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Hi,
I have installed a couple of soil moisture sensors in my garden and built two different
kind of end devices mit ATMega328 and RFM95 (4 channel analog voltage input and 8 channel
analog voltage input). I use the sensors shown below (SMT50 by Truebner) since they are reasonable low cost and fully water proof for long term operation.
The system is just for monitoring soil moisture after experience with severe drought last summer in Germany. I will add valves later and work on a complete controll system.
I do have similar nodes and a weighing scale with HX711 AD converter for monitoring my beehives.
Maria
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related info
Hi @suendermarkus, this sounds similar to the Sensoterra units that I’m using for agri customers on LoRaWAN/TTN.
If you’re looking for the Sentek probe then probably best to locate your country dealer for them. I got mine sent to be by a client for the development.
Andrew
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Cool, thanks a lot @cultsdotelecomatgmai those look really interesting, too! I asked them for a quote. So I take it you had good experience with those? Are they costing much?
Hi @suendermarkus, my colleague purchased them so I don’t know the exact price but it was not expensive. We like them for a number of reasons:
- They seem to produce good data for various depths.
- The only installation tool that you need is a big hammer. This might sound like a joke but works very well with the farming community.
- The data is presented on their sophisticated dashboard but is also available via an API for integration into other systems.
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Hi, I’m working on something for the argitech, maybe you can contact me for more info.
- Measuring soil moisture and also other sensors that are special for farmers
I just started my Bonsai growing experiment with The Things Network consisting of Hardware:
- TheThings Uno
- Soil moisture sensor SMT50 by Truebner
- Bonsai seedlings from Banggood
- Bonsai soil
- Pot
Software:
- TTN client written in node.js
- Influx
- Chronograph
The idea is to improve growing by keeping the soil moisture content at an appropriate level.
I will keep you updated with my growing experiment.
https://dvs-beregnung.de/kapazitiver-bodenfeuchte-sensor-inkl-temperaturmessung-truebner-smt50-arduino
https://www.banggood.com/!de/20Pcs-Japanese-Cedar-Semillas-Bonsai-Seeds-Rare-Tree-Seeds-for-Home-Garden-p-1134763.html?rmmds=myorder
Nice project … I did some experimenting with cheaper probes and those always failed to give good readings after several weeks … And those probes look beter …
I draw the same conclusion after trying many sensors. The very low cost sensors are not durable and the professional sensors are very expensive. A sweet spot is the SMT50. There is a SMT100 as well widely used for scientific applications (hydrology, agriculture, civil engineering) but too expensive for my low cost irrigation system. A nearby nursery uses the AquaFlex by Truebner in rockwool for tomato growing, strange that they do not use real soil anymore, its more like industrial production.
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We’re tracking temperatures (looking for frost) to protect our cherry trees now in spring.
We monitor the deepest part of the orchard, because the cold air flows downwards. And if temperatures go below zero we start water irrigation and fire big candles until the sun comes up and starts to heat the orchard again. I built a website where we can watch temperatures from the phone through the night. The code of the node you can find here, it still has a problem but is working for the season now. 
If you’re more interested in what my brother is doing on the farm, the Swiss TV was there (Swiss German only) two years ago, where the frost damage was nearly 95% (!).
An image of the irrigation system
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I was working on a frost protection device for a while like @martin_schilliger, however, what seemed to be trivial at the beginning became a rather complex thing.
- dry temperature does not work well, you need to measure the wet-bulb-temperature to be sure - which requires to know at least the humidity and pressure
- sensors - the classic ones on the breakout boards do neither provide the needed accuracy nor do they support to be exposed to wind and weather outside on the field, real good ones cost lost of money
- power consumption - you need to send every couple of minutes in order to allow quick reactions or check the results of actions taken like candles/fires etc
Here is a pic of one of my prototypes
The board is a Arduino MKRWAN 1300 and the sensor is a AM2305.
Of course you will see that the batteries & board are packed into a waterproof case while the sensor is attached outside in order to capture things quickly.
Just to note: this prototype was tested for several month but was never used in “production”. Neither the battery life time (known issue on power consumption of the MKRWAN 1300) nor the accuracy of the sensor were satisfactory
BUT: was a whole lot of fun to build this thing and I learned really a lot! 
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Hi guys,
you can check my project here 
Very nice project!!! Thanks for sharing.
One question please: Did create a special “case” for the BME280 to protect it? It is not fully obvious from the pictures but seems it is mounted at the bottom of your box in a kind of pipe?
I bought the BME280 as well and want to test it but I do not want to expose it directly to wind/sun and above all rain. I saw that some people are very creative and eg printed a case (eg https://www.thingiverse.com/thing:1523429), therefore would be very interested to learn about your solution.
I made some temporary solution so the sensor is not exposed. But I’m working on finding new solution. Just send some model to 3D printing because I don’t have one yet. Sensor cover should make sun and rain protection, and should be airily to get accurate measurements. Search on Thingiverse “Stevenson” or “stevenson screen”. There are few different dessigns, but noone is ideal.
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Good information, I was looking for the same.
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