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Soil Moisture sensor

Discussion specific to Davis weather stations
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Mapantz
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Soil Moisture sensor

Post by Mapantz »

I've picked up a brand new soil moisture sensor for £20.

I don't know which cable goes where.. the wires are green, one wire has a white stripe. There's no information anywhere to tell you which wire is supposed to go in to..

Does anybody know?
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mcrossley
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Re: Soil Moisture sensor

Post by mcrossley »

I don't think it matters which way round the wires go.
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Mapantz
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Re: Soil Moisture sensor

Post by Mapantz »

Thanks Mar, thought as much!

Got it all working. I had a special stand fabricated to mount my station in a tidy manner. I painted it all up and concreted it in, then added pipework to route all of the cables.

https://postimg.cc/3ycM350y
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https://postimg.cc/V09Hr3vW
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mcrossley
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Re: Soil Moisture sensor

Post by mcrossley »

£20 was a bit of a bargain! :o
Mapantz
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Re: Soil Moisture sensor

Post by Mapantz »

mcrossley wrote: Sun 23 Jan 2022 5:09 pm £20 was a bit of a bargain! :o
Yeah. A friend nearby had one he was going to use, but didn't realise that they come with bare wires. He didn't want to fork out for the transmitter, so he offered it to me for free. I couldn't accept it for free, so I paid £20 as a thank you. I probably wouldn't have bought one, but I couldn't resist for that price.

A weather station that I follow down in Plymouth has the full Davis set up. I noticed that they are sending soil moisture to the Met Office WoW site, but it is as a percentage.
Did you notice that offering when you added the soil temperatures?
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mcrossley
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Re: Soil Moisture sensor

Post by mcrossley »

They do accept soil moisture in percent, but there is no simple method to convert from soil moisture in cB to percent saturation, it depends on the soil type and appears to be non-linear.
I guess a linear function between something like 10 cB and say 70-100 cB would be an approximation.
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SJG1976
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Re: Soil Moisture sensor

Post by SJG1976 »

Think that's going to be my Next Purchase.

Soil Moisture Station.
But soooooo expensive and then having to add the sensors.

Leaf, soil, temp

I've currently got an EcoWitt on the go just for a cheap soil moisture sensor, that seems to read in % rather than cB

Probably wasted a bit of money going for the Ecowitt and should have just stuck to Davis...

.
GlynH
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Re: Soil Moisture sensor

Post by GlynH »

I have a related question if I may please?

I would like to use the Leaf Wetness Sensor/Soil Station as an ‘It’s Raining!’ indicator but was wondering what it would look like both in the Weatherlink app and on the Weatherlink website?

I asked Davis the question but they could not show me a screenshot or anything so I’m still in the dark about how it integrates? :?

It’s an expensive solution I know but does anybody here use one to get an early indication that it’s raining and are you able to set an alarm to be notified of the fact?

Thanks & kind regards,
-=Glyn=-
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mcrossley
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Re: Soil Moisture sensor

Post by mcrossley »

Not exactly on topic, but you can use the old Hydreon RG-11 sensors in "is raining" mode with CMX. Still pricy though!
Mapantz
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Re: Soil Moisture sensor

Post by Mapantz »

For the six months that I've been using one, I have found that at start of normal rainfall, it will register between 10 and 15 immediately. Drizzle or fine rain will jump to 2 or 3 immediately, and then increase in large increments. Developing dew starts around 0.2 and then increases in small increments. It'll take some time to work it out as you'll need to monitor it during multiple weather types.
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mcrossley
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Re: Soil Moisture sensor

Post by mcrossley »

Mapantz wrote: Tue 12 Jul 2022 2:31 pm For the six months that I've been using one, I have found that at start of normal rainfall, it will register between 10 and 15 immediately. Drizzle or fine rain will jump to 2 or 3 immediately, and then increase in large increments. Developing dew starts around 0.2 and then increases in small increments. It'll take some time to work it out as you'll need to monitor it during multiple weather types.
I see an enhancement request - to use leaf wetness sensors as "is raining" sensors ;)
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meteo19
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Re: Soil Moisture sensor

Post by meteo19 »

Hi all
Just a clarification compared to the price of this probe.
Knowledge of leaf wetness is especially useful in agriculture.
For example, for a treatment that must be done on dry foliage.
Or to know if a greenhouse should be ventilated: if the foliage of the tomatoes is too humid, there is a risk of mildew.
For the amateur meteorologist, this information does not bring much.
I have been using one for 7 years only for professional purposes and it plays its role perfectly by being an excellent decision-making tool.

Best regards
Mapantz
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Re: Soil Moisture sensor

Post by Mapantz »

mcrossley wrote: Tue 12 Jul 2022 4:02 pm I see an enhancement request - to use leaf wetness sensors as "is raining" sensors ;)
I wouldn't say no.. :)
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mcrossley
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Re: Soil Moisture sensor

Post by mcrossley »

I only just looked at the IsRaining function. It's a prime candidate for an Alarm, but it currently only works with RG-11 devices. I will lay down some ground work, then in a future build it can be configured to be triggered by other devices.
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