, you should
> be able to write and read to the registers, both the time registers
> and the ram registers. Did you have your clock code working before
> the accident?
>
> -- Tracy
>
"When dinosaurs roamed the Earth, I designed a leak detection system for the
Strategic Petroleum Reserve that detected leaks of the brine being pumped
out of the domes. When a seal would break we would get a 1000 PSI intrusion
of salt brine. "
Hmn,
Just before the dinosoars appeared I solved a problem for civilian remote
piloted submarines. We needed to detect ingress of water - which happened on
every journey.
I tried various ideas, but nothing was reliable. We even took a ballcock out
of the staff washroom and wired it to a microswitch - not sensitive enough.
The solution came to me the day after a party whilst dropping some soluble
aspirin into a glass.
The solution? We put a soluble aspirin between the jaws of a spring loaded
washing peg with stainless steel shims glued to the jaws. When water came
in, the aspirin dissolved, the jaws shut and closed a cct to bring the sub
up to the surface.
Worked every time... Since then I've heard others have used the same trick
for similar jobs, maybe they went to the same party...
Regards,
Tony Wells
Original Message
From: "Al Williams" <alw@a...>
To: <basicstamps@yahoogroups.com>
Sent: Saturday, January 05, 2002 2:49 AM
Subject: RE: FW: [noparse][[/noparse]basicstamps] While on DS1302 RTC Accuracy...
> > So, I may be wrong... It's been
> > days, perhaps a week since the device got wet in clear fresh
> > water, and I let it air-dry since. I'll try a good alcohol
>
>
> Here's what we would do. Disassemble as much as possible and sponge off
> what you can. Then put the thing in a bel jar and pump the air out of
> it. You don't need a very high vac, just enough to lower the air
> pressure. The boiling point of water drops as the pressure drops, so if
> you get the pressure low enough, the water boils off at room
> temperature. Wash down in DI water to get rid of the salt residue and
> repeat the "boiling" step. Ready to go again.
>
> Al Williams
> AWC
> * Floating point A/D
> http://www.al-williams.com/awce/pak9.htm
>
>
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>
freezers. A little more low tech -- the one I saw had foil around the
jaws. Maybe an Alka-Seltzer would be more efficacious (sorry -- a very
bad pun on effervescent).
Al Williams
AWC
* New Kit: Need a 5V supply?
http://www.al-williams.com/awce/ps1.htm
>
Original Message
> From: tony.wells@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=_43NSASPCRtSdL_kYQuRZBtdEi6fvsc5ITQ0msMOvPfh3iRTfa7WWFkOOnTYnaDpSh0_A20Iff4bEhKf_71jGA]tony.wells@a...[/url
> Sent: Friday, January 04, 2002 9:06 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: FW: [noparse][[/noparse]basicstamps] While on DS1302 RTC Accuracy...
>
>
> Al Williams wrote:
>
> "When dinosaurs roamed the Earth, I designed a leak detection
> system for the Strategic Petroleum Reserve that detected
> leaks of the brine being pumped out of the domes. When a seal
> would break we would get a 1000 PSI intrusion of salt brine. "
>
> Hmn,
>
> Just before the dinosoars appeared I solved a problem for
> civilian remote piloted submarines. We needed to detect
> ingress of water - which happened on every journey.
>
> I tried various ideas, but nothing was reliable. We even took
> a ballcock out of the staff washroom and wired it to a
> microswitch - not sensitive enough. The solution came to me
> the day after a party whilst dropping some soluble aspirin
> into a glass.
>
> The solution? We put a soluble aspirin between the jaws of a
> spring loaded washing peg with stainless steel shims glued to
> the jaws. When water came in, the aspirin dissolved, the jaws
> shut and closed a cct to bring the sub up to the surface.
>
> Worked every time... Since then I've heard others have used
> the same trick for similar jobs, maybe they went to the same party...
>
> Regards,
>
> Tony Wells
>
>
Original Message
> From: "Al Williams" <alw@a...>
> To: <basicstamps@yahoogroups.com>
> Sent: Saturday, January 05, 2002 2:49 AM
> Subject: RE: FW: [noparse][[/noparse]basicstamps] While on DS1302 RTC Accuracy...
>
>
> > > So, I may be wrong... It's been
> > > days, perhaps a week since the device got wet in clear
> fresh water,
> > > and I let it air-dry since. I'll try a good alcohol
> >
> >
> > Here's what we would do. Disassemble as much as possible and sponge
> > off what you can. Then put the thing in a bel jar and pump
> the air out
> > of it. You don't need a very high vac, just enough to lower the air
> > pressure. The boiling point of water drops as the pressure
> drops, so
> > if you get the pressure low enough, the water boils off at room
> > temperature. Wash down in DI water to get rid of the salt
> residue and
> > repeat the "boiling" step. Ready to go again.
> >
> > Al Williams
> > AWC
> > * Floating point A/D http://www.al-williams.com/awce/pak9.htm
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in
> the Subject
> > and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
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> Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
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