Modifying the WH1081 Weather Station – Part 1

[Failed – So, this didn’t work as expected. In fact this didn’t make one single iota of difference – Post left here just for reference.]

A few months back I purchased a WH1081 weather station and fitted in my back garden. This was purchased from Maplin, but is also re-badged for other companies. The weather station is actually made by Fine Offset. The readings are somewhat accurate but one big problematic result was wind direction; it was all over the place. After studying why the readings were all over the place I noticed that in low wind the direction sensor would simply bat around from side to side. I figured weight to the be issue as when it gets a little gust it would turn anything from 180 to 360 degrees instead of keeping to the actual direction. Now, the weather station is mounted in my back garden which is surrounded by other houses so this is probably a contributory factor to it with wind currents due to the nature of it’s placement.

The unmodified wind direction sensor

The unmodified wind direction sensor

Note the weight in the nose

Note the weight in the nose

Whilst I can’t do anything about the placement (bar mount it on a 30ft pole, which my wife would not like), I can try and reduce the weight of the sensor to try and make it more accurate. One thought I had was to practically make a new one using balsa wood but that would take time, and some balsa, which I don’t have. So I decided to try and reduce the size and reshape it slightly.

To do this I used some heavy duty scissors, a knife and some electrical cutters.

Trimming the plastic with cutters

Trimming the plastic with cutters

All trimmed and surplus removed

All trimmed and surplus removed

Using knife to smooth it out a bit

Using knife to smooth it out a bit

Completed removing surplus plastic

Completed removing surplus plastic

Once it had been trimmed and all the surplus plastic removed it is time to replace the weight in the nose to counter balance the tail. This is very important as if the weight is not distributed evenly it will put pressure on the bearing and cause a premature failure (the same is true for mounting the sensors completely level; if they are leaning over slightly it will put extra pressure on a certain side of the bearing).

The original counter weight was about 7 grams as seen here:

Tail counter weight from nose section

Tail counter weight from nose section

To do this I used some solder. Solder is heavy due to the lead and very easy to manipulate into place requiring no tools for forming into shape etc. I made some pieces from wrapping round a screwdriver and kept adding or taking away until the sensor was balanced.

Bits of solder wrapped to make weights

Bits of solder wrapped to make weights

Once I had formed the weights I placed them into the nose. The mod is complete. Now I just need to monitor the results and see if this has made any difference to the accuracy of the sensor. If not then I guess I will have to go with my plan to practically make a new one using just the dome piece and make a brand new nose and tail from balsa.

Trimmed and balanced sensor

Trimmed and balanced sensor

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