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Watson W-8681-Solar

Discussion specific to Fine Offset and similar rebadged weather stations
AllyCat
Posts: 1042
Joined: Sat Feb 26, 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Watson W-8681-Solar

Postby AllyCat » Fri Jun 20, 2014 2:53 pm

Hi,

If I understand you correctly: After pressing the "Down Arrow" button on the Console then all the data is displayed on the LCD, but then after a few minutes (?) the Lux and UV change to dashes?

That would suggest that the crystal oscillator in the Solar Pod is giving an incorrect frequency (i.e. wrong time between transmissions). Can you see the time between each (not very bright) flash of the red LED in front of the PV panel? It should be exactly 60 seconds. One of the "modifications" suggested for the early Pods was to solder the "can" (case) of the crystal to earth (see this long thread concerning issues with the "3081", which is the same model), but I'm not very confident that it will help.

Cheers, Alan.

sergios
Posts: 8
Joined: Sun May 08, 2011 8:14 pm
Weather Station: watson w8681 solar uv
Operating System: Windows XP SP2
Location: Greece

Re: Watson W-8681-Solar

Postby sergios » Fri Jun 20, 2014 4:50 pm

Hello Allan, thanks for the help. So, i press reset from the pod and the down arrow from console. I get dashes lux and uv. So i try to push 30sec reset to pod and 10secs to console. I get it work but after 5minutes i get again dashes. That's means there is a problem from frequency?thanks.

sergios
Posts: 8
Joined: Sun May 08, 2011 8:14 pm
Weather Station: watson w8681 solar uv
Operating System: Windows XP SP2
Location: Greece

Re: Watson W-8681-Solar

Postby sergios » Fri Jun 20, 2014 4:59 pm

I forget to tell that i see from the console that it "try" to find the freq (scan icon) over a minute.
I will take it down tomorrow to see if that causes something else (electricity lines?something rf?), cause when i take it down to clean it before 3 days i change it the location where it was and then the problems starts.

sergios
Posts: 8
Joined: Sun May 08, 2011 8:14 pm
Weather Station: watson w8681 solar uv
Operating System: Windows XP SP2
Location: Greece

Re: Watson W-8681-Solar

Postby sergios » Sat Jun 21, 2014 12:58 pm

Hello, i get it down inside my house to investigate. Works fine as you said Allan, every minute the led from pod turns and every 48secs the led from trnasmitter. I get it back to the old place it was before a week (change location) and works fine. Thanks for the help.

Ham radio Bob
Posts: 3
Joined: Thu Jun 14, 2018 2:51 pm
Weather Station: W-8681-solar
Operating System: w10

Re: Watson W-8681-Solar

Postby Ham radio Bob » Thu Jun 14, 2018 3:10 pm

I had similar problems with the UV and light sensors going off line so I bought another complete system this one has the frosted area over the UV sensor,
Both have exactly the same problem, I have tried all the fixes that have been posted on this site, but none fix it permanently. I have found that in the winter when the ambient temperature is below 10 degrees both sensor units work for weeks on end without problems, but when we get a bit of warm weather whichever one I have in use fails. In the summer when the ambient is above 18 either one will work initially but fail after a few minutes.
I have covered the solar panel, the light and UV sensors with black tape so that the unit thinks it is night time, this also doe=s not work. I came to the conclusion that heat is the problem so I put the sensor in my freezer for about 15 minutes and lo and behold either will work for several hours before failing again when they both fail very quickly without the freezer treatment.
Does anybody on here have circuit diagrams of the Watson 8681 Solar? I am beginning to think that maybe the clock oscillator is the culprit, what frequency should it operate at?

I hope this is of some use to others on here and would like to know how they get on with the Freezer temporary fix.

AllyCat
Posts: 1042
Joined: Sat Feb 26, 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Watson W-8681-Solar

Postby AllyCat » Sat Jun 16, 2018 3:53 pm

Hi,

Welcome to the forum. AFAIK the 8681-Solar Pod is identical to the WH-308x family, so did you look at the long thread I linked at the top of this page? Unfortunately the photos are no longer attached, but it became apparent that there were several different faults with the original Pods. My first Pod flattened the batteries consistently every 3 months, but its replacement worked "moderately" well. It did hang (go offline) occasionally (even with the UV sensor masked), but only every year or two. However, this was not just a "glitch" in the timing but a total lock-up that could be recovered only by a power-down/Reset.

Your Pods do seem particularly "sick", but the problem definitely appeared to be caused by high "Solar" levels, but I could never determine if it was related to UV, Lux, direct heating, PV (battery-charging) overload, or something else. Perhaps I should add (although I don't believe it's significant) that my Pod operates on an extended cable, so that it is "up with the wind sensors", whilst the T/H Transmitter is located in a more shaded location.

I think that the crystal is a standard 32768 Hz "Watch" crystal, so replacing (or earthing) it might help. However, if the Console "loses" the transmissions, then I believe it automatically searches for them again after some (unknown) time (the Chinglish User Manual implies this). But that obviously cannot help if the transmitter glitches as frequently as every few minutes.

I've not seen a "frosted" UV sensor, but the latest version of the Pod has a "3mm through-hole LED" style of package, instead of the original SMD part. The Pod is currently available at quite modest cost presumably because there is not much demand as the associated transmitter and Console are so expensive.

No, I've never seen a circuit diagram but I can give a few hints. The Lux sensing clearly has several "coarse" ranges, the selection of which I've seen fail on two units. The PV panel feeds a 3.3 volt regulator which charges the battery via a Schottky diode so the charging voltage is very close to 3.0 volts. That's rather high for 2 x NiMH cells and too low for 2 x NiZn cells or a single Lithium Phosphate (LiFePO4), nominally 3.2 volts, and arguably not really enough for those horrible, supplied "Rechargeable Alkalines". I've never ascertained what the "Reset" button/connection actually does, but it is clear that the Pod and Transmitter communicate such that their signals always "interleave" (i.e. are never less than a few seconds apart).

Cheers, Alan.

Ham radio Bob
Posts: 3
Joined: Thu Jun 14, 2018 2:51 pm
Weather Station: W-8681-solar
Operating System: w10

Re: Watson W-8681-Solar

Postby Ham radio Bob » Fri Aug 03, 2018 12:52 pm

Hi Alan,
Thank you for the info, I have ordered another pod from the site you suggested, I will then have 4, two are showing both UV and Lux but fail after 10's of minutes after freezing, power down completely(batteries out and solar pod disconnected) and one that has a faulty UV detector SMD detector chip the Lux works OK. I did attempt to replace this with a solar detector intended for use with a RasberryPi, I bought it on ebay, desoldered the chip and put it in the solar pod but it is too sensitive and the UV display now reads >12 falling to 12 when masked with black tape! If I could find either the manufacturer so that I can contact them for the necessary info or find the chip type, there are no markings on the SMD chip (the rasberryPi one looks identical) I would get that one working too.

Cheers

Bob

AllyCat
Posts: 1042
Joined: Sat Feb 26, 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Watson W-8681-Solar

Postby AllyCat » Sat Aug 04, 2018 3:51 pm

Hi,

IIRC the FO Solar Pod has a ROM chip on the PCB which probably contains calibration data. So even if you could identify the "correct" sensor chips, would not necessarily guarantee "good" (accurate) results.

I won't get onto my hobby horse again in detail here, but IMHO the FO Solar Pod does not use sensors which give "correct" values for either the true "UV Index" (primarily UVB) nor "Lux" (visible light peaking in the green). Most photodiodes measure the "visible + near IR" part of the spectrum, which is actually what is required for a watts/m2 measurement (but not Lux).

Cheers, Alan.

Ham radio Bob
Posts: 3
Joined: Thu Jun 14, 2018 2:51 pm
Weather Station: W-8681-solar
Operating System: w10

Re: Watson W-8681-Solar

Postby Ham radio Bob » Sun Aug 12, 2018 9:23 am

Hi Alan,

Thanks for the heads up on the version 3 solar pod available on ebay. I bought one and it appears to have cured my problem, the UV and lux displays have been showing for over a week now which is unprecedented, both of the other solar pods obviously have problems which cause the readings to fail within a very short time.

Many thanks again

Bob


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