Photos of the insides of Fine Offset sensors.

[aussiewmr]

For those of you that have WH3081 Weather Stations as used most probably in Australia, NZ, UK (EG Non USA) here are some photos of the Outdoor and Solar / Lux Sensors.

From what I can see the Wind Sensors are the same as those posted earlier in this thread.

The solar sensor photo here is not the one I modified as per a post here (Solar and UV Sensors going offline - fix?). There is little point posting that because the mod did not fix the issue I was having.

Cheers
Phil

[AllyCat]

Hi Phil,

Thanks for those very detailed pictures; from another thread it seems that you're aware of most of the components, but perhaps it's worth adding the details here.

The Lux sensor is under the white diffuser dome on the right, the microcontroller under the black blob nearby and the UV sensor is a tiny chip at lower left. The 8-pin package near the centre is a small serial flash memory, presumably for Lux/UV lookup tables and perhaps calibration for the specific components.

Personally, I suspect that the UV sensor is a standard UVA+UVB type (the "UV index" is fundamentally UVB) and should be mounted under a UVB-pass filter (which may explain the poor accuracy). Recently, I saw a patent which claimed that UVB could be inferred (calculated) from individual UVA and Visible light measurements but I don't know if this is correct or if FO attempt it.

Just as this solar module first "saw the light of day" purely as a PV cell to charge the transmitter batteries, FO appear have plans to extend its functionality further. The unpopulated area beside the L-shaped slot is obviously for a radio transmitter and I guess some of the pads on the right will accept a daughter-board, perhaps for temperature and humidity sensors. This, together with the pads for two tag-ended batteries (or a holder), could make a complete "external unit" (which might suffer less problems than the present "two-processor" arrangement). A socket for the rain sensor is already fitted so the main unknown is whether the wind vane and/or anemometer would be omitted, or perhaps attached by a "captive" cable from some of the other "spare" pads on the PCB.

Generally, the overall quality of the PCB assembly (soldering, etc.) seems far higher than previous FO units and it must be disappointing (for all concerned) that the current performance and reliability is so poor.

Cheers, Alan.

[aussiewmr]

Hi Alan,

Here's the detail of the light sensor with the diffuser removed. I think it's some sort of Photo Diode rather than the LDR I expected.

Sorry about the focus - its a bit hard to get closeups with the equipment I have.

Phil

[Andyman]

Hi all. The wires in my wind direction sensor have come off. Does anyone have any info on which colour wire goes where?

regards
Andy

[AllyCat]

Hi Andy,

Yes, I encountered the same problem, so I'm not sure of the original connections either. However, as the cable is a ribbon style there are really only two (logical) ways to reconnect the wires. Electrically, it shouldn't matter which way they are connected because the two inner wires go to the anemometer and the two outer ones to the vane. However, the A/D converter driven by the vane resistance is rather sensitive so there might be a subtle difference. Perhaps somebody else knows?

Sometime I'm going to dismantle another vane and will photograph it, but as you (and Gina in her photo earlier in the thread) have discovered the wires are quite fragile (and the adhesion of the tracks on the PCB not too good either) so I'm not going to hurry.

Cheers, Alan.

[ScottM]

This seems to be the Thread of Fine Offset Goodness, so I'm certain someone here knows the answer -

Are the rain gauge, wind speed and wind direction sensors all "Dallas One Wire" based?

I ask because I'm completely and totally fed up with my Ambient WS-2080 - the receiver loses contact with the sensor array routinely, and it's not like the distance between them is great. It's under 100' and there's a single pane of glass between them. I've had Ambient replace the display/receiver - no real improvement.

But now I'm thinking I can buy an inexpensive microprocessor board, a one-wire/USB converter, and write my own code to read wind and rain data. Add a one wire temperature and humidity sensor, and done. Give the microprocessor a USB wifi adapter, and now I have a sensor array data transmitted to my house wifi, which is where I want it anyway.

Feasible? And if the electrical interfaces to the various sensors aren't one-wire, what are they? Many thanks.

[AllyCat]

Hi,

No none of the FO sensors are one-wire.

The cabled sensors are based on magnetic reed switches, one pulse per tip of the rain see-saw, 2 pulses per anemometer rotation and an analogue value (resistance) derived from the rotational position of the vane. The external temperature is obtained from the resistance of a thermistor (or the 3080/1 may use a dedicated chip) and I believe humidity is from a variable-frequency oscillator - all measured by the microcontroller in the "transmitter" unit (which may also have a calibration table in a memory chip).

Most of the sensors work reasonably well (temperature spikes excluded) so IMHO the main problem is with the very low cost wireless modules. If you're lucky, even those can work moderately well, but many don't, certainly not near the maximum specification range.

Cheers, Alan.

[ksangeelee]

... thinking I can buy an inexpensive microprocessor board, a one-wire/USB converter, and write my own code to read wind and rain data. Add a one wire temperature and humidity sensor, and done. Give the microprocessor a USB wifi adapter, and now I have a sensor array data transmitted to my house wifi, which is where I want it anyway.

Feasible? And if the electrical interfaces to the various sensors aren't one-wire, what are they? Many thanks.

Rather than try to intercept at the sensors, you might consider doing it at the RF stage. On my 1080 transmitter, the board was laid out into two halves - sensor-reader and RF transmitter. There were only a few tracks leading to the RF transmitter section of the circuit, so I put a logic analyser on the wires, and sure enough there were signals being sent as regular long and short pulses (hi/lo) on these tracks - 88 bits of data as I recall.

I suspect you could hook up (either directly or via a PIC chip if necessary) something like a Hope-RF module to send similar signals at the frequency and modulation of your receiver (though I don't know how the RF on these units is modulated). Perhaps you can do some digging on the forums or inside your base-station to figure out what the transmitter is speaking to in order to figure out your next step.

As for a microprocessor board to WiF?, A Raspberry-Pi with a WiFi dongle would do the job - again I'd suggest hooking into the RF wires, but you'd need to spend some time decoding the low-level sensor-data format. Raspberry Pi boards should be on general sale within a couple of months.

All good fun, but in my experience, any hacking of devices like this usually takes a lot more effort than I first envisage.

[ScottM]

All good fun, but in my experience, any hacking of devices like this usually takes a lot more effort than I first envisage.

Hrm. Interesting, but it means voiding the warranty in a fundamental way. I want to keep the option of sending this junk back and getting my refund (to help defray the cost of better solutions.)

To reduce clutter on the board, let me move the discussion to
https://cumulus.hosiene.co.uk/viewtopic.p ... 83&e=62283
in Homebuilt.

I'll keep your suggestion in mind, though.

[Darrel]

Gina, very nice photos.
My experience with the vane directions is exactly the same as yours.

To emphasize Gina's comment about the intermediate directions (NNW, WNW ...) being poorly represented, I've attached a plot of the relative probabilities of different directions measured over several days. This is a wind vane from the Ambient WS-2080, which I believe uses the same Fine Offset sensor. As you can see, the chance of a 3-letter cardinal point being indicated is very small - about 3% - compared to the other directions. The system of using 2 adjacent reed switches being closed simultaneously, as an indicator of the intermediate direction, is not working very well. If it were possible to use a stronger magnet, or to move the magnet closer to the circuit board, it might be possible to equalize the direction probabilities.
Thanks,
Darrel.

[AllyCat]

Hi Darrel,

Welcome to the forum and yes, the vane directional uniformity can be improved considerably by adding a magnet (or two). But the vane needs to be pulled from its bearing to fit it, see this thread from a few months ago. However, I'm now working on a related project which might achieve a similar result by processing the vane data "in software".

Cheers, Alan.

[Gina]

Magnetic sensing has it's problems. The reed relays vary in sensitivity and they open and close at different distances (angles) from the magnet. I spent a considerable time experimenting with a magnet and a set of 8 or 16 reed relays when I was making my own weather station. There was no way I could get proper in-between readings for the 8 reed switches and the result varied with which way the vane was turning.

I wanted to measure wind direction to a resolution of 16 compas points. I also wanted a more stable vane as the one on the Fine Offset stations swung all over the place.

I solved the resolution problem in my 1-wire station my using light sensors instead of magnetic. I used a Gray encoded disc attached to the vane and 4 LED and phototransistor sensors fed to a 4 input 1-wire chip. And I much reduced the swinging about using an aluminium saucepan lid and high power magnet to provide damping.

I stuck with magnet and reed relay for the anemometer which is almost exactly like the FO sensor. Similarly with the rain gauge but the other sensors are totally different from the FO ones.

[Rinie]

... thinking I can buy an inexpensive microprocessor board, a one-wire/USB converter, and write my own code to read wind and rain data. Add a one wire temperature and humidity sensor, and done. Give the microprocessor a USB wifi adapter, and now I have a sensor array data transmitted to my house wifi, which is where I want it anyway.

Feasible? And if the electrical interfaces to the various sensors aren't one-wire, what are they? Many thanks.

Rather than try to intercept at the sensors, you might consider doing it at the RF stage. On my 1080 transmitter, the board was laid out into two halves - sensor-reader and RF transmitter. There were only a few tracks leading to the RF transmitter section of the circuit, so I put a logic analyser on the wires, and sure enough there were signals being sent as regular long and short pulses (hi/lo) on these tracks - 88 bits of data as I recall.

...
As for a microprocessor board to WiF?, A Raspberry-Pi with a WiFi dongle would do the job - again I'd suggest hooking into the RF wires, but you'd need to spend some time decoding the low-level sensor-data format. Raspberry Pi boards should be on general sale within a couple of months.

All good fun, but in my experience, any hacking of devices like this usually takes a lot more effort than I first envisage.

This has been done. Receiving with a Raspberry Pi + RFM12B, or a Jeelink is described at
http://jeelabs.net/boards/6/topics/1203
and
http://www.raspberrypi.org/phpBB3/viewt ... 37&t=14777
And
http://www.sevenwatt.com/main/wh1080-protocol-v2-fsk/

Code for Jeelink (Arduino with RFM12B) is also at
https://github.com/rinie/weatherstationFSK original in http://jeelabs.net/boards/6/topics/1203

[AllyCat]

Hi,

Welcome to the forum and thanks for those links (which will take me some time to digest in detail).

However, I believe that the following quote from several of the threads is "misleading":

"The Fine Offset weather station switched over to a new RF transmission protocol somewhere in 2012. While the old protocol was a On-Off-Keying (OOK) protocol, the V2 protocol used Frequency-Shift-Keying (FSK). "

As far as I can discover, FO still produce various models using both OOK and FSK and have done so for some years. My "evidence" for this is that my "Clas Ohlson" WH1080 purchased in 2011 appears to use FSK, whilst a very recent "Maplin" transmitter (purchased a few weeks ago) uses OOK. Furthermore, my "old" Maplin WH1080 (c2010) appears to use FSK, whilst the "new" protocol, described by Kevin above (and confirmed by examination of my recent Maplin purchase), is OOK. So the "Maplin" versions appear to have changed from FSK to OOK.

Also, the "Solar" versions (WH3080/1) so far appear to use OOK, since I've sucessfully decoded the three data packet formats ("Normal", "Solar" and "Timecode") using a simple OOK receiver. Incidentally, a Raspberry Pi or Arduino is almost "overkill", I'm simply using a PICaxe chip which cost around £2 and runs off a couple of AA cells.

Cheers, Alan.

[jim-easterbrook]

As far as I can discover, FO still produce various models using both OOK and FSK and have done so for some years. My "evidence" for this is that my "Clas Ohlson" WH1080 purchased in 2011 appears to use FSK, whilst a very recent "Maplin" transmitter (purchased a few weeks ago) uses OOK. Furthermore, my "old" Maplin WH1080 (c2010) appears to use FSK, whilst the "new" protocol, described by Kevin above (and confirmed by examination of my recent Maplin purchase), is OOK. So the "Maplin" versions appear to have changed from FSK to OOK.

Interesting. Is there an easy way to tell the variants apart?

I suspect that the "USB lockup" problem may be related to these changes. It seems it just did not exist until a couple of years ago.